This BCG will ruin your gun
Nitride Boron coating turns working surfaces into a friction fit with extreme scoring of components. This BCG is out of tolerance and will reduce the pressure enough that the bolt will not lock open on a single round fire. Brownell techs know about this problem yet continue to recommend a functional replacement.
Do not buy
The reason youre buying this is for the NIB coating and it flat out just sucks. Theres burns on it that do not come off. This is not a true NIB coating like one youd get from fail zero. I have yet to experience any mechanical issues with it, but if you want an NIB coated carrier, look elsewhere.
DO NOT BUY!
Not a good aftermarket BCG!! Use masdefense instead, for about the same price its heavier, slicker, and works WAY better. This thing messed my gun up just by installing it and racking it, got scratches and didn't pull as good as the original. My buddy showed me his nickel boron bcg from masdefense(not promoting them, sure there are other good ones available), but it was night and day different. Returning asap and reading the reviews more thoroughly from now on. Already ordered a different one.
Failed after 2 rounds.
This BCG broke after two rounds. The extractor seized and I had a bear of a time getting it out without damaging the rest of my upper receiver. I also noticed that the bottom of the BCG also had some pretty good wear to the coating. This is pretty sad after only TWO rounds. 0/10 would not recommend. 10/10 will give you A.I.D.S. Love Brownells, but not this product!
Thin Coating; possibly out of spec.
Purchased this to replicate the bolt carrier of the XM16E1. This bolt carrier seemed to be a good match to the finish and look of the original carriers. However the finish is extremely thin and doesn't clean easily. After taking this rifle to the range and firing only 100 rounds of good brass ammo; the bolt became very stiff to pull back with the charging handle. After disassembling it; there was an extreme buildup of carbon within the carrier body. The carrier was also stained by Carbon and has bad rubbing marks on the side of it--which makes me think it's slightly out of spec. The carrier has since been replaced.
You Get What You Pay For
First off let me say I bought this item on sale and with a coupon bring the price that of a budget nitride BCG so I wasnt expecting too much. After the first 100 rounds it developed a black stain to it as you can see in the pictures. After the next 400 rounds I noticed the charging handle was hard to pull back, the bolt wasnt unlocking very easily. I pulled the BCG out to clean it up thinking that would fix it (it did) however I noticed the left lower carrier rail was very jagged and sharp. This is not OK as the sharp and harder steel will chew away at the softer aluminum upper receiver. For what I thought was an OK BCG for a failure like this after 500 rounds of factory ammo is not OK.
