Interesting thread on the short mags and feeding.......seems I am not alone in my thoughts....
http://www.serveroptions.com/cgi-bin/ubbcgi/ultimatebb.cgi?ubb=get_topic;f=5;t=005779Charlie
It was an interesting post Charlie but I guess I just don't get it.....why do some have to cast aspersions on something just because they don't like it or because they think it isn't necessary. That's why they have different model cars and why brunettes can buy peroxide at the drug store.
People complained about the 308 because it wasn't a 30/06 and now they are pounding on the 300WSM and 300SAUM because they don't believe they are real magnums...maybe they named them wrong....what would the reaction be if they were named the "300 Efficient" or something similar?
And I'm not suprised that Darcy doesn't want to spend non-productive time figuring out how to make the "shorties" feed as he apparently has more than enough business without adding more potential "problems" (I don't especially like rebated rims either).
Of the recent shorties from Winchester & Remington, the one that makes the most sense to me is the 270 .... a noticable increase in performance over the 270 Winchester which was/is a great round.
Final thought ----- I'm not sure what the problem is with feeding. I have a Lazzeroni Patriot (.308) and Hellcat (.375) and both feed as well as any rifle I've owned. They are both built on McMillan MCRT actions.....one by Lazzeroni and another by a custom 'smith. Maybe it isn't the cartridges that are the problem but rather the actions they are building them on...or the 'smiths who are building them.
My thoughts very much differ,as does my action preferences.
I have rifles based upon all of the most hated designs of the CRF Fans. Those rifles are based upon the typical Ackley Improved design(minimal body taper and jaunty 40 degree shoulders),the 284Win hull,SAUM,WSM, and even the dreaded Ultra.
To the contrary,the only short mags(abbreviated H&H based chamberings),to fully yank my crank are the 257Wby and 7mmRemMags. Both exceptional.
The 300Winny is also a Good 'Un,but I'm happiest with more capacity,in that diameter,when toting an H&H full-lengthed action(30-8mmRemmag,my favorite far and away).
I eagerly anticipate weighing in with hands on testing,of both the 257WSM and 7mmWSM in direct comparisons,to the above mentioned H&H short mags.
Those chamberings scorned by Purists,simply work and very well. None of that speculation..................
I get it. It's the money! When your not sure of an answer then select "It's the money" until new facts change your mind.
The "custom" gunsmiths involved in this thread find it difficult to get short mags to feed in actions that were never made for them and are too long anyway. Every short magnum sold is a lost order for a gunsmith.
As to why a short magnum I feel that this thread expresses it best.
www.serveroptions.com/cgi-bin/ubbcgi/ultimatebb.cgi?ubb=get_topic;f=6;t=007729 Now I am a customer and not a supplier or gunsmith. My voice carries more weight. I could not care less what some ivory tower Mr. Perfect gunsmith thinks about what cartridge is for me or not.
I don't blame those on top either. I would not expect Picasso to paint me an impressionist haystack.
I don't understand all the fuss. <img src="/ubbthreads/images/graemlins/confused.gif" alt="" /> The gunsmith I use built a .300wsm for me last year on a Ruger 77 tang safety. He had to widen the box; but no other alterations needed to be made. Follower and feed rails are unchanged from factory. The rifle feeds perfectly, nary a bobble-ever! <img src="/ubbthreads/images/graemlins/grin.gif" alt="" />
Speaking of my gunsmith, he is re-boring a 20" .243 out to .358win. He told me last week that he was going to start re-boring barrels this week, so should be soon. <img src="/ubbthreads/images/graemlins/grin.gif" alt="" />
Don, I think I get it too. As Savage99 on the other forum, you don't get the answer you want so you post as Don on this forum, criticizing the gunsmith in the third person. One of the premier gunsmiths in the world offers his opinion, based on experience, yet you know better. He's spent the time to design and manufacture correctly designed mag boxes for the more suitable magnum cartridges, and doesn't see the point in the super short mags. For the record, I don't own one of Echol's rifles, but do recognize common sense when I see it.
