Ruger Bisley Blackhawk .45 Colt 7 1/2" bbl

Critical Dimensions:
Clyinders after honing out.  Start at S to the left of #1 and go clockwise.
o #1 = .4524
o #2 = .4522
o #3 = .4524
o #4 = .4524
o #5 = .4523
o #6 = .4526
o full bore = .4518 (best I could measure)

I asked about some leading I was seeing in the bore and some lead on the gas
check of my 280WFN bullets on  They suggested sizing closer to
the .4518 bore.  I lubed down to .4525 than ran them through again with no lube
to get to .452.  I also dropped the charge a grain to 9.8gr Unique.  The result
was very little recoil, no leading after 50 shots, and the 1 3/8" group below:
The bullet on the right shows lead on the check from a .4525 bullet w/10.8gr
Unique.  The bullet on the left is sized .452 with 9.8gr Unique.  The one on the
left shows much less lead on the check.  That means that the check is scrapping
out less lead from the previous shot than the one on the left per the guys at

Only able to get bullets sized to .4525 without getting lube in the crimp groove.
All of the groups below are .4525 sized bullets.
280gr LBT WFN GC W-W. 10.8gr Unique. 1050fps. 1.9" group. 25 yards bench.

262gr Keith W-W. 9.8gr Unique. 950fps. 25 yards bench.

262gr Keith W-W. 9.8gr Unique. 950fps. 18 yards leaning on a tree.