Grant:
For 12 gauge, .090<.105" customarily considered the acceptable minimum just ahead of the chambers or cones. Despite this oft repeated caveat about the location of the "minimum", I very much doubt that any reputable dealer would even consider selling a gun with the thinnest wall section located just ahead of the chamber. There is a difference between the thinnest area of the barrels and acceptable "mimimum" for a given area. Someone lengthens chambers and runs out into the quick taper of the exterior striking in the first four inches of the barrel and the location of measurements greater than "minimum" but less than the "minimum acceptable" FOR THE LOCATION become absolutely critical whatever the convention for measuring "minimums".
jack