It's not exactly rocket science that the super short mags will not, and never will, feed as reliably as the already established longer cartridges. It's REALLY simple physics, the wider the cartridge gets, and the shorter it gets, the more extreme the angles to get it to line up with the bore line. The more extreme the angles, the less reliable/smooth the feeding will be. The super short mags offer no advantage over the longer,already established cartridges.
RickF- I can only speak from my own personal experience, but I have had zero failures to feed, or any other failure for that matter, with my wsm, built on a Ruger action. You can't get any better than zero failures. Also had a 7mm Dakota built on a Ruger action. It is same diameter as the wsm, just a little longer. I have been using that rifle regularly for five years or so, again with zero problems. I don't understand what problem some gunsmiths have.
Acy, I agree some rifles will work fine, and am not saying they won't work. I will point out however, that your tang-safety Ruger rifles are push feeds, while D'Arcy Echols works exclusively with controlled feeds.
In a push feed action, the feeding is controlled by the configuration of the feed rails. Providing the shell pops out of the magzine at the correct point in the bolt's forward travel, they will feed fine as the shell is simply pushed into the chamber. If the cartridge comes out too soon it is likely to pop right on out of the rifle. On the other hand, in a CRF action the cartridge is captured by the bolt, hence the feeding cycle is much more dependent on the correct mag/feed rail/bolt face/extractor/extractor cut configuration.
I guess my only complaint with the shorties is the misrepresentation by the factories and some writers, that their performance is every bit that of their longer conterparts. This is not exactly an accurate statement when seating the longer and heavier projectiles which eat powder capacity. Handloaded, a 7mm Rem Mag will smoke a 7mmWSM or 7mm RUSM with 150-175 grain bullets. This to some probably means very little if you shoot the 120-150 grain class 7mm bullets, but it is a misnomer to say that either runs neck-and-neck with the original "seven mag" when pushing the longer heavier stuff.
The same can be said when comparing the short mag .30s to the 300 Win in the 190-220 grain bullet class. While the 220 grain is seldom used, it still may be desired along with the 200 grain bullets. The 300 Win can spit these big projectiles out much faster than their squatty counterparts.
In the quarter bore class, I would not expect to see a real difference in performance when comparing the 257 Wby and .25WSM. I believe either with 87-115 class bullets would be a holy terror on their receipients. Perhaps the shorty would give better accuracy and be a little easier on barrels.
Actually, "seating the bullets deeply" doesn't make a darn bit of difference in the short mags. If you do the math, subtracting bullet length from standard factory OAL, to see how far a 200 Partition pokes down in the powder space, you'll find that it pokes just as far into a .300 Winchester or .300 Weatherby as it does in a .300 WSM or SAUM.
Its also mostly a myth about deep-seated bullets not allowing as much velocity. The little extra space they take up isn't enough to change powder room significantly. Muzzle energy is a good way to check this. Look at the latest manuals. Nosler lists the 200 Partition at over 2800 in the .300 SAUM and 2900 in the .300 WSM. Each of these loads provides as much (or more) muzzle energy as any lighter-bullet load in the same calibers.
The reason the short mags don't match older cartridges with more case capacity is exactly that: they don't have as much case capacity. Which is why my own Sisk custom rifle on the tang-safety Ruger 77 is chambered for the .300 Winchester Magnum, not the .300 WSM.
This whole deal about deep-seated bullets hurting velocity has been written about for decades. It may have had some validity back when all our powders were huge-grained, bulky numbers like IMR4350 and the original H4831, but with today's powders you'll hardly ever see any drop-off in performance--unless you're shooting a relatively small-capacity case with a bullet almost as big around as the case itself, such as .358 Winchester or .458 Winchester Magnum.
