I noticed on snipers hide the new big caliber is the 6.5 Saum. They tout the barrel life that they are getting from this caliber. I noticed that they are keeping the pressures down around 58000. My question to the gun writers is won't you get good barrel life from any caliber if you keep the pressures down.

I'm not a gunwriter. But the notable thing about this cartridge is the performance they're getting (high velocities with slick bullets) coupled with the barrel life, not the barrel life by itself.

Yea but 3100ft/sec with a 140gr bullet isn't really that fast.

IIRC George won a pretty big comp shooting one with a round count over 4000.

That's competition accuracy at a very high round count and a single set back. Shooting informally and hunting, guessing 1 barrel is all a guy would ever need.

The major factor in barrel life is heat, not pressure. I doubt there's much difference between 58,000 and 65,000 psi, but the amount of powder burned directly affects the amount of heat produced. The SAUM case has a little more powder room than the .284 case, but not a vast amount.

Shoulder shape and neck length also have considerable effect, and the sharp shoulder and moderately long neck probably help.

Like I said, it's the combination of performance and barrel life.

And by the way, 6.5 SAUM is not a caliber.

It's about heat applied to the throat.

You can decrease heat at least a couple ways: by decreasing bullet throat dwell by using bullets (usually lighter) that have less bearing surface to get started;
or you can use a lubricant like moly to help them get started. Either way decreases the amount of time the throat is exposed to heat and therefore the heat absorption.

You can also decrease heat by using less powder or by using cooler burning powder. Winchester used to advertise this feature. This factor is taken into account by this http://www.accurateshooter.com/technical-articles/excel-formula-predicts-useful-barrel-life/ barrel life predictor and is a attribute listed in Quickload.

Some people say a longer neck helps barrel life too. I don't know, but I can imagine how it might shield the throat from the hottest flames.

A longer neck does increase barrel life, because erosion is greatest right in front of the case body. A longer neck protects more of the throat. A sharper shoulder also helps, because the worst "blast" of the hot gas is concentrated inside the neck, rather than in front of of it.

The military has done a lot of research on erosion, which is where I found the above info--and many other interesting items.

IIRC using a larger than 'normal' case for a bore size and slower than 'normal' powder for increased barrel life was the reasoning behind the design of the 220 Howell. I haven't seen Ken post in a long time, but a search should pull up what he's posted in the past.

I'm afraid I'd have to step on the gas with that one. I can't imagine having all that horsepower and leave it on the table to save money on new barrels, at least for a hunting gun.

Competition I can understand.

I don't think 3100 with a 140 out of that case is leaving a lot on the table.

I bet that is right. 3100 is pretty quick with that case capacity.

Hopefully Pat will see this and offer his experiences. Barrel life and recoil of this round seem amazing.

Hey John, what do you think is the optimum neck length?

Sick fu*ker.
Laffin.

+1 on that one!!!! That just TOTALLY ain't right!

I've yet to see that definition of "set back".....

Set back in a BR gun is a thread or two.

Cutting off the tenon and then some, is a re-chamber......

Does the 5-6 grains more powder that the 264WM uses to reach the same velocity of the 6.5 Saum make it that much more of a barrel burner if everything else is equal, powder ,primers, bullets etc.

I think Remington beat those guys to the punch a long time ago with the 6.5 Remington Magnum.

Yes but it has that dreaded, confusing belt

He told me it was 3000 rounds and one set back...

One theory is that if the angles of the cartridge shoulder converge inside the neck it reduces erosion. PO Ackley may have come up with this theory, could be conjecture and advertising, dunno.

Neck length the conventional rule is one caliber minimum.

3100 fps is or can be an accuracy node for the 139-143 gr. bullets. I doubt the SAUM could exceed this that much unless it had a really long barrel and run at higher pressures. Even the 6.5x300 Weatherby doesn't get a whole lot more velocity.

Either way the 6.5 SAUM or 6.5-06 AI have a lot of potential.

Still doesn't fully explain the barrel life difference between the 6.5 x.284 and the SAUM. Where does the 6.5 Rem. fall on barrel life?

The average time it takes for a bullet to leave a hunting length barrel is in the 1 millisecond range. So, assuming a barrel life of 2500 rounds, the barrel life is 2 and 1/2 seconds

I think you have that backwards... I've read many times that the faster the burn rate of the powder the less the throat erosion and therefore the greater the barrel life. Here is a pretty good read on barrel life...
http://benchrest.com/showthread.php?80875-Barrel-Life

Bob

I get that with the long 140-grain TTSX bullet out of my .284 with a 23" tube.

I wasn't wrong.
http://www.24hourcampfire.com/ubbthreads/ubbthreads.php/topics/144362/Re_220_Howell

http://www.24hourcampfire.com/ubbthreads/ubbthreads.php/topics/1835812/Re_220_Howell

Sounds kinda like what they are doing now with the 6.5 SAUM...

And a BC of .412.

Compare that to a 6.5 140 VLD's BC of .612, or the .618 of the Hybrid.....

.284? Apples and oranges with different bores sizes.

Not directed at you aalf, but I thought folks knew that.

Not to mention that I qualified the statement as pertaining to the 6.5 SAUM case.......apples, oranges, and kumquats.

Not a valid comparison. Bearing surface is shorter. Compare the 6.5 140 to the 7mm 160 or maybe the 175. A more valid comparison. 7mm velocity will be less because of the added friction of the longer bullet bearing surface.

It's not a valid comparison because:

1) it's not the case I was talking about (6.5 SAUM, otherwise known as the subject of this thread); and

2) the bore size is larger.

Tejano,

Apparently you missed my earlier post in this thread. The military has done considerable research into barrel erosion, because they burn out a LOT more barrels than any of us. Their extensive tests have proven that a steeper shoulder and longer neck do extend barrel life.

While the 6.5 SAUM's shoulder angle isn't quite as steep as the 6.5/.284's, the difference ain't much, and both converge inside the neck.

But the 6.5 SAUM's neck is almost .30" long, while the 6.5/.284's is about .27".

Nope, I got it thanks. Didn't mean to be redundant, it just still seems like an anomaly the difference that .03" of neck would make, but also it's the loading methods too I'm sure.

Check the difference at 400-500 yards. And as I've said before, with good LRF, and turrets and/or a ballistic reticle and it MAKES no difference. We now can PLACE the bullet, ...even if it drops more

The obviously obscure point is, unless you are shooting to 1k yards competitively, you are chasing your shadow. Which means I'm talking hunting scenarios.

The goal was to match the pressure of the .308 winchester and by doing this equal the barrel life. So far that seems to be the case. There is a lot of 4S shooters reporting 3000 rounds fired with no or little change in accuracy. As I understand it pressure is the key here, not heat as posted above. Heat is a factor in barrel life but not as much as you think. The link / info to the barrel life spreadsheet is not valid IMO.

The military studies on barrel life have all concluded heat is THE major factor.

Of course heat is a by-product of pressure, but in rifle cartridges the major factor in heat level is the bore-to-powder ratio.

If pressure were the major factor in barrel erosion a .300 H&H (58,000 psi SAAMI Maximum Average Pressure) barrel would last longer than a .308 (62,000 SAAMO MAP). It doesn't.

