I just received my new LMT CQB MRP 10.5" upper with Noveske KX3 this last week from Wes at MSTN (awesome service, would highly recommend) to put on my newly registered LMT lower.  The upper is very tight on the lower.  After a little oil and working the rear push pin a few times, I can work said pin without tools, but I have to "squeeze" the upper and lower together as I push the pin in order to remove/replace it.  I'm not complaining, as I'd rather have an upper that was a little too tight rather than too loose; just wondering if there is any potential problem to a tight upper.  Should it loosen a little with time?  Thanks!

All I can say is take it off and put it back on a few dozen times and it will start to loosen up.

My LMT upper does the same.

My MRP is extremely tight as well. I need mechanical help (punch) to remove the pins. I am sure it will loosen up as I put more rounds through it.

Sounds perfect!

I have an LMT upper and lower that rattle to beat hell. It still shoots fine but the rattle is annoying.

I'd take tight anyday.