Recently I started an AR15 pistol build, I decided to take a short cut with the lower I'd use, and went with an "Aero Precision AR-15 Lower" they usually go for around $80 bucks. The things I didnt like about the lower, was the metal was very very soft. Not soft where I could bend it with my hands, but soft as applying light pressure with pliers to install my bolt catch roll pin. The lower when attempting to install this roll pin scratched and scuffed severely. I applied electrical tape to the end of the pliers to avoid scuffing.
Pic below to demonstrate install
Another problem I ran into was trying to install my lower parts kit. I went Stag Arms lpk (lower parts kit) from bravocompany. The lower as a whole (I felt) was incorrectly machined. It seemed like every hole was way too tight for the parts. Example I had to strike the front pivot pin with a ball peen hammer a few times to smooth out the receiver hole. Than flip over the receiver and strike it with a punch. Repeated a few times, still too snug, for a fast take down. Now I know that the take down pins are supposed to be a little snug, but this was ridiculous. Their other issues I ran into, but Im too lazy to continue.
Maybe it was the lower parts kit,.... kinda doubt it. I was going to rip apart my RRA assembled lower, and try the parts in the Aero, havent gotten to that yet.
Maybe the receiver was a lemon, again it was only $80 bucks from my dealer. I've heard great things about their lowers, this just isnt one of them. Next time Im going to play it safe and go with a RRA for $150.