Thought I would measure up some dovetails on various .22 rimfires, both US made and a variety of European/Chinese models mostly made for the US market though. The variation was huge across the flats as well as in the dovetail groove itself. So much so that I'm not sure where the correct place to measure is now.If it's meant to be standard 3/8 or 11mm or whatever it appears that in dovetail groove itself is probably correct but some of the very narrow dovetail flats also fell within these ranges. Anyone help with the correct way. Thanks

Thanks tnekkcc. Thats perfect. And I thought it was just me!

3/8 dovetails are are usually measured across the flat and euro dovetails (11,13, and 19mm) are usually measured in the groove. this is specific to flat topped dovetails not dovetails cut into round receivers and left radiused.