Hi EH,

Thank you for the elaborate reply.

About your statement ;

2. It is not a throat erosion gauge and graduated for throat wear.

I know and have used both gauges MWG and TEG) for the .30 cal. barrels and .30-06 and .308 chambers ( with a change of inserts)

The .30 cal. MWG is also graduated 0 or 1 up to 3 which means that it is slightly tapered. The gauge you pictured here, is it tapered or full cylindrical??

tks,

BB