What is best to buy a new firearm or rechamber an existing firearm and why? Buckfever1

A rechamber or rebarrel will give you much more choice than a new firearm purchase. You could easily rebarrel a favorite rifle that fits you perfectly and one you're familiar with.

If I had the extra flo I would like one in a Kimber or Cooper.

Don't get me wrong, if you have the desire and the means to purchase a NEW rifle then I will always say that is a good enough reason to get one.
My earlier point was just that an old friend which fits you like a glove could provide the basis for an effective and comfortable rifle with which to begin a new set of adventures in a new guise.

If you like what you have currently I'd re-barrel. If not, I'd sell what you don't like and build/buy new...


Travis

why is the 280 such a popular AI round?? from reading on here it seems like its the most popular AI. I thought it was already improved.

I could be wrong but I think it is because of, years ago (maybe still) the .280 was loaded to lower pressures with factory loads. By AI'ing and loading to normal (or more) pressures, you would see a lot of improvement. Things die slow so there is the myth. miles

Many people who build or chamber AI rounds load them pretty warmly. This leads .280 AI enthusiasts to claim they can match the 7mm Remington Magnum in a small case. And of course they can--by loading the .280 AI to higher pressures than the 7mm Remington Magnum.

Exactly why this is better than just using a 7mm Remington Magnum is rarely explained. Often the enthusiasts claim less recoil--which is BS. Often they claim better accuracy, which is natural when a rifle has a top-grade custom barrel. Rarely they claim the ability to put more rounds in the magazine, which doesn't seem to speak very well of the ability of the cartridge or the shooter.

Don't get me wrong. I have used the .280 AI and it worked very well on game, though mine was a Ruger No. 1, so I couldn't take advantage of the greater magazine capacity. But in the end I decided exactly the same thing I decided 15 years ago, after using the standard .280 for a lot of hunting over several years: The .280 AI is a great cartridge, in fact it's just as good as the .270 Winchester!

Amen to that!

Dober

I'm a .270 Winchester slut and if my new .280AI rifle is as good as my .270 700KS I'll be ecstatic.
With the added benefits of bullet commonality with my 7-08 and the wind drift advantage of the higher BC bullets readily available in .284".

buckfever1
I'd just save my pennys and look for a used M700 and build one.
A 7mm Mag will burn 6 to almost 10 grains more of powder than a 280 AI just to equal the AIs performance with 150g bullets or less.Only place a mag has any real advantage is lobbing heavy turds.
The AI
Less recoil.
Less blast.
Better barrel life.
One of Parker Ackleys favorite rounds.
Mine too.
As our friend Dober is fond of saying.
In the game fields, its ballistic "gack"
Now that 280 AI brass can be bought.
Its AI all day every day.


dave

buckfever,

That is what happens when you hang around places like this too long... Things have a tendency to rub off on you... You get to wanting what some of these guys have...

Don't feel bad, I'm no different... A few years ago, I didn't have even one McSwirley , Now look at me: I've got several... Before I found this site, I didn't even know they existed!

The good news is: If you have a standard .280 Rem, or .270 Win; they will kill anything just as dead as an A.I. You just can't brag as much about the "cool factor"... But if you can ignore what everyone else does, you'll have a lot more money in the bank... (But don't follow my lead... I'm broke!)

GH

how much compacity is gained by AI'ing the 280??

I am in the process of building my second 280AI. I always liked the 280, and the 280AI just a better package in my opinion. Less trimming, and it is the "most" 7mm you can get on a standard bolt face.

It depends on what brand rifle you want, but you could just find a 280 and have it punched out.

If 'cool' is important to you, go the 7x64 and ignore the others.

Bravo




I have a 280AI.....it's the fireform load for my Mashburn....

cumminscowboy,

About 5 grains, depending on brand of brass. If you handload the standard .280 up to the same pressure (65,000) then it comes within 50 fps or so of the AI.

Really aren't many options for just buying a factory rifle, are there? Cooper, few other semi-custom production guns? Not like you can just open up the Remington or Winchester catalog and pick one out.

Hopefully the 84L .280 AI becomes a reality, as I'd like one myself.

Do I need one, NO but I've always wanted a .280 and the AI is just the icing on the cake to me at least.

Well, that sort of seals the deal for me then. I have a Remington Mountain Rifle chambered in .280 that I have been thinking of a barrel swap to .280AI or possibly punching the factory tube out to AI. If 50 fps is what I can expect in the way of an "improvement", I think I'll just pass.

Thanks for weighing in John.

Dave

Well, in a really special .280 AI you might get 75 fps!