Tejano,

Neck length becomes more obvious as a factor if you look inside some rifle barrels with a bore scope. The most erosion takes place immediately in front of the mouth of the case, and drops off noticeably further down the bore, whether 1/8" or 2". A longer neck protects the part of the bore that erodes first and worst.

For what it's worth, I believe the GAP boys are claiming that their 6.5 SAUM/H1000 load runs quite cool.

Apples and oranges. The heat that a m4 or the like produces is not the same as a hunting or comp rifle. We don't shoot ours till they are smoking - not the same. Heat is part of it but not as much.

George Gardner post on SH:

Im back in town and unthawed, the Icebreaker was a great time as usual. The Xtreme Hunter is just at its debut, Im not one to just throw a product at guys without a year of testing. Yes I have over 3400 rounds on my rifle now and its still shooting sub 1/2" Bryan Yeung on Team GAP shot one to 2800 and it was still in the 1/2 " range. This is proven. Its not a real secret its about Pressure!! The 308 runs at at pressures of 53000-58000 PSI I wanted to find a case that would make 3100 with a High BC Bullet at that same low low pressure. The Saum was wat we landed at with lots of testing. With a 140 JLK I could get 3080 FPS with only 53000 PSI I shot this load for a year, guys there are many to witness, I shot this at Lonestar, Snipershide Cup, PTS, Maammoth, and Nor-Cal I shot this at last years IceBreaker, and this years as well , with alot of practice in between, all on the same original Barrel. It still shoots great. The same load is now 3020 but with 63 grains of H1000 and the 130 Berger im getting 3180 in this same warn out Rifle with that group at 1157 to prove it still has some life. Guys this is Legit its about pressure!!!! This cartridge is Game Changing and the Xtreme Hunter is the only rifle a Guy needs in N America.

I have 2200 rounds through my 6.5 SAUM, and it's still shooting really good(sub 1/2"). I have ran her hard too.....just ask my buddies who've seen me shoot it a lot in the last 9 months.

My next build is going to be a heavy comp rifle in that chambering. Within a year we will have commercial brass for it. Until then, I'll try to wear out the 1200 pieces of brass I've prepped.

rifleman700,

Ah, the statement about the .308 running at 53,000 to 58,000 psi explains a lot. Don't know what ammo's used to create those relatively low pressures (as I noted above, the SAAMI maximum average pressure for the .308 is 62,000K), but the 6.5 SAUM at 55,000 or so would definitely create less heat than if loaded to normal .308 pressures.

Pat,

Who's going to make the brass?

I have a 700 action for the 7mm SAUM, set up to screw other barrels in and out. Have been very happy with the 7mm but will probably have to fool with the 6.5 as well.

Looney!

Or is that Gun Writer?

Or both!

I have a stainless NH model 70 in 300 WSM I bought a while back just because I thought I might want try this cartridge. I've not scoped or fired the rifle, it's just standing in the back of the safe.

This site has been by far the most expensive "free" place I've ever visited!

Brad,

They're not mutually exclusive--or even financially healthy....

All of our reloading data deals with peak pressure which is directly correlated to peak temperature.

Very seldom does one encounter any data or commentary about flame duration.

I submit that there is vast difference in the amount of throat erosion caused by 6.5 SAUM with a 140 gr bullet at 58,000 psi using IMR 3031 and the same cartridge/bullet/pressure combination using H1000.

While the 260 may be loaded to the same peak pressure as the 6.5 STW, the 260 will be loaded with a much quicker powder as well as less powder. The 260 will expose the bore to peak temperature for a shorter period with each shot. (microseconds shorter, but a large chunk of time when considered as a percentage)

It is all about the pressure curve.

Tag for future reference.

John,

I thought slow burning powders like H1000 were supposed to be used near max pressure, not 53k? Is there something different about H1000 or is the risk of secondary pressure excursion, um overblown?

Jason

Idaho Shooter,

The military research does contain some info about flame duration, as I recall. They even came to the conclusion that an eroded throat tends to cause even faster erosion, because some of the hot gas circulated in the rough area, instead of flowing more directly down the bore.

4th Point,

In general any smokeless powder does burn more consistently within the general range its designed for, but a case FULL of powder will burn consistently even if the ideal pressure isn't reached.

Don't know exactly what you mean by a secondary pressure excursion.

Yes, but is the 6.5SAUM actually being run at 55k psi. In my rather rudimentary calculations, there is no way it would get those velocities at that pressure.

I did some calculating and suspect it would with enough barrel length. Or at 58,000, the upper end of the .308 pressure range quoted.

Explain why I have a box of 50 6.5 SAUM cases that have been loaded and fired 18 times, produce 3100fps with a 139gr bullet and still have snug primer pockets.....amazing how many "experts" there are out there with strong opinions on subjects they have zero experience with.

Do you have any first hand experience with the said cartridge?

Maybe you should drive up here in April and school all of us 6.5 SAUM shooters on how our rifles should run....

I would be elated to get 3000 fps from a 140 6.5 in a sa at 55K.

Pat,

What barrel length on your rifle?

24" Bartlein 1-8.7"5R

Looks I'm going to have to go barrel shopping....

I run the identical rifle as Pat, except mine is serial number 3.

I get 3140 with the 140 amax here in the 307. 61.5 grains H1000

200yard zero









I will be at Pats in April.... All the nay Sayers can show up and see the facts in person

I have over ten firings on same 50 brass... Zero issues

I actually just prepped another fifty out of boredom a few weeks back because I am gonna get a heavy rifle built in 6.5 too and start with 50 cases dedicated to it

Looks good!

I am going to try to make it this year, but have a hunt am waiting to hear on between now and April 30.

Any of that 6.5 SAUM brass that hits the ground at the shoot is automatically the property of the shoot sponser.....just so you know....grin!

Gear adrift is gear a-gift...grin.




Travis

. Roger that

Heck some of us don't have that much brass to start with, let alone part with!

So I shouldn't tell ya there is another 500 sitting by my bench then

That goes for .223AI brass too, my friend.

And yes... That group was shot with that MagnetoSpeed hanging off it

Good thing 7 Rem mags are archaic now, I don't have enough brass to give up... Grin.

Tanner

Because you are running at pressures that allow your primer pockets to stay tight. That does not mean you are below 58,000 psi.

Personally I would not get to hung up on exactly where you guys are in regards to pressure. Nothing wrong with 63,000 psi if the barrel life and accuracy holds out.

I don't for a second doubt the reported barrel life or accuracy and that is really the whole point.

A 140gr at 3100 fps is almost obsolete.



Nice shootin Scott.

Good news for this guy! I'm done with AI's. Goin' SAAMI .223 all-da-way...

But I have been buying a lot of Lapua so I'll be keeping an eye out regardless....

You know how you keep a kid from losing brass in the field? Because I don't...



Travis

Geezus will somebody go buy a strain gauge and hook it up?

The suspense on here is killing me!

Exactly.....who cares? Every time I mention this cartridge on here someone calls bullschit.....I'm getting sick of it.

John,

One of my old Hornady manuals (and some other sources I've seen) state that slow burning powders should not be reduced, but used near max charge. I think people were claiming that the rounds could "detonate" but the debate started over "detonation" and how smaller charges could somehow produce enough pressure to blow a barrel/receiver when larger charges don't. Seems that all rounds "detonate" or else we wouldn't have a functional cartridge

Secondary pressure excursion was explained elsewhere as a primer flame front that travels over the top of a partially filled case of slow burning powder. The bullet moves into the rifling but the charge isn't burning in the typical manner. By the time the charge starts burning in a normal fashion, pressures rise rapidly... so fast that the bullet now acts as a fixed obstruction and the receiver/barrel takes the stress.