The thing that upsets me most about the "short mags" especially the 300WSM is the words "designed to meet and often exceed win mag velocities in a short action". Or this one "this new wonder mag has noticably less recoil than my 300 win mag, it must be some freak of nature as I just can't explain it". Of course I'm embelishing a little bit, but you get my point. In my opinion these statements are crap, but everyone seems to be on the bandwagon. Granted, performance difference between the 300WSM and 300 win mag is moot <img src="/ubbthreads/images/graemlins/grin.gif" alt="" />(sorry John,couldn't resist, but attach whatever definition you will <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />). And as to the recoil, the freak of nature is between our ears and is somewhat greyish/pink in color. I personally can't tell the difference. It really makes me wonder sometimes how much thought and research actually goes into writing an article for X magazine. Maybe I'm just sick of hearing about it, but for me I will be shooting cartridges with a belt for a long time. John, I appreciate your candor.
Chuck
Mule Deer,
I will kindly disagree in part and point to the facts on the development of the 7mm RUSM, which is held to around 2.8" COL in a Remington SA (Rugers allow longer COL). Rem needed a new bullet designed especially to take into account the seating depth of the 160 grain offering (the Ultra Core-Lokt). The reason for the design was solely to try and boost the velocity to come close to the 7 Rem Mag with 160 grain bullets. And it will with the UCL bullet. The reasons are quite simple, the bullet is shortened with a reduced ogive taper unlike the longer, sleeker 160 grain Speer, Barnes, or Nosler, it does not penetrate into the powder column as deeply.
Remington new they could not offer a standard bullet from a main manufacturer and still make a proper comparison to the old 7 mag.
It gets much worse if you try and load the long 175s, you would cut into the powder column much more drastically to hold to a 2.8" COL in a Rem SA than you would in any 7 Mag LA. If you were going to shoot the short mags and wanted the highest performance achievable, you would be better served shooting the Ruger action, which allows a 2.9" COL or a Win, which allows a solid 3" COL. Can't do that with a Rem. They developed the special UCL bullet because of seating depth to powder capacity aspects, and its well documented.
Chuck....there's more than one short-30 and it will certainly run past 99% of the 300 WinMags I've been around (similar barrel lengths of course) and that's the Lazzeroni Patriot.
Mine has a 24" barrel and I can easily pass the velocities of the Winchester, either regularfactory, special high-energy or reloads and I don't need to use undersized and specially lubed bullets to do it. I load it with 165gr and 180gr bullets.....if I want more bullet weight I just step up to the same case necked up to .375. Mine has a 23" barrel and will do 2600 fps with a 300gr Nosler Partition but I typically load it to about 2540 fps 'cuz I don't like the recoil at 2600 fps....it's only 200 ftlbs difference in muzzle energy but a lot lighter on the shoulder.......by the way, the case-head size is 0.578" and they both feed perfectly.
Where did you get the info about the UCL? It sounds good but doesn't hold up. There simply isn't enough difference in the length of those 160-grain bullets to make any difference at all. You're talking maybe 2 grains of of powder capacity at most.
Plus, Remington does indeed load the 160 Partition in the 7mm SAUM, at velocities very comparable to the 7mm Remington Magnum. The reason they can do this is that the 7mm Remington Magnum has been somewhat downloaded over the years, because ballisticians found it was one of the touchiest cartridges around. Pressures commonly jump 8000 psi or more--with the same bullet and powder charge. So they had to ease it back to keep the "spikes" under SAAMI max.
As for the 175 taking up more powder space in the 7mm SAUM than in longer magnums, let's to do the math. I just measured a 175 Partition the other day and recall it was around 1.35" long. Let's seat one to maximum factory OAL in a 7mm SAUM and a 7mm Remington Magnum:
OAL Length to base of neck Bullet intrusion
7mm SAUM 2.825 1.724 .249
7mm Rem. 3.29 2.229 .289
So you see the 175 Partition takes up somewhat MORE room in the 7mm Remington Magnum than the 7mm SAUM.
Nosler's latest manual lists the fastest load with the 7mm SAUM at 2851 fps with the 175 Partition. This is 9 fps below the standard SAAMI max with the 175-grain bullet in the "regular" 7mm Remington Magnum. It doesn't look like the short mag suffers too much from all the bullet inside it's case.
Sorry to go on at such length, but I just did a bunch of research on this subject. Among other things, I found that maximum velocities with 175 spitzers in the .284 Winchester always hover right around 2600 fps with bullet seated to SAAMI OAL, no matter whether it's a "short" 175 Hornady Interlock or an extremely long Barnes X.
