260 AI loads

[ssphoger]

Ok just got a MGM 260 AI barrel for the Encore its 20" long with 1-8 twist. I want to use 120 to 140 bullets for hunting white tails.
Not finding much load data,
How much over standard 260 Rem. can I go?
Any one got any loads?

 

[Cappy]

I'm interested in this as well as I just picked up my new .260AI. So far after looking around H4831 seems to be pretty popular.

I used 44gr's of H4350 and 142gr MK's to form some brass and it worked well. Going to test it out in the formed brass to see what kind of velocity I can get, but I have a feeling it will be a little fast. I used the standard version as a guide line, starting a couple grains below max and working up in .5gr increments to start looking for pressure signs.

 

[Cappy]

Well I got out today and did a little shooting. Finished breaking the rifle in with some standard cases that needed to be fire formed. Then I moved on to some 140gr SST's over H4350 starting at 44gr then working up to 45.5 in .5gr increments. No pressure signs at all and the speeds are 2876fps out of my 23" Rock barrel. My goal was going to be 2900fps and that looks like it shouldn't be a problem. Should make for an excellent hunting load. I will still give H4831 a try.

 

[bsekf]

I have a 7-08 AI on my Encore. I start at the mid-range of listed 7-08 loads and go up to 5% over max. That is where the case starts to stick. I find the lower range loads shoot best. Have to remember the 308 family is high pressure and the Encore frame flexes as pressure get higher. The reason I go with AI for the Encore and Contender is to reduce the cartridge taper and hopefully the straighter case will grip the chamber wall reducing the back thrust and frame flex. There has been some interesting research done on this subject.

Have you had any case separation?

Bill