260 Rem AI ?

[Freezer]

    Is there such a cartridge (260 Rem AI)  would the added case capacity improve the performance?  My brother is having a new barrel put on a rifle and it will be a 20" 260 Rem.  He asked me the question and I just can't answer it.

[Nobade]

Sure there is, it's very popular for sniper matches having been used by Terry Cross to win most of the bigger events. It'll give you 100-200 fps more than a regular 260, out of a 26 inch barrel. I don't know what it would do in a 20 incher, that's mighty short for something with so much powder in such a small bore. But anyhow, the cartridge does work well though it mat be a little tougher to get it to feed smoothly depending on what action he's using. If he gets one just make sure the gunsmith understands how to set up an Ackley cartridge. Most I run into don't and the users have headspace problems. That bolt has gotta be a hard crush fit on an unfired factory case the first time.

[roper]

Normally the added case capacity on an Ackley  just adds more velocity and  I also would hope the groups would be better over a factory barrel but you should see that even if you don't do the Ackley.   All my Ackely rifles have 24/26" barrels my only concern is the 20" barrel, if I was building a rifle like that I'd use a Broughton 5c barrel  the added gain in velocity using that barrel at 20" might be the same as going with an AI.  The owner of Broughton barrels is Tim North and I sure be giving him a call http://www.rifle-barrels.com/.  

[EsoxLucius]

A 6.5x284 would be far more interesting and brass is available.

[Nobade]

Yep, far more gunpowder as well. If you want one, that's fine. But you're not going to go and buy ammo off the shelf at your sporting goods store, and the barrel life is about half of what it is with a 260 AI, all for another 100-200 fps. We've tried them for the tactical crowd, and in a match where you have to fire fast and hot the barrel can be toasted in one match. Usually we're getting 6 months or so out of a 260 barrel under the same conditions. But for a hunting gun where you want speed, yeah I'd do a 6.5X284 as well.

[Freezer]

    My brother fell in love with a pretty Arisaka sporter I had.  It was chambered in 6.5-257 but the barrel was shot.  It has a birds eye maple manlicher stock that he refuses to change so it will have to stay wtih a 20 in barrel.  That said the 6.5-284 is not a good option.  The 260 works well in a short barrel but he was woundering if the 260 AI would improve the performance enough to justify the expence.  My opinion is no.  At best from what little I found you gain 100-200fps.  Zeroed at 200yrds 260 AI only flatens the trajectory about 1in at 300yrds.  I can't find information on the terminal energy.

[Lone Star]

The usual gain in velocity with an AI version is 75-100 fps.  Sometimes a bit more, sometimes a bit less.  The few exceptions are cases which had a large amount of taper originally, like the .250/3000 and the .25-35.  Getting an extra 200 fps usually means loading to higher pressures than the parent cartridge.  Don't guess, check out the Nosler manual and see what really  happens with both cartridges held to equal pressures.


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