After 6 months with my NF pistol lower, JSE 7.5 upper and after a couple thousand rounds of steel and brass along with 1500 rounds of .22 with a CMMG conversion bolt she still going strong. I've only done 2 mods like using metal take down pins and dropping a quarter inside the buffer tube due to the back of the gas key was making contact with lower during cycling.

Trigger still feels the same and the hammer show some wear but nothing to worry about for now. I was planning to slap a metal lower on it, but I think I'll just build another pistol cause this one has'nt failed once at the range so far.

This thing is awesome on the pistol range and my prefer target is 20 spent shotgun shells hanging from string and you can really get after it with a 20 round mag, fun, fun, fun !
But she can still nail the 6 inch gong at 100 yards. I really can't complain about anything since I'm spending more money shooting ammo than the cost of the build  

Gotta say these things are a hoot to shoot !

So how did you know that the bcg was making contact with the lower?  Could you actually see the beginnings of a mark?

It was leaving a mark and I could even pull the charging handle back and see it make contact too.

My hammer looks a little more worn then yours but I have al;most the same experence with a plum crazy lower
except the hitting the tube part