Having a minor issue with leading in my guide gun, and I just want to make sure I'm on track here.
Details as follows...
Boolit: Accurate 46-360M sized to .460 (.4585 groove diameter)
Alloy: Roto Metals Hardball aircooled
Lube: White Label 45/45/10
Powder: Accurate 5744
I started at 31.5, and worked my way up to 33.5grs. 31.5 delivered an average velocity of 1474fps, with 33.5 delivering an average velo of 1558FPS. Roughly a 20-30fps increase per every 5/10ths of a grain of powder. 31.5gr delivered exceptional accuracy, but the faster the boolits went the worse accuracy got finishing up with a 3" group at 50 yards.
Upon further inspection of the bore after letting solvent sit in it overnight, I am seeing lead streaks following the rifling thru out. My first thought that comes to mind is that I am not pushing this alloy hard enough. Maximum chamber pressure for this alloy should be in the 37,000psi range, and the working chamber pressure of the load should be at 27-28,000ish. It appears no obturation is happening, but here is my head scratcher.
My brain is telling me to slow these down even more. The load of 31.5grs delivered a sub 1" group for 4 shots at 50 yards, where as the faster loads yielded poor accuracy.
What should I do here? Keep playing with 5744, slow these down to 1400fps, see what happens with the bore and go from there? Abandon 5744 altogether, step up to H322, and start pushing these guys faster and see if I can achieve obturation and stop the leading?
Thanks for the help.