I didn't know if this "secondary pressure excursion" was a real phenomenon or another gun myth.

In terms of the 6.5 SAUM, I don't doubt the results. Low pressure, but over a longer period of time using slow burning powder. Just that low pressures make me assume that there is low case fill, which made me think of the warnings on slow burning powders.

Jason

Pat,

I personally appreciate how much you have shared with all here and other sites. There is a 6.5 SAUM in my future and I look forward to shooting it enough to "disprove" everything you've written. <grin>

The case holds some 73 grains of water and a 59-62 grain load is a full power load. No worries that it will spload with H1000.

This cartridge looks ideal for hunting as well as target use.

Thanks for sharing the information.

4th point,

That's what I thought you might be referring to, the reason I asked for the explanation.

Those excursions have never been reported with powder charges less than 90% of case capacity. That's the criteria for "reduced" loads with slow powders, not pressure. The charges of H1000 being discussed in the 6.5 SAUM are well above 90%.

+1

I set out a couple of years ago to put together a dedicated antelope rifle so I had Gre'tan rifles put me together a 6.5 X 47L on a rem700. The finished rifle was a little heavy for what I wanted in a hunting rifle so I retired it to practical comps where it has excelled. Since then I have been once again researching the best possible antelope cartridge / rifle combo. This is when I found the threads that Pat and Sendero posted on SH and it did not take long to realize that there was something to the 4S. So I ordered a GAP Non Typical which santa delivered a couple of days before Christmas. I prepped my norma brass and I will soon be wringing it out. ( work has had me very busy ) I expect nothing but performance from this rifle / cartridge. I also bought a LRHS that will go on my lightweight 6.5 creedmoor.

Thanks Pat, Sendero and George!!

Excellent. Thanks for that info on case-fill John.

Jason

This cartridge and concept sound great.

From what I think I see, are you 6.5 SAUM shooters using short actions with box mags or any of you using a long action so the VLD's can be seated out?

I'm not really crazy about the extra weight of a box magazine for a hunting rifle.

GA Precision Extreme Hunter
6.5 SAUM

Templar Extreme Hunter short action
Bartlein 8.7 twist, fluted barrel @ 24�
Vias brake
Manners 100% Carbon Fiber SL stock
APA bottom metal
Jewell HVR trigger
Talley LW rings
NF 2.5-10x42 scope


Rifle as pictured, weighs right at 9 lbs.




Mag release is integrated into the trigger guard

Most everyone is running a short action with the DBM. The front plate of the mag is removed to be able to load out longer...

Little extra weight is of no concern for me to gain the incredible reliability of a center feed mag. Never had a single feeding issue ever on these type of mags.

I personally don't care for the ultra light hunting rigs. The little extra weight makes for a very solid platform that I am comfortable with and know I am capable of making the shot, weather it is prone or the seldom used by me, off hand shot.

Just my opinion, not every ones.

I'm about to order a couple of stocks, and have a question about the Manners SL.

Most guys I see using the stock also use a pad on the comb. Is the comb not high enough for a good cheek weld with appropriate optics? I'm picky about comb height and have never handled that particular stock.

No issues for me with the cartridge or the rifle. I don't know if it's lust or envy, but I want one!

Same thoughts here. If I can ever shoot out a 7mm Rem Mag without selling it, I'd love to have a 6.5 SAUM done up. That might be the cat's behind on a 700 Long Action with a blind magazine.

Tanner

I have a Manners SL and I really like it.
It is in my opinion not the best option for a lot of prone shooting.
The comb is a bit low for me which is normally easy to fix with a stock pack but the thickness of the stocks cheek piece combined with the stock pack then pushes the shooting eye a bit to much off center.

That being said I can live with because I really like the stock.

I think the Manner EH2 or EH3 would be better options if you are doing a lot of prone shooting with a less than 9"height forend support.
Just my $0.02.

I found a cheap way to try a couple DBM's and I can't believe how flawlessly they feed. There's something about them I don't like, but I like them anyway.


Travis

That's about the same case capacity as my 6.5-06 AI if I'm not mistaken. A really accurate load for me is 60.5 grains H-1000 behind a 140 Berger, which gets 3050 with a 24" barrel. Given the same case volume and the lower velocities I'm running at, I'd assume I'm running at lower pressures than the 6.5 SAUM pressures, or at least no higher. But I don't get nearly the case life that the SAUM guys are getting, my primer pockets are loose at around 4-5 firings, with 2 different kinds of brass.

Maybe part of the difference is due to the stoutness of the SAUM case??

Very Nice. Does that 9 lbs include the sling and bipod?

One source puts the 6.5-06AI at about 71.5 grains water, not sure about the .270/.280 versions probably almost the same as the SAUM. That and the 6.5SAUM usually have more barrel 26-30" so they are running lower pressures, not a whole lot lower though.

Brass is thicker for the SAUM but at high pressures that doesn't always add up to longer brass life. Brass has the same strength and fatigue factor regardless of how thick it is.

Hope some one doe's an article on this one with pressure info.
Even if all the hype doesn't pan out (I think most of it will) it is still a worthwhile cartridge.

An interesting experiment would be if someone could get hold of .284 basic brass and come up with a 6.5x.284 with .300" or longer neck for comparison. Some of the wildcat versions do this by setting the shoulder back and they claim slightly longer barrel life.

Gracias, Tejano.

I am in the process of gathering parts for a build. I was going to do a 6.5 Creedmoor but now I am very tempted to do 6.5 SAUM. I guess the only thing holding me back is the lack of ready to roll brass. I wish I knew when the brass will be offered and who's brass it will be.

Does anyone see a problem with running a Wyatt's mag box in a 700 BDL configuration -either for length or for feeding- as that is my plan.

Thx,

Bob

I think most are necking down Norma/Nosler 300 SAUM Brass.

I would imagine a Defiance XM action with the longer XM bottom metal would work great, and be a little lighter, I heard GAP had built a few on this platform and had good luck!

Remington 300 SAUM brass works well.

D,

I picked up an EH-3 recently for my 6 Creedmoor build. I'll bring it down next time. Along with a few other rifles to shoot!

Since this appears to have been directed at my post, I guess I'll give an answer.

Your primer pockets staying tight do not indicate what pressures you are running at in any chambering, and you already know that. They indicate far more about the build-quality of your rifle and your ability to reload nearly-perfect ammo.

I do not have any personal experience with said cartridge, though it looks intriguing; hence, why I have followed it here and on AR since its inception.

I will not make the April Icebreaker, and if I did, I would in no way "school" you or anyone else on how to run your great rifles. You-all would run circles around me.

In the end, I am simply curious what exact pressures are being run in the 6.5SAUM, since by any typical comparisons to pressure-tested data (say in the 260 or the 7SAUM), the velocities sure look like they would generate in excess of 60k psi, and more likely 65k. I see absolutely no problem with that, but also think that the cartridge is being spoken of in "low pressure" terms that don't actually apply. I enjoy learning about the physics of rifle chamberings, and look forward to reliable pressure-tested data on the 6.5SAUM.

