With temps. -20, I took on the indoor job of adding bolt blocks (bolt guide) to the Uberti single actions I use for SASS shooting.
I had made them for my open top cap and ball revolvers, which I shoot more often, but had put off this on the '73.
I just recently got a match for my .44-40 so I did them both.This tightens the bolt from side movement, even if you don't shoot real fast it takes a lot of the side slop in the cylinder.
I got coached on my first one by Mike and also in Jerry Kuhnhausen's book.
If your single action Colt doesn't have this addition, your missing something good.
I know this Is part of 45 Dragoon, Mike's tuning.