I have a ruger ssbh in 45colt. Its been pretty accurate with a bit of leading in the first 1.5" of bbl. the cyl throats were a tight 0.4505" as measured with pin gages. After opening them to 0.452", accuracy was almost twice as good, easily doing sub 2" @ 25yds offhand. Leading is pretty much gone. This is pushing a pretty soft 280gr lswc @ 1100fps. Yes size matters.

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