The reason for all this is that velocity only increases (or decreases) at 1/4 the rate of case capacity. Seating a 7mm bullet even .25" inch further out only gains about 6% in case capacity in a 7mm SAUM. This amounts to about 1.5% in extra velocity, or about 45 fps in a typical 3000-fps load. Seating a bullet .10" further out result in about 20 fps.
We've been believing this "seating-depth" myth for so many years we've forgotten to ask if it's true.
DB Bill, with the Lazzeroni magnums, we're talking a whole new animal. I don't disagree with what you are saying, but the Lazz's that best 300 win mag velocities have greater powder capacity. But to say that the 300WSM will meet or exceed 300 win mag performance using less powder is in my opinion pure folly and misleading if not an outrite lie.
Chuck
Comparing apples to apples, I believe Mule Deer is saying that the "case" capacity of the 300 WM is larger than the "case" capacity of the 300 WSM and the 300 SAUM and with the "same" bullets and all else being equal, it will out perform them because of the larger "case" capacity. I believe that, too, but I still want a 300 WSM and a 300 RSAUM to play with. They will kick slightly less in rifles of equal weight but, also yield accordingly slightly less velocity because of the lesser "case" capacity in equal barrels. I do not expect them to equal the performance of my 300 WM. The differences are about 5 grains less in the 300 WSM and about 7.5 grains less in the 300 RSAUM. I think they enhance the sport and allow for more choices which is part of what American consumerism is about. I think the 300 RSAUM is middle ground between the 06 and 300 WM and can be had in a more compact package, but it may not make it commercially. The 300 WSM probably will.
I think you are missing my point while making my point at the same time. I also say do not expect a discernable difference in recoil.
Chuck
I know what you are saying. I just WANT one, an excuse to buy an additional and different rifle.
Boss,
I'd be careful with that "want" thing if I were you. <img src="/ubbthreads/images/graemlins/smile.gif" alt="" /> That can get out of control if you don't keep a tight rein on it. Look at me - I am a case in point <img src="/ubbthreads/images/graemlins/smile.gif" alt="" /> ! Cheers - the9.3Guy
Mule Deer's right... my 300 WSM, with max loads and the bullet seated for an OAL of 2.820" still has more room for powder... what's the worry about seating the bullets deeply if there's even more room for powder...???
BA
Chuck.....you missed my point. Both of my Lazzeroni cartridges are "short" in fact they are shorter than either the WSM and SAUM. They are, however, fatter and they do hold less powder than either the 300 Win Mag and 375 H&H.
I do believe the concept of more efficient burning of the powder takes place so less powder can produce similar velocities if used efficiently.
Mule Deer
I know where Rossi got his info re: Remington's UCL bullet. It was from JRS your fellow scribe at Rifleshooter. I read the same article where JRS said that was how the SAUM for same weight bullets could equal the WSM velocities with 5% or thereabouts lesser case capacity. (ie. he referred to 'smoke & mirrors' if I recall correctly as Rem used the shorter UCL bullet & Winchester used the Failsafes which are longer to achieve nearly identical velocities).
Very interested that you have debunked this seating depth issue as a myth. Be very interested to read your article when it is published. BTW really enjoyed "Optics for the Hunter". Helped a lot in making my choices & learnt to test things myself rather than take what some old Pro said about Kahles or Pecar scopes' light gathering ability. Again some myths there.
I was really taken aback by your comments on the 7mm Rem. I have just started to reload for it. Can you please elaborate on these 8,000 psi spikes. Is it only an issue with certain powders only (I'm using AR2217 also known as H1000) or an issue with the cartridge generally.
I have not heard that the 7mm Rem was anything other than "reloader friendly"? We amateurs have no way to reliably measure pressure so we have to rely on the professionals to publish the correct information.
Regards,
JohnT
The pressure spikes with the 7mm Remington Magnum do tend to occur with some powders more than others, but it's a problem in general.
