Posted by David Williamson on June 14, 2021, 6:01 am, in reply to "20g Field Grade"
A choke gage is good to have if you are going to buy a gun to see that it has choke/s. Using a small hole gauge and then using a micrometer is the best way to tell. In order to get the right constriction (choke) you need to know the bore. A 20 gauge bore should be .615 and your reading would indicate full/xfull.