I know one of the Hide members has tested the pressures. I will contact him and see what he used and what his results were...

More to come !

Who gives a shat about the exact pressure. If brass life is good and velocity is good rock on IMO.

Apparently all these non-believers and nay-sayers !

I don't care if they drink the Kool-aid !! More for me

Then why do "they" bother to make the claim. They obvious give a shat, and you should too.

Nobody "really" knows, and until there is hard data I am skeptical at best.

I would submit that brass life wouldn't be good if pressures where high... If Pat says its so that's good enough for me.

If I thought there would be ANY danger, my 13 year old wouldn't have used it for his deer and antelope last fall.

I tested those loads when it was 110*F last summer with easy bolt lift, no primer flattening, or cratering. If there was excessive pressure, I would have seen it then.

Some folks sit in the stands.....some play the game.

Pat, I'm very glad your 13 year old is safe, no doubt.

But until you play the game with hard data you're just yelling from the stands with guesses.

Awesome--I'd love to see that data.

Nice buck!!

If SAUM brass is anywhere near as 'strong' as Winchester WSM brass it can last +15 'full power' firings without any loose pockets or other issues. I had/have a bunch of 300 WSM brass and it literally lasts forever.


I have heard several people mention that WSM brass is heavy duty stuff, not sure if the same holds true for SAUM brass. If so, pressure aside, that might explain the longevity.



It will be interesting to see the actual pressure data.

Obvoiusly Pat has something up his sleeve re: brass... hopefully it's Lapua. Regardless, factory brass could tempt me to the 6.5 SAUM... I've always liked the SAUM case better than the WSM.

I've been shooting and handloading the 7mm SAUM since it appeared, and the Remington brass I have (all early production) is VERY good, both in toughness and uniformity. Obviously the pressures Pat's running aren't causing the slightest problem.

My only skepticism at this point is the claim of extended barrel life due to lower pressures. After running some calculations, the pressures with a 140 at 3100 from a 24" barrel would have to be over 60,000 psi, probably closer to 65,000.

But that doesn't bother me either. If the barrel life is there, it's there, whether or not it's due to lower pressures, case shape, or whatever. SOMETHING is causing it to be an outstanding combination of caliber and case.

Not exactly sitting in the stands here, Pat.

Here's a 6.5 Rem Mag. Bartlein 24" 1/8 8 lbs, based on a long action with a long throat.
I'm shooting 140 VLDs with 60.0 of H1000 at 3,020. 56.0 7828 SCC at 3,051. My hunting load is RS Magnum 60.0 fetches 3,150.

Wither I am getting the same barrel life is to be seen. I'm not to worried about it.

That about sums it up. I wish we could figure out exactly what allows for the great performance with barrel life, then apply the same science to other new chamberings.

MD, you would think the 6.5-06 Ackley would get the same or better barrel life do to it even having a longer neck and sharper shoulder than the SAUM.

But based on testimony apparently it does not.

If I knew for sure factory brass, I would build now with the parts I have for my 6.5 Creedmoor build.

Pat spill the beans so I can change direction on my build!

Even without factory brass, you can neck down one of the other SAUM parents and be good to go. Nosler just had a bunch on closeout/overruns.

SU35,

Don't know. Do know a bunch of people who've seen less rapid throat erosion with the 6.5-06 (either standard or AI) than the 6.5/.284, which has approximately the same case capacity but a much shorter neck.

DD I realize that but factory brass is a huge plus to me.

Well this might just seal the deal for me.

Im having one built right now , it isnt a "new" catridge they were being built before these guys brought them to attention via the intertube. But it is an awesome round no matter how you look at it. My gunsmith believes it has a lot to do with powder choice. He claims they go around 2500k to 3k before needing to be set back to retain ridiculous accuracy , hunting accuracy past 3k. (this is according to him , not me). If anyone doubts what these guys are saying please dont build one to findout , you will just be wasting precious components

I give up.....you guys know way more about the cartridge than I do.

Others were building them, but GAP seems to have perfected the design with some tweaks here and there that make it all come together in a much better package. Others who built them early on seemed to report little nagging problems, but George figured out what makes it run best (throating, leade, chamber, dies, etc).

yup and I think they are awesome

yup and I think they are awesome

Its the internet , everyone knows more than everyone , and facts mean something other than the truth , its magic , better off just looking at T&A , at least youll feel good when you are done looking

Hey not so fast!


If Pat says the cartridge is good, that's good enough for me.No need to inquire further.

Yeah, but I don't think that George dude knows how to build rifles....

Chuckle....

If there is anyone here that knows rifles and how to hit things at long range under field conditions better than Pat, I wish someone would be kind enough to point them out to me.

Add me to the list of folks waiting for commercial brass to be available!

I never doubted George or Pat. I know they are both honest good to go guys. They also most likely forgot more then I know. So anytime they post I read and take notes.

So here is my parts list either on hand or already ordered:

Stiller Predator Action .308 bolt face
Bartlein SS 1-8t 6.5mm Rem Varmint contour
JEC Muzzle Brake
Seekins DBM Bottom Metal
Seekins Low Mounts 6/4
Bushnell LRHS 3-12X44 scope
McMillan HTG Stock GAP Camo

I don't understand why some people cannot grasp the pressure concept here. Yes 308 winchester is saami rated for 62K but who loads to that pressure? Hodgdon shows starting loads in the 42K range and max loads in the 58-59K range. There are a couple at 61K but these are fast powders being used and not optimum. I would guess also that factory ammo is loaded in this lower range also.

As far as brass - remington brass in my opinion is only average in quality. The Norma brass that I am using for my saum is stouter and because of this will hold less powder, but more than that it tells me that by comparing the two different makes of brass that the remington brass is just their ordinary run of the mill brass, and it was not designed as some super pressure holding vessel as is being suggested above. And then this all comes full circle back to the point that if there is nothing special with the brass and primer pockets are tight with 15 reloads then the pressures have to be lower. No remington brass has a long life with high pressure loads. I learned this in my 37 years of handloading.

Its all stupid simple and once somebody does post some pressure data on the saum I am sure someone will discredit them or their testing criteria or some other BS!!

I have one, do you???

All this "hype" got me back out to the range.......A bit frosty, but dead calm this morning.



I put 32 rounds on steel, then shot the last 18 at 200. Now I'll load this brass for the 19th time. Round count: 2288.

Black bears beware.........

Is that a 26" barrel?

24". Vias brake adds about an inch. Recoil feels about like a .243 of the same weight without a brake.

Excellent. I was hoping that 24" would be good to go. I will have a JEC brake on mine. I am looking forward to getting mine built.

That thing is a Laser.

I'm hoping my comp rifle shoots as good.....130 JLK's at 3300 should clip a few extra targets in the wind. That barrel will be 27".

rifleman700,

As noted in my earlier post, I absolutely trust everything Pat is saying, including the velocities he's getting from his 24" barrel, and the long brass life and barrel life.

The only thing I questioned was the claim from others that this is due to lower pressures, because of the 3100 fps with 140-grain bullets from 24" barrel. And so far nobody has provided any proof of the pressures, other than long brass life.

I've had very different experiences with my batch of 7mm SAUM than you say I should. I'm still using some of the same brass obtained when my 7mm SAUM was new, 11 years ago, and haven't had any problems, even when some of the loads tried exceeded listed handloads that are rated at 63,000+ psi.