Blasphemey

Geee!.......

Hey, I think the .280 AI is a great round, and Nosler did a fine job of making it a commercial cartridge. But it's yet another piece of evidence that the American rifle loony loves to fill every little crevice among commercial rounds.

I still have one, by the way--a Remington 700 BDL stainless/synthetic in 7mm SAUM....

Well, how does it shoot? I'm guessing you wouldn't have kept it if it didn't?

JB as a .280AI owner I must agree with you, we loonies or "churners" do need to fill every possible gap and then convince ourselves we are getting results which the laws of physics deem impossible. I enjoy my .280AI, love the nolser brass and don't achieve anything the .270 does not, except the .270 feeds smoother.
GRF

You're right. I need one to fill the huge chasm that exists between my 7x57 and 30-06, personally !

It shoots great--but is also a "slow-switch-barrel" rifle, the other barrel a 9.3 B-S.

?????????????????????????????

The problem as I see it is the PUBLISHED (Nosler & Hodgdon) load data for the .280 Rem is limited to the SAAMI max pressure of 60Ksi. The handloader without pressure testing facilities would be hard pressed to discern when they reach 65Ksi if they choose to exceed these published, pressure tested loads.
These same companies also list pressure tested data for the .280AI and in both instances (Nosler & Hodgdon) the velocities shown are well over 100fps greater for the AI version.
So if a handloader is to stick with data published by the major manufacturers the velocities achievable with the AI version are from over 100 to over 200 fps faster.
That level of velocity improvement is noteworthy and is akin to the difference between the .300 Savage, .308 Win, and .30-06.

How does the 270 stack up against the Ackley when using 160 gr bullets ?

The .270's about 100 fps behind.

In my experience you'll get about the same velocity with 150's in a .270 as with 160's in a .280 AI (or 7mm SAUM), given equal barrel length. That's what Nosler's data suggests as well.

Not to hijack the thread here, but did you ever tinker w/ a SAUM or WSM parent instead of the 350 RM you settled on for your B-S cartridge?

The 280 AI has a lot of cool factor!

Here is mine, M700 blue printed action, Hart #5 flutted 24" barrel, Tubb recoil lug pillar bedded in a LSS stock.

She shoots too! Nosler 160 gr AB

JD338

I have had two improved 280 Remintons. Both had 24" tubes. One was a RCBS the other was an Ackley. Both were existing rifles that had been rechambered. The gain with the same pressures was about 40 fps. Those improved 280's with 24" barrles would move 140's at about the same speed the 270 Win will drive a 130 in a 22" tube which is 3125-3140.

The 7 RM will easily outrun the 280 by about 125 to 150 FPS until you get to the the heavier bullets in the 160-175 range where the magnum is faster.

I doubt that the bullet or the target knows which case pushed it out of the barrel.

efw,

Charlie Sisk has done a 9.3 on the WSM case. In fact I believe he has made a 9.3 wildcat on just about any case possible, somewhere around 20 of them.

On the subject of pressure, my former partner loves seeing velocity numbers starting with "3" followed by more digits. He was able to get his 22" barreled 270 Win to move a 130 at over 3400 fps---for one shot. Then he had to take the rifle home to get the melted brass off the bolt face and to determine if he had ruined a previously perfect rifle. His load was about 4 grains over the max load of IMR 4831. The numbers on the case head were mashed so hard there were no traces remaining. I wonder about the speeds reported by those who are a "fan" of any rifle cartridge.

Buckfever, pay little attention to Mule Deer he is having an attack of rationality. I think his loony card needs to be revoked. If we follow his thinking a bunch of rounds need to be dumped. Heck, if I wanted to be rational I'd sell most of my rifles and use the .308. What fun would that be. Get yourself a .280AI and be a loony, have some fun and look down you nose at the boring guys who shoot .308's.

I have an idea. Neck the 280 Rem case down to .277. Now that will be one for only the looniest of the very loony. It will be unique as well. It will have a little more capacity than a 270 Win. Will require handloading. Nobody else will have one. You will need to use 280 Rem brass. It will be unsafe to use factory ammo as well. WOW

A few years ago I had a really nice 24" 280AI built. It did just what you would expect that cartridge to do in that barrel length.

After the new car smell wore off I never could figure out why, since I was using a long action and a 24" barrel anyway, I didn't just go with a 7Rem or 7Wby mag.

so it appears that the love for the 280 AI revolves around 2 things, that being AI people run at max or slightly over standard pressures. couple that with pretty anemic 280 factory loadings and guys really think they are doing something if you limit yourself to the lower pressure data and a guy comes along beating that by over 100 fps with an AI, then everyone jumps on the bus.

