Standardized Shotshell dimensions.

[Richard Flanders]

I have a Clymer 12ga rim recess reamer I got to ream out my DH12 that has issues with Win AA hulls that have out of round rims. It has no issues with Rem STS hulls or old paper hulls. I've never reamed it yet because when you slide the pilot into the chamber and put the reamer cutters against the breech it's clear that the breech is not cut orthogonal to the bore center line as the cutting teeth aren't hitting evenly. This is assuming, of course, that the reamer is properly machined, which is not guaranteed. I can't see where the breech wouldn't be orthogonal to the bore. Anyone ever see this before? My cure for the DH12 has been to never shoot AA hulls in it. My 28ga Repro sticks with AA hulls also, sometimes seriously enough that you can't get it open without gently clamping it in a rubber jawed vise just enough to allow releasing the lever and opening it. So, I don't shoot the newer AA HS hulls in that one either. Vintage paper shells have nice round rims and work just fine.