I just looked up some pressure-tested data from Ramshot/Accurate for the .264 Winchester Magnum, using Accurate Magpro and Ramshot Magnum powders and various 140-grain bullets. Not a single load exceeds 3100 fps from a 24" barrel, and all the loads listed are 63,000+ psi.

Now, over the decades there have been many claims made about special cases that got more velocity than their powder capacity would indicate. These have been made about both wildcats and commercial cartridges, but every time the cartridges have been tested electronically, by either strain gauge or piezo, the pressures the magic loads have produced have all been a lot higher than the inventors claimed--even when no other indication of excessive pressure appeared. This is because most brass doesn't start to show any signs until around 70,000 psi, and some will go even higher.

I just measured the water capacity of fired 7mm SAUM and .264 Winchester cases filled to the mouth. The SAUM held 74.5 grains and the .264 87.4 grains. I'd like to know how the 6.5 SAUM gets the same sort of velocities as the .264 at even less pressure, when the SAUM holds only 85% as much powder.

If it does, it would be the first time in ballistic history something like that occurred. Which is why I am VERY interested in actual pressure data from the 6.5 SAUM.

Pat, do most comps you compete in not worry too much about the impact velocities on steel? I remember seeing some regs that had like a 3100fps muzzle velocity ceiling? I know I wouldn't want to be a piece of AR-500 in front of that...grin

130 JLKs at 3300 is just ridiculous. Almost unfair!

Tanner

MontanaCreekHunter... You ordered a second bolt with a mag bolt face too I hope...

Our 200 yard targets look very similar

Think how'd they look if we knew something! Grin

I'd be grinning if I could get all my sporters to shoot 9-10 shot groups that well at 1/2 the distance.

Brass - If you say that you are getting good life out of your 7saum brass - fine I will not argue that point. I am just relating my experience with rem brass.

264win vs. 6.5saum - Apples and oranges. Two different cases and can't be compared. Example, why does my 7RUM not out run my 7STW until I get to 180 gr bullets? I am using more powder?? And my stw has a 24" bbl and the rum has a 26" bbl. For whatever reason the stw is more efficient, plain and simple.

One thing to remember here is that the 6.5saum velocities are not max loads, but moderate. They will run a lot faster. I might have to dig up my Oehler 43 and see what pressures it is running just to put this to rest.

I would have to say that the entire reason is that the comparison between the two is bogus simply because the two powders being compared aren't that close in burn rate and may not act the same in the different cases. H-1000 is much slower than Magpro and Magnum. When a faster powder is used in a large case, pressure is found early.

This is easy to see during load development with different powders in the same cartridge.

I believe velocity isn't necessarily the best indication of pressure.

For example, in the .264 Winchester Magnum, just about every powder you'll find with data for the cartridge acts like pistol powder. Even some of the slowest burning powders on the chart. Velocities are anemic and pressure signs show quickly.

With extremely slow burning powders in the .264, pressure indications don't appear until well after its velocity potential is attained. I'm talking about 3250 + fps

It looks like H-1000 is just right for the 6.5 SAUM and its case capacity

Playing devils advocate. Lets say the pressure of Pats loads are 67,000 PSI. Hes getting good brass life and the gun will handle alot more than that before failure so why worry?
I have seen factory 300 WSM loads and Weatherby factory ammo show very obvious signs of pressure, so why get worked up over 2000 PSI or even 5000 PSI over 65k where traditional pressure signs show up by.
Keep in mind I am asking a question not advocating running pressures over 65k.

rifleman700,

As I mentioned in my first post, there's no ballistic evidence that any cartridge is more "efficient" at burning powder than another. All the pressure tests ever run have shown exactly the same thing: Powder capacity is the lone determinant of what velocity can be reached.

If you want examples I can provide them, but you seem to have already made up your mind.

Rick,

No, H1000 isn't "much slower" than Magpro or Magnum. You can easily check that out on any burning rate chart, or loading data where all three can be found.

Burn rate also varies somewhat due to the specific application and manufacturing lot. In my first .264 (a Westerner with 26" barrel) Magnum was slower than Magpro and Retumbo--and Retumbo is slower than H1000. I know this because it took more Magnum to reach 3200 fps with a 140 than it took Magpro or Retumbo.

And yes, velocity is a very good indication of pressure under specific circumstances. In fact without electronic pressure equipment it's the most reliable factor for handloaders--and this has been proven many times over, just like the myth that case shape can increase "efficiency" and produce more velocity with less pressure.

Again, I can provide proof of that, performed in actual professional pressure labs, not some wildcatter's mind.

You didn't answer my question.

Right from the hodgdon website, no data of mine.

7MM STW 175 GR bullet 88 grs US 869 3020 fps 62,800 psi = 34.31 fps per gr of powder

7MM RUM 175 GR bullet 102 grs US 869 3077 fps 63,000 psi = 30.16 fps per gr of powder

These were the first combos loaded so thats what I went with.

The STW case is more efficient with this powder bullet combo. Its greater with lighter gr bullets in my testing.

Now what I have found while using my Oehler 43 that I agree with you on is that velocity does equal pressure. I may not get the stated velocity - rarely with the charge that Hodgdon shows with the lot of powder they are using but if I load to their velocity I get their pressure.

Pressure is going to vary from rifle to rifle. Just because you reach 3077fps with US869 doesn't mean you're at 63,000 PSI in you rifle.

Exactly. Loading manuals give you an idea what the bulley/powder companies got on their guns/test rifles on a certain day with a certain lot of powder/primers/bullets.
Each gun is an animal unto itself IME.

Yes there are exceptions as every barrel is different but it was often enough that I only use my Oehler 35 now and not the 43 and I watch for pressure signs in load development. I very rarely chase velocity anymore anyway and look for accuracy / velocity nodes.

I have even seen bbls like pac-nor that for whatever reason have tighter tolerances and do not like higher velocity loads and show pressure signs early. So yes that is a good point and I admit the last statement was a little general in nature.

Further more I run mostly cut rifled canted lands bbls. These I have found to be more consistent - to ME.

You're correct.

They're all very close to one another

I guess what I'm saying is consider loading the .264 win with IMR 4350 and Retumbo both with a 140 grain bullet.

When 70,000 psi is reached in each load, the IMR 4350 load's velocity will be nowhere close to Retumbo's

Correct?

Lost in the gack, is brass life (pockets) is increased with a good chamber with a reamer that matches the brass in the web area, without getting dimensions too tight. That'll open up another can of worms.

Some prefer to shoot their brass a time or two to work harden it, and claim better primer pocket life as well.

There's more to this than meets the eye.....

Rick,

Yep, that's correct.

Now, the .264 will get some more velocity with even slower-burning powders. I've got a bunch of US869 and H50BMG on hand, partly because I'm going to be handloading the .26 Nosler in the next couple of months, but I'm also going to try them in the .264.

But one basic formula for internal ballistics is that when using the optimum powders for any cartridge, any increase or decrease in powder capacity for that caliber is going to result in 1/4 that amount in potential velocity--AT THE SAME PRESSURE.

Even if we can get another 100 fps out of the .264 in a 24" barrel at 63K psi with slower powders, the 6.5 SAUM is going to be around 4% behind (15% less case capacity = 3.75% less velocity). So if the .264 is capable of 3200 with a 140 at 63K, the 6.5 SAUM is capable of about 3070 with a 140 at 63,000. (Remember, this is using the optimum powders, not the same powders).

