260, to AI or not??

[Rlbol]

About to rebarrel a model 12 to 260 rem. I am looking for some insight to the advantages of an 260ai verses regular AI?

I do reload, I have a couple hundred rounds of new Laupa 260 brass. And don't have the barrel yet.

The rifle will be used for long range steel plates as well as any competition can be used in! The only problem I see is I will also be reloading the 260's for use in an lmt mws gas gun. But I have not found any reasons the AI will not work In it once the barrel is reamed for such?

I would appreciate any guidance from anyone with experience in the AI cartridges. I have never dealt with any.
Thanks in advance!

[stomp442]

I say go for it. I absolutely love mine. I'm getting 2940 fps out of mine with a 26" tube with 44 grains of H4831sc. That's 6.5-284 territory with less powder less recoil and less barrel ware. The Ackley case has less prep work in the long run too.

[JCalhoun]

I'm under the impression that semi-autos prefer tapered cartridges to feed reliably from the magazine. Also, semi-autos need to have full length sized cases. The AI is usually a neck size only.

[scope eye]

I always hear I should have gone they with they AI chambering, but you never hear, what was I thinking having this chambered in AI,

Dean

[bootsmcguire]

To me, the added brass life and reduced case stretch are the biggest gains to the AI chambering of most rounds. I have the 243AI and have had great case life. I just upgraded my 22-250 to a different barrel in 22-250AI and I also shoot a 22 K-Hornet which is basically a 22 Hornet-AI. That case sees great gains in case life from the Improved chamber.

Fireforming loads are normally quite accurate also. In my 243AI I normally fireform in the field hunting coyotes, and I got a bunch formed when I went out west on a pdog shoot last year.

[yobuck]

im for anything that will improve performance. as for sizing why not full legnth the ai cases?
i full legnth mine and all the others i shoot.

[bodywerks]

I decided on 260 for my current rifle being built. I sent a dummy round at near mag length at 2.965 with a 140 amax. I got a call from my gunsmith yesterday and he told me that he'd have to ream the throat an additional .140 beyond the standard reamer to get that round to chamber. I explained to him my reasoning for wanting the bullet seated out that far (puts base of bullet in the shoulder area for a more efficient launch of the bullet, and it gives me more case capacity= creedmor beater). He builds mostly tactical type rifles, so maybe its not something often done on them. Regardless, he advised against it. He said he had reamed am additional .050 without issue before and that that's all he'd be comfortable doing, so i compromised.
As soon as i got of the phone with him i got to thinking that i probably should have just gone 260AI and been done with it...
Take that for what its worth.

[stomp442]

There is lots of haters of AI cartridges and I have a hard time understanding why. I have a couple of them now and everyone of them is a bad mother chicken and meets or exceeds the performance of the comparable factory offering while being more efficient.

[JCalhoun]

But do they work in gas guns?

[bootsmcguire]

I have very rarely had a load that shoots best in 2 different rifles. Going to the AI in the Model 12 and keeping the straight 260 for the gas gun would be a good way to keep your loads easily identified for which gun they were loaded for and allow each gun to work with the round that works best for its application.

Just a thought.

[Luckus]

We have two 260 AI shooters and one straight 260 shooter in our little F class group. The standard 260 has been beating the other two, although I can't remember by how much. The plain 260 guy might have a better setup or he may be a better mechanic. It's a great round no matter which one you choose. Luckus

[bodywerks]

I'm launching 140 amax out of my plain Jane 260 at 2900. Good enough for me! And that's not even a hot load (for my custom chambered 26"Krieger)- 43.2gr 4350 2.850(2.246 ogive).

[Tarleton_Texan]

Wow that is fast! Powder charge? Barrel length and twist? That's up there with 6.5x284 velocity.

[bodywerks]

43.2gr h4350, barrel is a 26" Krieger (on a savage action) and the throat has been extended by.060 over saami, but I'm currently only running 2.850oal and the load is not compressed yet. I can run 2.865 and still have a couple thou jump.

PCR/XLR/TAC338 http://i813.photobucket.com/albums/zz53/bodywerks/IMG_20130816_111453_255_zps1b498f0d.jpg http://i813.photobucket.com/albums/zz53/bodywerks/IMG_20130816_111325_951_zps290ebdd0.jpg

[JCalhoun]

MV of 2850 is where the 139gr Lapuas run best.

[calib]

i would agree with that

[mnhntr]

I do not see the benefit of 100 fps for the hassle

[stomp442]

Ackley improved cartridges are not for everybody but there is more to Ackley improving a case than just velocity gain.The fact that all iI have to do is neck size and never pick up a trimmer is a big plus. Less bolt thrust and more efficiency are also big plusses. One extra step of fire forming is really not that much of a hassle for those benefits. The fact that I can reach 6.5-284 performance while using about 7 grains less powder and still fit in a standard short action is all the reason I need and everything else is just a bonus.