question on bedding the barrel extension into the upper

[Klaus Von Richter]

I use loctite to bed any AR barrel I want accuracy out of. If the extension doesn’t fit tight in the upper, you will have accuracy problems. With that said, do not use 242 or 271, also know as blue or red. They are thread lockers and not right for the application. Loctite 619,648, and 680 are retaining compounds. They are made to fill in the gap on a slip fit.

You will notice a difference in accuracy by bedding a loose fit on an upper and barrel extension.