280 to 280 AI

[crabo]

Can this be done with just a reamer, or does the barrel need to be set back to make it work? SS Remington 700

Who would be good to rent a reamer from?

Thanks

[swheeler]

To make it work like Ackley intended the barrel needs to be set back

[crabo]

That's what I wanted to know. What's the general consensus? Worth it?

[swheeler]

If I was to do another AI cartridge 280 would probably be the one, K Jarrett is rather fond of the round.

[B R Shooter]

To make it work like an Ackley, where the case must crush at the shoulder to fireform a factory loaded case, then setting it back is better. If you approach this as fireforming a wildcat cartridge, then you could run the reamer in to the shoulder, and fireform. No set back needed.

People get so worked up over this. Simply fireforming with a bullet seated long with a good case grip, and you have a formed case. That .004" longer case will never be an issue in the reloading dies.

The most common example of this nowadays is the Dasher case. We are talking a full .100" for shoulder move, not a mere .004".

[nanuk]

or start with a 7mm08 barrel to rechamber... no setback needed

[swheeler]

To make it work like an Ackley, where the case must crush at the shoulder to fireform a factory loaded case, then setting it back is better. If you approach this as fireforming a wildcat cartridge, then you could run the reamer in to the shoulder, and fireform. No set back needed.

People get so worked up over this. Simply fireforming with a bullet seated long with a good case grip, and you have a formed case. That .004" longer case will never be an issue in the reloading dies.

The most common example of this nowadays is the Dasher case. We are talking a full .100" for shoulder move, not a mere .004".

BRS:Only problem with that anolgy is that the head to shoulder gets .107"longer and the neck actually lengthens by .017"(using the now SAAMI spec Nosler submitted 280AI) so headspace datum line may only move difference between go and no go but to clean up the chamber the very least headspace will now become .017" but more likely .019-.020, very few factory rifles are set min hs. I would rather have one set up just like PO intended, but being a handloader I can make either chamber work, ones a wildcat and the other is an Ackley improved chamber. my .02

[B R Shooter]

I have done this same routine on 257AK cases and not had the excessive stretch you are referring to. But maybe the 280 is different. Dasher cases stay fairly close to length, but there are many different reamers for them out there, case length must work with the chamber.

[swheeler]

Since the new neck is longer but the cartridge/chamber length is the same, if you just ream to touch the .375" datum line(maintain existing headspace)then you have .017"(at the very least) at the base of the neck left the original 17*30' shoulder angle instead of the new desired 40*. To clean that up you have to ream to depth of original shoulder/neck junction position, which remember is .017 deeper than new shoulder/neck, you now created .017" headspace. The last I did was in fact 257Rob AI, great little cartridge, and so for the 7x57AI. I'm probably on the opposite side of the fence concerning what most say about the 06AI, I like it. The 450 Watts AI I couldn't tell you because I'm not up to finding out what it is capable of, 100 grs of powder and a 500 gr bullet appeared to be mild from reading brass/extraction signs, but I am sure it would kill a dear or elk just fine.

[Doc_Stihl]

I've read from several sources that the 280AI has just about the best performance increase over factory of any cartridge.

[swheeler]

OK Doc you're talking me into it, stop that now!

[dk17hmr]

Do it properly and set the barrel back....or better yet buy a new barrel blank. Hard telling where it might end up might as well make it work with ammo you can buy at the store.

280 AI is high on my list. I love my 280. When I do build a 280 AI I will probably set it up as a heavy long range rifle.

[izzyjoe]

I've been searching for a cheap 700, or 70 action to build a 280AI. I run across one few months back, but I'd already spent my funds on something else. I'm thinking about a 26" barrel with a 1-9 twist to stabilize the heavy's. One of these days!

[leftiye]

I picked up a Rem 700 7mm Rem. mag on Gunbroker for about 400. Gonna make a tight twist 264 mag out of it. Fills the same bill for me. I've got a 280, have liked them since I was in high school (early 60s). My first custom rifle was a 6mm AI which I designed the ctg myself, then found our that P.O. had already done. I've got nuthin' agin' wildcat or improved cartridges. But if you want a magnum, get one.

[B R Shooter]

Since the new neck is longer but the cartridge/chamber length is the same, if you just ream to touch the .375" datum line(maintain existing headspace)then you have .017"(at the very least) at the base of the neck left the original 17*30' shoulder angle instead of the new desired 40*. To clean that up you have to ream to depth of original shoulder/neck junction position, which remember is .017 deeper than new shoulder/neck, you now created .017" headspace. The last I did was in fact 257Rob AI, great little cartridge, and so for the 7x57AI. I'm probably on the opposite side of the fence concerning what most say about the 06AI, I like it. The 450 Watts AI I couldn't tell you because I'm not up to finding out what it is capable of, 100 grs of powder and a 500 gr bullet appeared to be mild from reading brass/extraction signs, but I am sure it would kill a dear or elk just fine.

Great numbers, but done right, you only have .004" difference to deal with. That is the difference between a parent case go gauge and an Ackley go gauge. And that .004" figure is as assumption of the brass thickness. I have easily felt the difference between pieces of brass when fireforming which is the brass thickness differences closing the bolt. Never had cases stretch out as you say. To each his own. There are many things to deal with when forming "true" wildcat cartridges. The Ackley is a point and click wildcat that is intended as a no-brainer.

[swheeler]

Uh huh cheeeeeeese

[leftiye]

Even taking wheeler's specs, the non- set- back chamber would be useable, and easily doable. A little taper in the chamber which you might or might not size down (or you could open the size die a bit) each firing woudn't seem to be much of a problem. Especially if you neck only sized.

[swheeler]

Even taking wheeler's specs, the non- set- back chamber would be useable, and easily doable. A little taper in the chamber which you might or might not size down (or you could open the size die a bit) each firing woudn't seem to be much of a problem. Especially if you neck only sized.

I guess anything is "doable" the point I was trying to get across was without reaming to past existing headspace datum line(shoulder as BRS calls it?) you have NOT cleaned up the old chamber, at the very base of the neck you still have the original shoulder angle, now it may be small distance but its still there. You have created a wilcat that has a chamber with 2 shoulder angles, 40* most of the ways and the last bit before the neck/shoulder junction is still the original angle of parent cartridge. Then he says I reamed it this way and don't get any of the excess stretching you're talking about DUH, you never finished reaming the Ackley improved chamber! Ever wonder why Ackley him self set back one thread to ream?? I'd draw a picture BUT I DON'T THINK IT WOULD HELP! Crabo you want one have it done right, you won't be sorry

[crabo]

i've always done things right when I do them. I have a SS 700 with a synthetic stock. I always hated the stock so I put a B&C Medalist on it. I have a 30+ year old Vari-X III on it and was thinking about a new scope and a rechamber.

I would always rather have a tricked out, great shooting gun, than 2 or 3 stock guns.

[swheeler]

i've always done things right when I do them. I have a SS 700 with a synthetic stock. I always hated the stock so I put a B&C Medalist on it. I have a 30+ year old Vari-X III on it and was thinking about a new scope and a rechamber.

I would always rather have a tricked out, great shooting gun, than 2 or 3 stock guns.

A man after my own heart, good for you!