There are do-it-yourself Navy Chamber adapters .... I had one and it worked OK.
However, to do it right you need a .308 Win barrel swap, and a special "feeder block" to take up space between the clip and the chamber.
PS: At Barney's Wet Coast M-14 seminar a few years back, I saw a US GI M1 Garand reeciver that had been retrofitted with Chinese M-14 parts, and it worked out really nice.
[;{)
Laz 1