Many shooters on this forum probably don't remember (or weren't born) when the round first came out in 1962, but the original factory ballistics were 3260 with 150's and 3070 with 175's, velocities that are barely exceeded by the 7mm STW today. Of course in those days few hunters owned chronographs, but independent tests showed Remington came pretty close, especially in the 26" barrels standard for factory testing back then. This was with IMR7828, which was developed for the cartridge. The round was hailed as the new Wonder Cartridge of the century.
The pressure spikes weren't discovered until the industry changed from copper-crusher pressure testing to the more senistive piezo-electric method. The standard SAAMI max velocities were then dropped to where they are today, 3110 with 150's and 2860 with 175's. These are taken in 24" barrels. They will still do any job that needs doing but are a long way from the original specs.
The data in loading manuals reflects this. Any pressure-tested loading data takes into account pressure swings, the reason you never see pressures of any load right up at the maximum SAAMI limit for ANY cartridge. This is why the max average SAAMI standard for the 7mm Rem. is only 61,000 psi, as compared to around 64-65,000 for most other magnums. If you stick to published load data and don't try to turn your 7mm Remington Magnum into a 7mm STW you'll be fine.
The same phenomenon occurs with the .243 Winchester and 100-grain bullets, though not with varmint-weight bullets for some reason. This is why the .243's factory velocities are so much lower than the 6mm Remington's even though there isn't that much difference in the case capacity. The .243's original factory velocities were also dropped considerably when piezo equipment became common.
This comment on the 7 mm Rem Mag being a "touchy" cartridge leaves me with doubts. If it is so I would like to know why? There are some ballistic experts on this internet including Ken Howell and maybe others and I would like to hear how and why.
My experiance with the 7mm Rem Mag is long but narrow. I got one soon after they came out and I loaded it to it's max and I have the chronograph and head expansion data to this day. Then I got another one in 1969 and shot it until the barrel wore out. Almost all of this shooting was done with the keg of surplus 4831, various primers and conventional bullets. Never did I see any pressure spike.
I don't see the 7mm Rem Mag as being any different that many other cartridges like it. It's not overbore capacity nor is it a pioneer in it's general expansion ratio or other aspects.
Another smith has written that he has seen more blow ups with the 243 Winchester than any other. Again he was not specific however on that cartridge I have read that some necks have been thick enough to interfere with some tight chambers.
I am willing to learn something new every day. Most of us ask why when we hear something.
If the resonse is "It's one of those unexplained mysteries" then I have even more doubts and I am capable of getting scientific. To lead this in that direction I offer a fact from the field from mechanical failures. "The most common cause of mechanical failure is improper assembly"
While that seems general it's an effort to narrow this down.
JRS is one of the True Believers in seating bullets out. In fact, I believe he built a .300 WSM on a Ruger 77 '06-length action before the factory rifles were even out, so he could "seat the bullet out to the lands." If his gunsmith used a factory reamer, JRS was in for a surprise, as the lands in the .300 WSM start right in front of the chamber. There is no "throat" as we tend to define it.
This whole thing happened already. When the .284 cam eout a bunch of gun writers got incensed that it wasn't chambered in the Model 70 Winchester so the bullets "could be seated out where they out to be." Several built .284s on various '06-length actions at great expense, when they could have just gone down to the local store and purchased a .270--the cartridge the .284 was supposed to duplicate in short actions.
My piece on deep-seating bullets wil appear in HANDLOADER in a month or so.
I got the information about the 7mm Remington Magnum from the ballistics boys while touring the facilities of two companies, one a powder company and the other one of the Big Three ammo companies. The phenomenon is well known in the business.
You're not going to see it in the average rifle with published data, because they've made sure you'll be well below any pressure level where a problem might occur. I got the info about the .243 from the same sources. I've since talked to ballisticians from other companies who confirmed the information about both rounds.
If you want, go ahead and call a few of them. If you can find a copy, you might also check out A-Square's loading manual and the pressure spreads with the 7mm Remington. That manual is one of the few public sources that quotes pressure spreads along with average pressure.
