ABOUT COLT 6721 UPPER FOR SALE

I will attempt to look for some. The piston rings look like the bolt rings but at smaller. The outer diameter is about .375 of the inch as well as interior diameter about .310 of an inch.Very well, there is 2 variants with the 6940P, along with the 1 I'd, I am %ninety nine confident the rings within the piston were being just like the rings around