I did some checking in my lyman 48th for 140's and 150's the top book loads are faster for the 270 despite being a smaller bore. so once again muledeer summed it up, 50fps with equal pressures.

There are a couple of small advantages to the .280 AI. The cases don't stretch much, typical of AI's, and the Nosler factory brass is made by Norma and hence excellent.

In fact, the brass is why I did my own .280 AI. Nosler gave me some, so of course I had to obtain a rifle to use it!

Well JB, I used to buy the dies first to justify the gun, result is the same but it's obvious you still have your "rifle loony" credentials. I have a M700 ADL combination gun in 280AI and 7mm Rem Mag. When I want the 7 mm mag I use my handloads and when I shoot 280 AI's thru it I buy 7mm Mag factory loads pretty trick huh? saved the die money for beer that time. Magnum Man

That might even be called anti-loony!

Did you drink the beer slowly?

As someone who has been circling the 7mm kool-aid punch owl for a while <grin>, I can report that it's the single most hotrodded bore size there is! You will see the craziest claims made for speed... WAY over what the books say.

I attribute it to the fact that the 7mm bore size naturally attracts folks who like to gack and tussle over ballistic minutia, since in many ways the 7-bore often wins those tussles.

(actually, my 2nd and 3rd hunting rifles were 7mm's ('08 version) so I've secretly been sipping the koolaid for a while now... grin...)

Yes very slowly and I only opened it after the bottle started to sweat and after it sweat enuf I drank it slowly, then repeated the process 2 more times .Which was enuf to forget about 280 AI's and went to my favorite gun shop to trade for a 280 Rem,that is a really different outfit you know?Funny thing about that St Pauli girl leading me astray and giving me ideas, illusions of grandeur as I was tipping up a bottle my eye caught the Hornady catalog laying there. Sure enuf, I opened it and Hornady Light Mag SST ammo for the 280 Rem with 280 AI performance.... only 2 guns but 3 cartridges. Go up or down to the AI without buying any new dies. More money for St Pauli girl. Magnum Man

If you shoot a 7mm magnum (or any magnum) you're tagged as a poseur but if you shoot a .280 Ackley Improved you're tagged as an aficionado!

So did you lick the sweat off The St Pauly girl??????Just wondering!!!

Where does one find 65Ksi pressure tested load data for the .280 Remington?

Or are you on your own in determining when you reach 65K?

Using only published data the AI version is 100 to 200 fps faster.

Well practical or not...seems real cool and I will have a NULA .280 ACKLEY next week. It was the same LH .280 that Boddington tested for G&A last summer. Worked out a deal with Melvin and he Acklyized and repainted it and I am planning to shoot the hell out of it. Prolly have 1500 7mm 150 gr bullets of various flavors plus a bunch of Amaxes that have been molding away on my bench and they are going to get launched.

Lefty C

I've never been called a poseur before, a hoser maybe...Ah Huntz, no I didn't but will take your advice under advisement sounds like a safer idea than what I was thinking. Magnum Man

I'm jealous.

What kind of velocity would a 7mm Magnum get if loaded to 65,000 psi? It seems only fair to load them both to the same pressure.
whelennut

Well this is how I always felt about it....I built a 7 1/4 pound 7RM back in the early 80's with a long throat that would pile composite groups;drove 140's close to 3300 and 160's at 3125....hunted and shot it till the barrel quit in the 90's.....

I also knew by then the 280 would do 3080 with a 140 from a 22" tube,and better with a 24" and RL22,because I had those, too....when I learned of John Sundra's 7mmJRS I thought it was nice but did nothing I couldn't do with a 24" tube from the 7RM, and much easier.

These days I look more to the rifle than a middle of the road, capacity wise, cartridge like the 280 imp.

When I handle a Kimber 84L I will know if I like it better than the 8400 WSM's. If it stands out handling wise I might consider one in 280 imp.

Right now I have WSM's in Kimber Montanas and 84M's as well. Can't see the 280 imp. beating out a WSM. However the rifle might.

Somehow I doubt it. Its just another cartridge.

nsaqam,

The .280 AI data in the Nosler Reloading Guide 6 was developed with the SAAMI 65,000 psi limit.

The SAAMI limit for the standard .280 is 60,000 psi, supposedly because it was designed for the Remington pump and autoloading rifles--despite the fact that both rifles were also chambered for the .270 (65,000 psi). But that's the big reason the .280 AI data shows such a big advantage over the standard .280.