None of the professional ballisticians I've talked to has any firm explanation of the phenomenon, though some think it's related to the angle of the shoulder and short necks. But nobody has any proof. By the way, I've talked to enough of these folks to know that there are some things they CAN'T explain. In fact, most labs talk back and forth a lot when they run into problems, helping each other out. They're all gun nuts to one degree or another!
Mule Deer.....the "problem" of short cases and seating depths is something that a lot of folks seem to have a problem with and I look forward to a full article on it but I recall you writing clearly about this non-problem on more than one ocassion.
I guess if Jack O'Connor didn't say it it can't be true. <img src="/ubbthreads/images/graemlins/wink.gif" alt="" />
Another touchy cartridge is it's 1/2mm skinner cousin,the 264.I find it is interesting the why of the downloading ,better measuring.
And the answer once again is....
.270/.30-06! Tall and straight like Gary Cooper. They feed well, shoot well and don't kick to speak of. Bullets do not protrude into the powder space but conversely can be seated out to reach the lands in SAAMI spec chambered rifles. They offer no reloading surprises. They are within an inch of anything's trajectory within the ranges where 99.347% of all game is shot, and are within 3 inches of anything's trajectory within the ranges wherein 99.752% of game is shot. They just get the job done with a minimum of fuss. Ta-daaa!
I know, I know - Bore-reeng.
Sorry, just being a smug smart-a**. <img src="/ubbthreads/images/graemlins/wink.gif" alt="" />
Mule Deer- Like JRS, I too, built a 300wsm on a Ruger long action as soon as reamers became available. I had it throated long and tight. Using Re-22 (I am at my office and do not recall how many grains), Fed 215 and Barnes 180xlc seated to 3.15 oal, I get 3125fps. Barrel is 25". Load is near max, but as some of my cases have 11 loads through them without problem, I don't think I am skating on too thin ice. I do wish I had a means of measuring actual pressure. I am not capable of doing case head measurement with any accuracy. I could measure the same head 10 times, in the same place, and get 10 different readings. I know it wouldn't measure actual pressure, but if I could get it to work, it could help see somewhat where I am.
Jim, you might not have too much of a future in firearms sales <img src="/ubbthreads/images/graemlins/grin.gif" alt="" />
Personally, I view the short magnums as nothing more than a marketing idea. Lets face it, the manufacturers need things to sell. They are in the selling business not the "gun" business. They constantly need different products to crow about in the gun rags to keep their business viable. I have never shot one of the new short mags and frankly, don't particularly care if I do. Reduce the action length by about half an inch and save 4 ounces. The gun should recoil more, right ? Sure it should. Add more powder to the case and the gun should recoil more right? Sure it should. Speed the bullet up and gun should recoil more right? Sure it should. What the heck have you gained here except marginal increases in bullet speed at the cost of more recoil? Now make the gun lighter and you get even more recoil with virtually the same velocity as the old 270 Winchester. I am getting velocities similar to what John B. reported in his article about the 270 short mag out of my old 270 Winchester ! Perhaps one might get just a smidgen better downrange ballistics due to 100 fps additional velocity but even most of this will be in your imagination and not a realistic advantage under field shooting conditions. Gimmie a break, here guys. No sir ree Bob, a marketing ploy. I'll keep my old 270 Winchesters. By the way, John, I enjoyed your article on the 270 short mags. Very informative.
We cannot see in to that violent explosion that occurs on ignition in the 7 Rem Mag or any other cartridge so the cause may not be verifiable but the resulting pressure spike is. When this many say so and do not say it about other cartridges, I listen just as they, also know some powders produce spiking they cannot yet understand. It continues to be one of my favorites regardless.
Feedback like this when it's does not come with numbers, dates and specifics is hot stove fuel and very interesting that it is.
I could point out that the 7mm Rem Mag and the 243 Win have short necks and that the heavy bullets protrude way into the powder space and then we would be chasing our tails.
I have worn the barrels out on 243's but all with varmint bullets so again I can't report any pressure spike with those loads. Also my 7mm Mags were shot with very few 160 SBT's and none longer.
I have a friend who is engineering mgr of one of the worlds biggest mfg companies. He does not put up with mysteries well.
