Gun: Ruger SRH, 454 Casull, 7.5" bbl
45 Colt loading:
W-W brass, new
CCI 300 "standard" pistol primer
8.5 grs Unique powder (2009 manufacture)
Bullet is Lyman 454190, 250gr cast, plain base, sized/lubed to .454"
I chrono'd some of these loads today, and was kind of surprised at the ES (extreme spread). This is the result of 5 rounds @ 15':
I thought the ES of 70fps was kind of high, but maybe this is normal for this round fired in the longer chamber? (454 Casull). They say this bullet is the old classic design for the Colt, so I went with it. All charges were carefully & individually weighed out one at a time on a scale, then bullets seated immediately with a light roll crimp. The powder manufacturer (Alliant) suggests 9.5grs for a 250gr lead bullet for a velocity of 941fps, but some of this will be fired in a much smaller, lighter, 45 Colt-only chambered gun (Taurus "Judge"), which doesn't have near the strength of the 454 Ruger, so I dropped down a grain to "err on the safe side". Do you think I need to bump the charge up a little to get the ES to "settle down"? Or maybe use less powder? (the case is only about half full, as it is, with this charge weight) Should I change to a "magnum" primer?
I'd consider switching to a different powder, but I have a 8 lb canister full of this and would like to use it, not just have it taking up space and gathering dust on a shelf. I have a .452" sizer die also, but have not tried that. Although the bullets were cast from regular wheelweights, I found leading to be almost non-existant. It was so windy during the testing that I made no effort to check accuracy. I have not encountered any of the problems others have sometimes mentioned about firing Colt rounds in a 454, then having problems later on chambering the longer 454 Casull round, even after some 200 or so Colt rounds fired thus far. Tips, ideas, suggestions?