Another basic rule of interior ballistics is that with single-based powders like H1000, pressure increases at twice the rate of velocity. Another rule is that velocity with single-based powders increases at the same rate as the powder charge.

If we apply those formulas to the 6.5 SAUM, a 140 at 3100 will be producing around 64K psi. Of course, this will vary some with the bullet, but I am willing to bet that the loads being discussed produce over 60K psi, probably around 65K and maybe even more.

One classic example of how poorly tight primer pockets indicate actual pressure is the 7mm STW. When Layne Simpson developed the round, he used all the standard pressure "indicators", ahd reported 3600+ fps with 140-grain bullets in 26" barrels with no problems. A bunch of other people built rifles and reported the same basic velocity level.

When Remington decided to make the 7mm STW a factory round, they pressure-tested Layne's loads, along with some others. ALL were at least in the 70,000 psi range, and some were around 75,000. That's why no factory 7mm STW load is listed at more tan 3400 fps.

This has little to do with whether or not such pressures are "safe." Obviously Layne and others shot such loads a lot (with the dreaded Remington brass) and never had a problem. Similarly, a lot of people who're loading and shooting the 6.5mm SAUM haven't had any problems.

But tight primer pockets prove exactly one thing: The primer pockets are still tight. They're not even an approximate indication of actual pressure.

This is exactly why I believe velocity is not the best indicator of pressure.

You have stated that slower burning powders are able to produce more velocity at the same pressure as faster burning powders, and that's what I'm getting at.

On the Hodgdon site, data for the .264 win with a 140 partition shows this:

Retumbo at 2900 fps and pressure of 57k+

IMR 4350 at 2900 fps and pressure of 61k+


Also in my Creedmoor with an old lot of faster burning H4350, I hit traditional pressure signs of sticky bolt and ejector marks at 42.5 grains and velocity below 2800

With a new, slower burning lot of H4350, pressure signs were not noticed until 45.3 grains with a velocity of well over 2900 fps

If pressure is directly tied to velocity and can be predicted by velocity, how can the above happen?

Rick,

Obviously different powders are going to result in different velocities at the same pressure.

But the formula for predicting how much velocity a case with a certain capacity is capable of uses OPTIMUM powders, meaning the powders that get the maximum velocity out of any given case--not the same powder in different cases.

We have enough powders today that optimum powders for any case size, bullet and velocity are easy to find. If some case is producing more velocity than the formula predicts, pressures are higher.

Velocity is also a very good indication of pressure in different barrels chambered for the same cartridge. For instance, if we have a .270 Winchester with a 22" barrel that gets 3200 fps with a typical cup-and-core 130-grain bullet and 60 grains of H4381, we can be very sure that the pressure is higher than the "normal" 62-64K psi. Similarly, if velocity is only 2850 with the same load, we can be sure the pressure is lower.

All of this has been proven on modern pressure equipment. The top techie in a major pressure lab says that pressure will vary about 800-1000 psi with each 1/10,000ths of an inch variation in bullet OR bore diameter. He's proven this by years of experimentation.

So yes, velocity is an indication of pressure, but we have to know how to apply it.

Thank you for your time here; I'm sorry to "hijack". LOL

But...




"Optimum" powders in each case change as technology changes.

IE, RL-33 in the .264 Win Mag.

If you don't test it in the 26 Nosler you'll be missin' the Boat!

Rick,

Yes, they do--and they change in all cartridges. But the formula still provides a very good idea of the differences in potential between cartridges.

I've been trying to get some RL-33 for over a year now! I'd like to try it in several rounds--but Nosler's testing doesn't have it among the front-runners in the 26.

I have plenty to send to you.

Thanks very much for the offer! Let me try a contact at ATK first and see what happens.

It appears to me that the closest pressure-tested comparison we have to the 6.5SAUM is the commercial 7SAUM. Looking at that chambering with a 140 grain bullet, all the best loads run 3100-3150 at 62-64k psi. The 6.5 cannot ran at any less pressure than that to accomplish the same thing, and due to being a smaller bore diameter would have to have the pressure a bit higher. I think that it will test out at right around 65k psi in the end.

John,

Lots of good thoughts here.

Thanks for taking the time.

The last time I was in Cliff's Reloading in Boise they had a lot of RL-33 in stock. (there is a reason they have a good supply on hand. I paid $33 for a can of 4756 which I felt I absolutely could not live without.) I really need to grab a can of RL-33 and do some more experimentation with my 27 inch Pac-Nor 264.

DakotaDeer,

There's even an approximate formula for the same case but different calibers: Divide the cross-sectional area of one cartridge's bullet by the area of the other cartridge's bullet, then divide the difference by 4.

Here it would be .0633 (7mm) divided by .0547 (6.5mm):

.0633 divided by .0547 = 1.157
.157 divided by 4 = .0392

Then subtract .0392 from 1, and multiply the result times the velocity of the larger-bored cartridge:

1-.0392 = .9608
.9608 x 3175 (velocity of 140 in 7mm SAUM) = 3050 fps

This would be the approximate potential velocity of a 140 in the 6.5mm SAUM at the same pressure as a 140 from a 7mm SAUM, at around 62,000-63,000 psi.

Just checked the Hodgdon site, and the top velocity with a 140 in the SAUM is 3217 (with H100V). That would change the calculated maximum velocity with a 140 in the 6.5mm to 3088 fps--again, at right around 62-63K psi.

Just to keep this little diversion going a bit longer...
One thing that's easy to forget as a handloader (but I'm sure most know) is that the pressures quoted in a reloading manual and elsewhere correspond to the peak pressure experienced while the bullets moved down the barrel. The pressure however is not constant. Speed is maximized by choosing the powder that will give the highest average pressure without exceeding your maximum pressure criteria. With the big magnums, a faster burning powder may hit the same peak pressure as a slower burning powder but its average pressure as defined by the pressure curve will be lower for a given max value.

All gack. Just build the damn thing and choot the hell out of it.

That's what I'm talking about!^^^^^

I mentioned something similar a couple months back based on Hodgdon data and the 264W vs 6.5 SAUM. Was told the bullets being used in the 6.5 SAUM were lower friction due to lower bearing surface compared to the hunting bullets I was referring to. This was given as the explanation to the low pressure and high velocity. I could see 1k psi or so, but didn't think it would make that much diff (i.e. 62-63k vs 58k for 6.5SAUM).

At that time I went back and reviewed a bunch of posts at the other site and from what I gathered, it seemed like GAP was using low pressure (58k) and getting great barrel life. Then pressure went up and I don't think GAP was claiming great life anymore (although that might have still been true). BUT, it seems that the casual observers were still mentioning the great life even though George set-back 1x in 3000 rounds. Seems to me that once the idea of low pressure got into people's minds it stuck. And barrel life. But, I don't doubt Pat's claim on barrel life either.

The pressures are more interesting to me and would be easy to measure. I'd like to see the max pressure, but also the area under the curve compared to some other carts like the 7SAUM and 264W.

Jason

Karnis and Pat are on the right track......

John, you obviously have a handle on this. If you have a quick way to estimate, and could hazard a guess on the pressure generated by a 6.5-06 AI pushing a 140 grain VLD out of a 24' barrel at 3050 with 60 grains H-1000, I'd be much obliged.

