[MickeyC]

Remember too that .308 cans are made for .308 bullets but 7.62x39 is actually a .311 bullet. Make sure the manufacturer doesn't make the opening too tight for the larger bullet.

 

[MickeyC]

Would you say it is adequate if you can insert a 7.62 bullet loosely in the end of the can with about the same clearance as a .308 round?

No, because bullets can cavitate before they stabilize and this often causes problems if the can is too tight. Check with the vendor.

 

[MickeyC]

Thirty caliber denotes a family of calibers, but usually refers to .308, i.e. .308 or .30-06