Re: Just for my hero Kirby
OK, a couple answers, kinda
I have one of kirbys 7mm AM's, It runs 200's at 3250-3300 fps, its a 9 twist 30" lilja and shoots them quite well from the limited testing I did the first year after I got the rifle.
Now about the cases, the 7mm AM isn't a shortrened 338 LM, just necked down and imprroved.
its much better, stronger brass than you can get in the RUM.
you can form them yourself, or kirby can form them for you.
Why are you wanting to use the 200 WC's for muley's to 900 yards? though they are great bullets, where they excel is on elk and deer beyond 1K.
Personaly I shoot accubonds, 160's and have taken whitetails with them to 1350 yards, though my load is running out of steam fast at that range it still retains just under 1000 ft/lbs of energy at that range. I'm needing a new load and thinking about the 180 bergers but due to my daughters medical condition I've put most of my projects on hold until the funds allow it.
So I'll be loaded with the accubonds again this fall and plan on taking the 20th deer with this rifle the first day or so of the 4rth season since it was built.
the headstamp may say 338LM, but I firmly believe that if you get kirby to build you a 7mmAM, you'll be extremely pleased with the results you get. My 7mm AM is the most accurate, least temperamental rifle I've ever dealt with, it shoots anything very well. Hope this helps answer your ?'s.
Born to Hunt, Forced to Work!