Low factory pressures for standard cartridges are often the reason AI rounds show a big velocity jump, leading some innocent handloaders to believe a few grains of extra powder capacity works miracles. I have read articles over the years about supposed wonder cartridges such as the .250 Savage AI and the .35 Whelen AI, where the author compared factory muzzle velocities with (usually warm) handloaded velocities for his AI rifle.

The .250 AI does gain quite a bit of powder room, due to the tapered case of the .250 Savage, but the .35 Whelen AI probably gains the least amount of powder room of any Ackleyed round.

FWIW,

I just went back and checked my load records for my .280 RCBS Imp.- nearly identical to the AI version, 30 degree vs. 40 degree shoulder.
Rifle is a custom Ruger #1.

With my best load of RL22 and 140 gr. Nosler Partitions, MV is 3150 fps.
With factory Fed. Vital Shok ammo, and 140 gr. Nosler Accubonds, MV is 3100 fps. Accuracy with the factory stuff is as good, if not slightly better, than my handloads.

50 fps difference is just not worth the hassle, IMO.

Yes, I understand that, but where does one find 65K data for the regular 280?
If the only published data for the regular 280 is 60K how does a normal handloader reach the 65K that the AI version is loaded to absent pressure testing equipment?

The point I'm trying to make is that unless one can find 65K data, (either published or measured yourself) for the regular 280 then the 100 to 200 fps AI advantage is the reality.

The same calculus applies with regard to the 280AI vs. 7mmRM comparison.

If the published load data for the 7mmRM is limited to 61Ksi (SAAMI)then the 280AI, loaded per the published 65Ksi load data gets velocities very close to the RM.

Well, there are two ways to at least get a reasonable estimate of 65,000 psi in the standard .280.

One is to use the old ballistic rule of thumb that pressure increases at twice the rate of velocity. Thus, if we have some standard .280 data that suggests 3000 fps is tops with 140-grain bullets, we can do some figgerin' and come close.

65,000 divided by 60,000 = 1.0833. From this we can figure that a velocity increase of about 4% (half of 8.33%) should result in 65,000 psi--or even less, since most handloading data isn't right at the top anyway.

3000 + 4% = 3120. This should be a safe maximum velocity in the standard .280, given a manual-listed 60,000 psi maximum of 3000 fps.

We can also measure the difference in case capacity between a standard .280 case and the .280 AI. I've done this and IIRC the difference is about 5 grains.

Let's say the .280 holds 67 grains of water with a 140-grain bullet seated. This means the standard .280 holds about 62 grains--again a difference of about 8%. This time, however, we use the 1/4 Rule, that any increase or decrease in case capacity result in 1/4 that amount of potential velocity at the same pressure. Thus the .280 is capable of about 98% of the velocity of the .280 AI.

If the .280 AI can get 3250 fps from a 140 in a 26" barrel (and the Nosler data lists 5 powders that do that), then the .280 can get 3185 fps when loaded to the same pressure.

Now, that's in a 26" barrel. For a 24" barrel we subtract 25 fps per inch, and come up with 3135 fps. This pretty much agrees with the number we got with the other method--and is pretty much exactly what I tend to look for from the standard .280 when handloading.

Of course, that depends on the bullet to a certain extent. When I was hunting with the .280 a lot, my rifle was a custom Remington 700 by Dave Gentry with a 23" barrel. My light-bullet load was the 139 Hornady Spire Point Interlock and 60 grains of H4831, at around 3150 fps. Typically Hornady Interlocks develop a little less pressure, on average, than most other bullets, so can be safely pushed a little faster.

Thanks for the thorough explanation JB.

If I ever want to impress a chronograph I would get a Ruger #1 with 26" barrel and chamber it in 7mm Magnum.
whelennut
I'm betting a 35 Whelen loaded to 65,000 psi would leave a mark though. Just sayin.
whelennut

what is funny is I went over to nosler's site and looked at their 280, 280 ai and 7 mag data.

the 280AI lists the fastest loads of all 3, EVEN the 7 mag, the top end load with a 140 fired from the 280AI is listed as 94 fps faster than the fastest 7 mag 140 load!!!!

compared to the regular 280 the AI version has loads almost 300 fps faster with a 140.

so the myth of the 280 AI is busted!!! the reason being is people are comparing lower pressure anemic book loads to higher pressure slightly more compacity AI loads. there is no magic here.

After the 7mm Rem Mag was in the market long enough for others to load ammo, folks observed that full loads often showed pressure spikes. The result was a reduction in load maximum pressure to accommodate any potential pressure excursion.

jim

I have heard about the "pressure spikes" with the 7 RM and find it hard to believe. I can't see that it is innately worse than any other similar cartridge. We never hear complaint about the 257 Wby, 264 Win, 270 Wby, 7 STW etc.