If not, no worries.

Karnis and Pat on the right track? Who'd have tthink it.

4th_Point,

That's interesting about the bullets, because of the four bullets listed in the Ramshot/Accurate data, three are the 140 Berger VLD, the 140 Hornady A-Max and the 142 Sierra MatchKing, hardly a selection of typical "hunting" bullets.

The fourth bullet is the 140 Nosler Partition, a bullet noted for producing more pressure 9and velocity) than others with the same powder charges. Interestingly, the Sierra MK requires the least powder to reach 63K psi, whether using Magpro or Magnum, indicating it creates even more pressure than the Partition. The A-Max requires the most powder to get to 63K, with the Berger VLD right behind.

smokepole,

Hodgdon's 6.5-06 data lists 55.0 grains of H1000 as maximum with the 142 SMK, for a little over 63K psi and 2800 fps from a 24" barrel. In my own 6.5-06 I used 56.0 grains with the 140 VLD for 2950 from a 26" barrel. Don't the pressure but guess it would be about like the Hodgdon load, given that the 142 SMK produces a little more pressure than the VLD.

The 6.5-06 AI has just about the same case capacity as the 6.5 SAUM. Given that, and the data from Hodgdon I'd guess you're getting similar pressures, somewhere in the 63K range. But I emphasize GUESS.

I never could figure out why the 7mm SAUM wasn't more popular, because it's basically a short .280 Ackley, and allows enough room in a .28" magazine box for really long bullets. It's also very accurate and kills stuff!

Gack is Good. Keep fanning the flames.

At one time I think the 6.5 bore had more variation in bullet bearing surface than any other caliber. With all the two diameter "bore rider" bullets that came out with the .264 WM and now three diameter if you count the driving band on some target bullets.

Sometimes these were changed by the manufacturer with no notice.

I think this is why results vary so much even with the same weight bullet. The difference between a sticky hunting bullet and a soft two diameter target bullet could easily be 3,000 PSI or more.

Thanks John.

Mule Deer,

I find this formula very interesting. I would have guessed that with the only difference being the diameter that the 7mm would have had more pressure and less velocity due to the increased surface area / friction / force?

This is a good thread and has certainly cut into my work performance the last couple days...:)

What's the fun in that--gack makes the world go 'round!

Some day someone will give us relatively affordable pressure measuring devices, like they did affordable chronographs. I suspect this will eliminate a lot of speculation.

I also suspect it will burst some bubbles for all of us.....the way chronographs did when we discovered our pets were not going as fast as we originally thought.

But I bet it won't stop the conversations though,because we will then discuss why pressures with the same components are different from one rifle to another....it will never end.

Yup... I keep getting an image of a dead horse and a bunch of guys with sticks in their hands....

rifleman700,

I should have been more clear. The formula (like the other on case volume) involves optimum powders for the case in question, those resulting in the highest velocity. It's not for the same powder, or powder charge, with the same bullet weight.

The big factor in different bore sizes is expansion ratio, since the volume of the bore adds more room for gas to expand. In a larger bore (say 7mm versus 6.5mm) this slows the pressure rise, allowing more "area under the curve" for more velocity with the same bullet weight.

Both of the formulas were worked up by me a number of years ago, empirically from loading data. The validity of the physics was confirmed afterwards by the late Don Miller, the guy who developed the rifling-twist formula included in Bryan Litz's book APPLIED BALLISTICS FOR LONG-RANGE SHOOTING. Don published a couple of articles on my formulas, I believe one in PRECISON SHOOTING and another in VARMINT HUNTER.

I started crunching numbers because there was so much speculation about how powder capacity changes potential velocity. A lot of folks assumed that "improving" a case resulted in the same percentage of extra velocity, and it doesn't--at least not at the same pressure.

The bore-diameter formula resulted from the same sort of curiosity. Obviously the .270 Winchester is capable of higher velocities with the same bullet weights than the .25-06, but I wanted a formula that would predict potential in various cases.

Like all formulas, there's some variation due to different bullets, but both provide a very close approximation of a case's potential, because they were developed from hard data from a bunch of different sources.

Not trying to nitpick here, but for the purpose of this discussion, heat and pressure go hand in hand.

The first law of thermodynamics states that heat and work are mutually convertible. As it pertains to gas in a pressure vessel, "work" is defined as change in pressure times change in volume. Therefore, heat IS pressure and pressure IS heat. During combustion, you cannot have low heat and high gas pressure or vice-versa

Therefore, pressure is a major factor in barrel life. Maybe not the only factor, but a comparison of pressure is a good indicator of relative barrel life.

Let's see, break out the physics book and read up on the first law of thermodynamics, or just "choot the chit out of it.?"

Tough choice.

But what that means is you'll ultimately "choot less chit out of it" if it's generating higher pressure (and therefore heat).

EDIT: or is it "more chit?"

No, I need to choot the chit out of my 6.5-06 AI first, and see if I can keep up with the SAUM guys as far as round count.

More chit/less chit, I could give a chit!!

20 pounds of H1000 used so far in my 6.5 SAUM and counting. I've got three more eight pounders on the shelf.....I'd like to know how many guys on here have actually wore out a rifle barrel...

I have. But it took me about 15 years.



Travis

What kind of pressures were you running?.....grin!

Lol!!

I have worn out two, they were a 7mmSTW and a 257 Weatherby. My fault, most of the time it is hot when we shoot and don't let the bbl cool down enough.Thats in 35yrs of shooting.

Higher than they were supposed to be I can tell you that.

That was my only rifle for a long time and work didn't allow much shooting. Glad that stage of my life is over. grin...



Travis

Couple.....

I've killed a couple, and my 243 is hanging on for dear life. If I ever kill the barrel in my Tikka I am going to cry and head to counseling.

RifleDude,

I acknowledged the duality of heat and pressure in an earlier post.

However, wear in a rifle barrel is a little more involved. There's also the duration of the heat, and the heat is mostly caused by burning powder, though some comes from the friction of the bullet heading down the bore and the primer.

I used the examples of the .308 Winchester and .300 H&H Magnum. The SAAMI maximum average pressure for the .300 H&H is 58,000 psi, 4000 less than the SAAMI MAP for the .308. Yet the .300 H&H will burn out a barrel noticeably faster, because the case uses 50% more powder, and the duration of the powder burn is slightly longer with each shot.

Of course, the .300 H&H does have a very long, sloping shoulder, which has an effect on the throat as well. But we could use the .300 Winchester Magnum as an example. It's MAP is 64,000 psi, only 2000 psi more than the .308, and it will also fry a barrel considerably faster than a .308.

One every other year.

So far maybe 5... but I have many more rifles than in those days...

If I had to bet, I'd wager that was a rhetorical question.........

+1

Yes Indeed!!




I've never messed with the 6.5 SAUM but I've enjoyed this thread immensely.


The above formula (equation) is a prime example. Very interesting and beneficial.

THANKS from me too!!

I will continue to keeping shooting it, until the barrel pukes.

One of the things I've found very interesting, is I haven't "chased lands" with this load, or any other load for that matter. I've used the same BTO for almost everything I've tried. Testament to an excellent and precise job of cutting the chamber, very good barrel, and good reamer.

I have 250 140gr JLK's arriving soon that I'm excited to try next. Swampworks claims a .700 G1....we'll see.