However he has not figured everything out either. It's just that he and I believe that there is a specific answer for it and that's if the problem were even well defined here which it is not.
Here is a link to the scientific method
http://phyun5.ucr.edu/~wudka/Physics7/Notes_www/node5.htmlI offer this only in good humor and ask for instance for more data. For instance do the pressure spikes occur only with long bullets in the 7 mm Rem Mag?
Mule Deer
Thanks very much for that additional info. Geez you learn an awful lot on this forum.
Unfortunately, I gave up my subscription tn Handloader & only subscribe to Rifle now. Which issue no# will it be & I will get a friend in US to buy the issue.
I never saw velocities as high as that for the 175gn for the 7mm Rem. And you are right I was still in daipers then. My rifle is a Ruger No. 1 with a 26 inch barrel & I have no difficulties getting chronographed velocities the same or slightly more than published. So I don't tend to push it as everyone's opinions on pressure signs vary so much. Also I have read an interesting article where the really useful gains in velocity in "improved" cartridges and wildcats were due to loading to higher pressures than base cartridge. ie. no free lunch, you need cubic capacity.
Speaking of factory ballistics though, I do have an issue with the Win Supreme 270gn Failsafe .375 H&H ammo. Out of a 24 inch barrel it only chronographs 2550 not the 2700fps claimed. It does slightly less in a friends 23 inch barrelled Ruger. Is this being downloaded for safety reasons as well?
JB's point on the 7 Rem mag is hardly new news. There is a reference to this in Speer #13 (pub 1998) I can also recall mentions of this going back well before that.
Many of us "want" our favorite rifles or cartridges to deliver some arbitrary velocity that we set our hearts on. This is of course especially true with wildcats. (Rember the 7-08 AI thread).
With this goal in the back of our heads we go out and load it till we get there. Our chronographs say the right thing, our rifles "ain't blowed up yet" and we are happy. But we really don't know the pressures, and our best amateur efforts at pressure guessing are wildly innacurate at the best of times. Hence IMO, when the powder companies and loading manual publishers (who DO test pressures) back off on a cartridge, it's usually for a good reason.
For whatever the reason, the evidence seems to be out there and well established on the 7 mag and the 243. We amateurs would be well advised to err on the side of caution.
(Nobody has ever been able to quantify the exact reason for "fast or slow" barrels, but we all know that the phenomenon exists)
JimF
Rolly,
To paraphrase the good Dr:
Point 1: Some poeple will always jump on the bandwagon of anything that is the latest and greatest. I think they are seduced by the "hype".
Point 2: Some people will turn up their noses at the "hype" and stick with what has always worked. Porbably because it is "proven"
Point 3: Some folks are always looking for new things to experiment with. (That would be me)
Point 4: Classics have a way of coming back around when you least expect them. (Good things refuse to die)
Point 5: Some people will be attracted to anything just because it's "different".
Personally I think the WSM's and the RSAUM's are a passing fad. Probably the "ultra's" too. I will make a non-scientific prediction. I think the Remington SAUM will die on the vine. I think the .300 WSM will be around for a long time, and probably the .270 WSM to a lesser extent. I think the 7mm WSM will probably die a slow death, and that is sad because it is probably the best and most useful of the bunch.
The Rem. Ultra Mags? I don't think they will ever achieve more than a niche. Probably long after I'm history, hunters will still be confidently taking game with the .30-06, .270 Win. and .300 Win Mag. <img src="/ubbthreads/images/graemlins/smirk.gif" alt="" /> Cheers - the9.3Guy!
Don,
I do not have a clue. If it is random and cannot be consistently reproduced in the lab, then it is speculation as to what is causing the spike. I have read this about these 2 cartridges for some time. Since I like and have used the the cartridge so much, I would like an answer myself.
9.3,
I too think the RSAUMs will pass away. One or two WSMs are likely to fill a niche, and I think the 300 and 338 RUMs will last.
Blaine
Blaine,
Don't get me wrong, I don't have any problems with the traditional belted magnums. I just bought a Win. M-70 in .300 WSM and a Remington M-700 AWR in .338 RUM. I just want to find out for myself what these are all about and capable of. - the9.3Guy!
