In my opinion choke gages are useless. I had a 16 gauge that I wanted to sell and the barrels were cut to 24 3/4", from the records they were originally 26". This gun still had the .650 bores and with my Skeet's gage the choke was still .014 in both barrels. A fellow was looking at it and wanted to use his choke gage and it showed full choke.
You have to know bore size before.

David