Guns, Dogs and Blades QnA

US Military disposed of its surplus in a number of its ways. IIRC there were around 4.5 million made, or maybe its 4.5 mil through the end of WW2 production.
After WW2 a lot of arms were destroyed rather than brought back. But as these remained the main service rifles until the M14, a lot were brought back, rebuilt and put in storage. Springfield, H&R, and IHC made new rifles in the 1950s.
They showed up on the US civilian market largely through the DCM until 1996 when the program was shut down. It was replaced by the non-governmental CMP which currently has two 'grades' for sale. The cheaper grades probably are best considered gunsmith specials, ie they probably need work.

I haven't looked into it, but there probably are also a significant number that were sold by armories of other nations to importers.