I thought I'd start this thread as a place to talk about shooting cast in the large bore ARs. I'm still in the early stages of cast boolit work ups for my .450 bushmaster, and I haven't hit the magic load so far. My 300 grainers are grouping about 3" to 4" @ 1,950 fps. I tried ten 230 grain BD acps at about 1,500 fps on Saturday, and I got about the same group at 100 yards that I get with a 1911 , maybe a little better, but not much. i also tried some Lyman 457193s sized down to .452 at about 1,000 fps over Unique. they shot way low, but stayed in 3 1/2".
Good news is no leading. A little plating on top of the carbon at the rear of the bolt, but no real crud in the gas system, and easy clean up.
Anybody else having luck? What have you tried? What are you sizing to?
There's a forum started just for the .450 B at:
http://450bushmaster.net/
It's more of a general discussion forum, not specifically cast boolit related. However there are a couple of guys interested in using boolits.
BD