I have a 24" White Oak SS Heavy Varmint barrel (.920" at muzzle) with a 1.000" diameter tenon. I want to mount it in a DPMS Lo-Pro upper receiver which has a 1.0020" diameter where the barrel tenon fits. My question is what do I use to fill the gap between the barrel tenon and the receiver? I am familiar with LocTite 638 Retaining Compound and Loctite 60 minute Extra Time Epoxy. Looking for something that will hold up with heat and would permit the barrel to be removed.