I made a rough measurement of the full choke on my model 42.
I took a piece of dry soap and pressed it into the barrel and then pushed it out with a cleaning rod. I measured that and came up with .387 or a constriction of .023. I know its a rough estimate but could it be close to right? maybe .020?

Last edited by sxsman1; 09/06/11 09:10 AM.