45B20 & jamie5070-

Thanks for the interesting and useful info on M1917 barrel specs. I've been using my CMPicon muzzle wear gauge and an Ara-Mor throat erosion gage (it comes with spacers for 30-06 bolt, m1 30-06 and m1/m1a .308). Its scale goes up to 9 with the next mark being "reject". I had no idea that how a barrel was rifled would affect the reading on a muzzle gage. I have two essentially new pre 1940 SA barrels, one a star gaged 3-38 on a NM 03A1 and the other a SA 1930 that I had put on a 1.4 mil CMP receiver in a Keystone C stock. They both have TE less than .5 and MW of 0. Given my lack of patience and technical skills, I am happy to accept your experience and expertise.