Chuck, going through Brophy's "Plans and Specifications", I came across a print from Hunter Arms dated Feb, 19, 29 and this print is for the barrel lug. It calls for SAE 1020 and below that shows barrels saying "steel app. 40 carbon".
They also list, chrome vanadium SAE 6150 to be used for firing pins, if unavailable use Carpenter's 5317.
Chrome vanadium, I believe is drill rod and is a lot harder than barrel steel used then.
This is getting to be interesting in trying to figure out what kind of steel low graded barrels were made of.
I described this earlier in this thread about going to a scrap yard and getting some alumium round stock. I wanted to be sure it was 6160 and asked. One of the workers got a hand held machine and held it on the piece and in a few minutes read the properties of the aluminum, the fellow then told me it was 6160. I wonder if they could do the same with a barrel or receiver.