I remember when the 7 RM was introduced. Most of the early adopters used military 98 mauser actions and 1917 Enfields. At that time the M700 was considered only a slight step up from the 110 Savage. Neither were well loved. The rifles were built by all sorts of back yard gunsmiths and there were many different throat configurations on the reamers. Hardly anything was standard. Remember those old rifle are still out there being used with factory ammo. Today most agree that a 160 @ 3050 is about all you can get with a 24" barrel. I knew guys who would add powder until they got 3200-3250 and then quit. Those loads were HOT.

The magic is that the 280AI is SAAMI certified for 65Ksi whereas the 280 is 60Ksi and the 7RM is 61Ksi.

All this means is that there is load data out there that reflects these limits and for those who are not comfortable with over book loads the 280AI makes a pretty desirable package with regard to velocity achieved per powder expended.

There's is so much truth to this.

Although it's often difficult not to pick a cartridge on on one's collective bias, more and more it seems to me that picking a bullet for the job at hand and a rifle that you like very well make much more sense.

For example, for deer, let's say a chap is comfortable with a bit heavier bullets in the 150 - 180gr range. The guy needs to find a rifle that he likes and that suits his hunting style that will throw 150 - 180gr bullets at deer-killing speeds. The cartidge, whether it's a 7mm-08 or a .300 WSM or a .30-06 or a .280 AI, doesn't really matter all that much. All will do the same job with nearly equal results.

Rick,

Actually, there is a little truth to the "pressure spikes" in the 7mm Remington Magnum. I have gotten the story straight from some of the guys in ballistic labs.

For some unknown reason, the 7mm RM's pressures do vary more than in some other cartridges. You really can't call them pressure spikes, as in all of a sudden a case blows a primer or something like that. But the pressure do vary enough, especially with certain powders, that the SAAMI pressure standards were reduced somewhat from the original levels. And that's why the SAAMI average pressure is 61,000 rather than the 64-65,000 of most other belted magnums.

John,
Before long I will need to order a 257 Wby from Mel.
Thanks
Rick

I need one to fill the gap between my 7-08 and 7WSM.

Thanks folks for all the good info folks, lots of valueable insight...me, I'm still quite happy with my 280 AI, not that I don'y also like my.270(s), 30'06 or 300 H&H's any less.... as per usual it's as much or more about the rifle...and the memories!

CC beings no one else will call your BS I will, you will duly note on page 307 of NOSLER #6 THAT 3152 FPS is the highest vel load listed for the 280.On pg 314 the highest vel load for the 280 AI is 3266fps. On page 335 for the 7 mag is 3340 fps. Even more interesting is that both the 280 and the AI version had 26" barrels while the 7 mag was tested with a 24" barrel. you want to quote gack get it right. Magnum Man

MM: Thought something was funny there.....thanks for clarifying.

So do I!

I was looking at data on the website from nosler.

65k psi how much CUP is that, and is there a way to extrapolate velocity with CUP the same way it was done with PSI in another post by muledeer.

I called Jarrett's a couple of years ago and got into a discussion with a young man who I think was Kenny's son. I asked him about the 280 AI and he said he would just get a 7RM. More velocity and simpler. He thought Kenny had done well marketing the business thru the 280 AI but he personally thought is was not the best choise. Funny.

Good grief!

The drawings in Savage 99's post above beg a few questions :

What are the implications of the .014" reduction in headspace in the SAAMI version from the Standard AI version.

Will factory .280 still fireform in a SAAMI chamber ?

Will brass fireformed in a Standard chamber fit in a SAAMI chamber ?

I ask because I have a 700KS in .280 that is whispering to me.

I had my .280 AI set up to use Nosler brass. It worked fine when fireforming from standard .280 brass.

What problems or peculiarities would result from firing Nosler brass/ammo in the longer Standard chamber ?

Thanks

Excess headspace--with the standard side-effects: possible misfires, and stretched brass with possible case separations.

Can you get a workable approximation of the SAAMI/Nosler .280 chamber by running an Ackley reamer in short 0.014"? Or would it take regrinding the Ackley reamer?

For what it's worth my .280 AI with 25" barrel is neck & neck with my 7RM with 23" barrel at least with 140 & 160 gr. loads. I know it is a fast barrel vs. a slow barrel thing and doesn't prove anything. My AI is almost free bored as it was reamed for Match Kings seated long.