After fire-forming 100 Federal factory rounds I gave the bore a good cleaning. I removed a ton of carbon fouling but there was very little copper coming out the barrel. This is a 1953 gun with 4-groove rifling and it appears to be quite good.

I loaded 5 rounds each of BL-(C)2 at 37 to 39 grains in .5gn increments under a Hornady 150gn RN Interlock bullet with a Fed GM210M primer. This is the first five rounds out of the clean barel with 37gn of powder and measures 1.402" center to center:
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The rest of the groups were about double that size so I loaded up another 25 rounds at 37gn for testing and probably a little hunting. I need to order a Wolf reduced power hammer spring because at 6-7# I go through at least two breathing cycles to break the trigger and it is starting to really irritate me. Half the time I end up glancing down at the hammer to see if it is actually cocked even though I know it is.