LRRPF52 Wrote:It was 242 (Blue) if I recall correctly.
Loctite 620 and 242 are wildly different adhesives. 620 is a high-temperature retaining compound for cylindrical slip fits. 242 is thread locker. Thread locker isn't going to do much of anything between a barrel extension and receiver. Thread locker doesn't have any structural properties that could serve a "bedding" function. 620 does, though. 620 isn't coming loose unless it's heated to 500 degrees, when used properly. It's very strong.