FailZero EXO Coated M16 / AR-15 Bolt Carrier Group - Black

Like many that have had issues with this part failing to cycle. I learned that it’s the GAS KEY isn’t crimped properly and fails to cycle after a few shots. It took some head scratching and proper inspection to find the issue and properly torque down the gas key and crimped the bolts so they would not get loose again. After that it runs as advertised

Love this bolt for function and maintenance purposes. Handles heavy use and carbon buildup very well. I have not had a mechanical failure while using the bolt even during high rounds count days.

This bolt functions like it’s on rails quiet and flawless. It fits the Aero products with captured recoil buffer and spring perfectly and adds to its quiet reciprocation. I would call it the operators choice for lack of silver reflectivity but keeping flawless functionality!!!

There are so many to choose from and it can come down to reviews to help make a choice. I will clean up extractors, polish bolt faces, and polish barrel extensions as part of a build. This bolt needed none of that and the finish allowed carbon to be wiped off with a paper towel soaked in BoreTech. I'd prefer a Young Manufacturing NM carrier, but they are hard to find and have gotten to be $$$.

I purchased this from Failzero a few months back and like the title says I put 300 rounds through this in my Franken rifle and I’ve had no problems. I like the nickel boron finish, I like the black teflon(at least I think it was teflon?) coating that some people have a problem with because it does wear in certain spots. My criticism of the bolt carrier group is that it doesn’t have as aggressive staking as I would like. I talked to one of the representatives from failzero about the staking and they said if we steaked it any more than they do the disruption in the metal tends to crack and flack the nickel boron exo finish. My suggestion to combat this is maybe don’t have the gas key coated in the nickel boron and coat it with something else. I’ve seen videos on YouTube where failedzero nickel boron bolt carrier groups gas keys have had problems because the screws get loose and it fails to seal. Though mine has not had this problem yet.

Very easy to clean, carbon wipes of easy.

The coating on this bcg is really nice. I was really excited to see how it performed, but after 3 rounds it was obvious that the gas key was leaking. The leak was so substantial that the bolt could not travel far enough to load the next round. On further inspection I could tell that the front Allen screw was damaged during manufacturing. I tried 2 other bcgs and they functioned perfectly. I give it a three star rating because the coating and staking are exceptional, but this should not have made it past QC.

Machining of BCG is good, but the black coating easily comes off on any exposed/defective areas. Mine has multiple defective spots within the coating and these spots with gentle rubbing/cleaning easily removed the black coating. Also read the note that states the black coating will come off at the contact areas. I.e. create exposed/defective areas that will continue to chip and erode thru normal cleaning.

Purchased Fail Zero after pin on extractor from a PSA bolt broke and caused malfunctions after 200 rounds. The Fail Zero BCG functions, it's reliable and has far exceeded the BCG it replaced. No malfunctions. No failures. It cycles perfectly.

Great bcg. Operates flawlessly and looks amazing!!