guess my old post fell off.
http://www.karrisguns.com/catalog/product/4261b46f8ade457280eb8952df9cb894

I bought one of these uppers with the pistol kit they sell. melonited upper and bcg.
I had reported a few meh issues. Some scuffing right out of the box, detent pins that were very sticky till I cycled them a bunch. Then I didn't need tools to take it apart.

I finally got out to the range with it.
First round was kind of sticky chambering. it wouldn't fully seat.
couldn't tell you why as it stopped doing that after the first round.

I only ran 60 rds or so, as I was trying out other guns. but they all ran perfectly.
using a red dot I was grouping pretty good at 50 yards.
Didn't try any bench rest shooting or anything closer.

I would recommend and would buy again from them.
BUT, if you are one of those people that your new stuff must be perfect, I would see if anyone else had finish issues when they got it new.

if function is all that maters for the price, then this is a good buy.

thanks for the info, i checked the sight out.