Longevity, Accuracy Tips for the AR15

[customcutter]

I had this discussion with Bill A. about grease on the threads, and he mentioned the benefits of cosmoline over white lithium grease, which rots and smells.

I have done some where I tried thin Remoil over my Cerakote finishes. Every receiver I mess with now is Cerakoted, so I don't have a steel on aluminum fit anyway. The Cerakote galls when dry, so it's best to have oil on the threads. Other than that, I'm not sure how big a deal it is.

Here's the picture of the M4 that appears to have the threads stripped on the upper too:

Interesting, improper heat treat, too much heat transfer due to rapid fire, possibly heated with a torch to remove stuck barrel extension from upper? If I had to guess I'd guess the later. Maybe even the barrel nut was over torqued and damaged the threads.