I've had the 5" barrel since December last year. It came with blue locktite to use on the threads for the flash reducer but I have never used it because you have to take the reducer off the barrel to clean the gun or swap the barrels which I do occasionally.
When I get the 5" barrel I'm getting this one.
Blue Loctite is recommended for BOTH. Buyer beware.tandemkross: We recommend a little blue loctite for securing it tightly so that it does not loosen up with repeated firing.