I just assembled my lower, not as bad as I thought the only parts that went flying were the bolt catch plunger and spring during a test fit.  Found them however, now that I have assembled the bolt catch, it dosen't seem like I have tension from the plunger.  

I tested it prior to final assembly and it moved.  Any advice?  With everything assembled it does lock and releases fine when pulling back on the charging handle.

Karl

Does the bolt catch roll pin fit through the hole in the bolt catch without any resistance?

The reason I ask is that the bolt catch that came in my RRA "lower receiver kit" had a molding/casting flaw in the hole that I had to remove with a dremel tool before it would rotate freely on it's pin.

No, I had to tap it in with a punch and hammer.  Everything fit the way it should with my Mega Lower.

Karl

Never mind problem solved.  I put a little Hoppe's #9 on it.  This has been soaking since my original posting and I just checked it and it's fine.

Oh, I'm sorry let me rephrase that "I played with it" ;) can't wait to try it out.