Don--
Perhaps a more accurate term would be "wide pressure swings" rather than spikes. It seemingly occurs with about every hunting weight bullet in the 7mm Remington Magnum.
In general, the labs expect maximum pressure swings of 2000-5000 psi with most cartridges, but of course look for the lower as a sign of a consistent load. It's pretty easy to find this sort of spread in most cartridges.
But the 7mm Remington Magnum will swing 8000 or even 10000, and often after several identical rounds have stayed within 4000 psi of each other. And oddly enough, the 7mm STW, which has the identical shoulder angle and short neck, doesn't show the same swings! This indicates that the shoulder angle/short neck theory probably isn't correct.
The problems with the .243 don't show up as much until the throat becomes a little worn--and again, only with bullets in the 100-grain weighr range. Once again, they don't know why.
Despite all this, the 7mm Remington Magnum and .243 Winchester have reputations as accurate cartridges, at least among hunters. I have used both a lot with excellent results. But nobody picks them as target rounds, and the erratic pressure swings are one reason. Oddly enough, if you neck either case up a little, to .30 from 7mm in the case of the magnum, and from 6mm to 6.5mm in the case of the .243, the problem goes away. Why? Nobody knows.
If you do some math with one of the loading manuals, you'll find that almost any "modern" cartridge shows some bullet protrusion below the neck to various degrees. The 200-grain Partition in the .30-06 seats almost 2/10ths of an inch below the neck, yet nobody complains about it. Same deal with the 175 Partition in the 7x57.
The big difference between these and most magnums is that, in the magnums, there's a lot more powder space left AROUND the base of the bullet than in the standard cartridges.
Acy--
You're probably OK. The latest pressure-tested handload data for the cartridge indicates you can approach 3100 fps in the standard magazine anyway. Nosler lists 3082 with IMR4831 as their fastest load, but in a 26" barrel.
Miking cases doesn't work worth a hoot. I did some research on this last year, first working up loads using all the standard home-grown indicators from bolt-lift to miking, in a .22 Hornet, .270 Winchester and .30-06. Then I had the identical loads (brass, primer, powder and bullets all from the same lot) tested in a lab. Sometimes miking worked OK and sometimes it was absolutely useless--probably because brass varies from brand to brand in hardness, head thickness, etc.
I also found out that many common indicators of high pressure don't work so hot. One load that caused very sticky bolt lifts tested just fine in the lab, while another that worked slickly in my .270 was 2000+ psi over SAAMI max!
A much better indicator is your chronograph. If you're getting so much extra velocity from a given case that it seems unreal, it probably is. You're probably right at the top safe velocity for a "long-seated" .300 WSM.
I posted this question about wild pressure swings at AR and Jack Belk commented that he has found that the 243 Win has blown up more rifles than any other cartridge and that's excluding obvious mistakes such as overloads and plugged barrels.
I have used the 243 Win with for 200 yard competative target shooting with success and so has David Tubbs who won the national championship with a 243 Win. However I used only short bullets as I previously reported. The 7mm RM also won the Wimbleton Cup but those cartridges could have had special throats.
You need at least one reactionary post in this discussion, here it is, if I can't get within 200 yards so I can shoot it with a 220 grain softpoint in a Krag with a Lyman 48 I won't pull the trigger.
Miki--
Kind of off the subject but well put, Miki.
My own .30-40 is a High Wall with Axtell tang sight. It is also deadly out to 200, if I do my job! Doesn't rip up meat like the mangle-ems either. I am also partial to the .300 Savage. Have two, one with 2x Noske scope for "long shots," the other with Redfield peep.
In regard to measuring case heads consistently, for a quick check at the range I recommend what is called a thickness "Snap gage"they are Graduated in .001's you set nominal size and the gage snaps on fired case to show + or _ on indicator, the case can be rotated also to show out of round. In the shop it can be done easily to 50 millionths. They are avalible from Travers tool co .(ttc.com), Rutland and others, I think maybe Brownells may have them.