2.860 is your max cartridge OAL not your max case OAL. Max case OAL is 2.100 max. with a trim length according the lymam 49th edition of 2.090. This is the SAMMI specs. If you go by the published SAMMI data in your reloading manual your reloads should fit all factory chambers in your caliber(using new brass). I havent been doing this but about 18 months myself. I still have a lot to learn Ive got 3 of my factory rifles shooting sub moa and have 2 more I have to work up loads for. I use
this site as a resource and it is a very good one. Before I started I read a lot of reloading manuals. I read the lyman 49th first then hornady then nosler then lee and then ABC of reloading. Safety was my main concern. Alot of info was repeated in each manual but each always seemed to have something that I hadnt read in the other. I borrowed a couple of them didnt buy all of them. I go to the reloading forum on this site reading post of problems people are having and reading the solutions the good folks on here post. This helps alot. Well so much for my rambling. I do have a load for you that works well for me in my 7mm wsm ruger mk77 mk 2. According to the lyman 49th the suggested starting grains with IMR4831 is 61 gr, The max load is 67 gr. Noslers manual says 61.5 starting gr and 65.5 max . Each manual seems to vary a little bit. The load I use is Imr4831 65 gr, 140gr accubond, win case,win mag primer, my case OAL is different than sammi specs I measured the chamber on my gun, same with cartridge oal. Just use your manuals sammi data for cartridge OAL and case OAL. This shoots .60" 3 shot group at 100 yds
in my gun. Start out low and work your way up to 65 gr. Dont have a chronagraph by the lyman manual should be about 3000 fps to 3100 fps. Nosler manual has it at 3200 fps. Need chronagraph to know for sure. hope this helps
