I purchased an unknown bolt carrier from a member on another board. IT HAS FLAWS. PLEASE READ bolded print below. It is the e-mail outlining what the seller THOUGHT was wrong with this. I have done no work on this to verify if those are indeed the actual problem, this is being sold as-is, no guarantees. DOES NOT INCLUDE BOLT [span style='font-weight: bold;']This carrier will not function without re-torquing the gas key, and staking. I bought a BCM carrier to replace this one, as my AR short stroked badly with this one. I have stripped all parts, and will be using them for repair parts, if field repair is needed...so this is only a carrier, and gas key. I have already tested the bolt off this carrier, with my BCM, and it is flawless...so I do know the issue is the gas key, I just neither have the tools, or experience to fix it. [/span] The "gunk" you see in it, is lithium grease, which can be removed with any degreaser. It was put on there for storage. THIS IS A PURCHASE AT YOUR OWN RISK, AS IS, NO GUARANTEES. Just want to make that clear. I am asking a "high" cash price, because I would rather trade for ammo, so: $85 dollars or trade for: 150 rounds of plinker (brass cased only) 9mm or 150 rounds of plinker (preferably brass cased surplus, 7.62x39) or 2 Glock 19 magazines You pay for shipping to me, I will pay for shipping to you. please contact me via e-mail, you will get the quickest response.