Pat, just curious, has the distance to the lands increased? Not that it matters when it's shooting like that.

I haven't checked it, but I will.

FWIW, I haven't cleaned the barrel in 233 shots.

I wouldn't clean it either. Might get it bronzed though, LOL.

Well, I guess if you can be satisfied with that large a group.... (Personally, I'd be ecstatic.)

When the barrel was new it was 2.215", base to lands. The throat has grown .0040" to 2.255". I'm jumping those 139's .0070".

Thanks Pat!

Pat, where do you get your targets?

Thanks

http://precisionplustargets.com/index.htm

I've used them for years....for my eyes, blue really works.

Thanks Pat

Lookin' good, Pat! Glad to see that rifle is still hammering!

Pat
Great shooting like always. Just curious since you measured the lands are you gonna change your 139 load to chase the lands? I see no need but just curious.

Tag for good info

That's it. I'm buying one...

Impressive.

Toldyaso... grin

.

John,

My two favorite cartridges for medium to big game ever since you starting touting the 7SAUM have been the 7SAUM and 300SAUM. I think Remington did such a poor job of marketing the cartridges in comparison to the WSM's and other recent "magnum" offerings and the fact that they quit chambering most of their rifles for them before the public had a chance to really get used to them led to that lack of popularity.

My 300SAUM and 7SAUM rifles are scary accurate and light and handy as a 308 carbine.

By the way.... I use Varget exclusively in both of mine and the performance and velocity is so outstanding that I simply have never looked further.

Long live the SAUM cartridges and I'm certainly glad I stocked up on brass when it was readily available and cheap...

$bob$

I read both of these threads carefully and couldn't find any support for what you are saying. Would you please quote the exact text you're talking about?

My article I referenced was actually about burn rate vs barrel erosion and seemed quite straight forward and what I've been hearing from the benchrest guys (read anal geeks) for quite some time.

$bob$

THIS, +1. 6mmbr.com concurs in their write-up on the 7 SAUM; most efficient case design in a short mag. I just had one cobbled together on a 700 long action.

Re 6mmbr...which in light of what Charlie Sisk (IIRC) showed with the 300H&H/WSM, would be little more than a caliber comparison within a given case "series", no?

I don't think the serious long range crowd buys enough rifles to help a new cartridge become a commercial success. (Though the 6.5x284 might disprove my point). And a lot of their rifles wear custom barrels anyway. Some of the case design features such as discussed here are of little interest to hunters who buy lots of rifles. As noted before, Remington backed off on chambering their own stuff for SAUM just as the marketplace was taking a second look. Just seemed like a commercial drag race between SAUM and WSM ...and I suppose RCM. Throw them all against the wall at the same time and see what sticks. The family that gets the most buzz early probably wins out as buyers tilt toward the one that they think will make it long term. The 6.5 SAUM would have been an interesting cartridge to launch commercially against the .270 wsm. Perhaps the world will never know!

PV=nrT There is a direct relationship between pressure and temperature.

Anyone using Retumbo in the 6.5 SAUM? It's close to H1000 in burn rate.

Retumbo works great in the 6.5 saum. Just a bit slower.

RS

BG-

Slower as in velocity or burn rate?

Marlin XL7 action with 26" Mcgowen savage magnum contour barrel with Harrel's brake. Super fun rifle to shoot,fast,accurate, and the cartridge is impressive. No pressure issues and seems to be real easy on brass so far.

Load Data:

Newest spec. GAP 6.5SAUM 4S reamer.
7mm Rem brass necked down, .291" bushing, and turned to .015" per Pat's instructions.
140 Berger Hybrid
H1000 Powder
CCI-250 Primer
COL @ 2.902" -.018" OTL
Shoots .3's to .5's @ 100 yards. Worst group while testing 1 1/4"

Speed average for 8 shots is 3142 fps with 12ES.

Prior 5 shots:

Doing some light reading on this fine winters eve and found this.

With the arrival of plenty of factory brass, I wonder how many here now have a 6.5 GAP (SAUM)?

Mule Deer, will we see an article on it this year?

You never know. I have an action that would work.

MD : Like a lot of these SA cartridges , they seem to be better suited to the Intermediate Length ( 3-1/8" magazine ), especially in 6.5 caliber.

Hope I'm not preaching from the choir,

I would love to hear about your experiences enroute, and rationale for the inevitable decisions & compromises.

I recall your rationale for going .280AI vice the 7 SAUM had a lot to do with the 2.8" magazine, and not wanting to use an extended box, or DBM .

One interesting thing that's starting to happen is some "short" magazines are getting a little longer. The magazine on my Model 70 .300 WSM, one of the recent models made in Portugal, is the magazine box is 3.05" long.

I hope I'm playing with one before long. Not that I need it, but I gots to know!

There is talk that sometime next year the 6.5 saum will have some factory offerings!

This brings to mind an article over on LoadData about the 3" 300WSM.

I always wondered if the 3" 7 SAUM in a SA M70 WSM donor wouldn't be truly magnumificent

Inquiring minds need Leader/Reader-ship !

Certainly is not.

For those that prefer a BDL type bottom metal, GA Precision uses a 3" mag box in their 6.5 4S....

Now that George is using the .120 and the .145 throated reamers I think the Defiance XM with a mag length of 3.20 is a better choice for chasing the lands!

I've seen similar speculations but we'll just have to wait and see. Personally, I imagine if it got traction, the 65KPSI limit would see some of the mystique disolved for this cartridge. Some of these guys are posting velocities in the SAUM that make .264WM guys happy...the only way to do that with a smaller case is redlining the pressure.

I suspect it would be similar to the 7mm STW when it was made in factory form...it slowed down a LOT compared to what everyone reported in its wildcat days.

Exactly.

Becoming a viable factory cartridge in the U.S. means approval by the Sporting Arms and Ammunition Manufacturers Institute (SAAMI), made up of manufacturers who want to make sure any factory ammo is safe in any factory firearm chambered for the round. And they have yet to approve a maximum average pressure for any rifle cartridge of over 65,000 PSI.

Another possible hang-up would be consistent chamber dimensions. Different throat lengths wouldn't cut it.

All that aside, SAAMI membership isn't necessary to produce ammunition, and even compliance with their pressure and dimension standards is voluntary among members. A number of small non-SAAMI companies make and sell ammo outside its standards. There's no reason GAP can't make ammo in Hornady cases and sell it. But that wouldn't make the cartridge nearly as available (and popular) as SAAMI-approved factory rifles and Hornady ammunition.

As somebody that has only recently renewed their interest in shooting and hunting after a eight? year hiatus, I am pretty pleased to see all the interest in the various 6.5 cartridges. Would like a 264 Win to add to my 6.5X55 sometime in the next few years. If I recall, going into your LGS 10 years ago and asking about a 264 Win Mag would have garnered some funny looks.

Copper creek is already selling 6.5 Saum ammunition , I reload all my ammo so personally I would just like to see some more brass choices like possibly Lapua,but I would be happy if Remington would start making 7mm Saum brass more available not sure if they are even going to make it anymore, George said he had a couple companies looking to possible make it by this time next year we'll just have to wait and see !
Ga precision is on it's 3rd round of brass and it was suppose to drop down from $1.55 to a $1.10 but I haven't seen it, when the brass becomes a little cheaper I can see it gaining in popularity!