Anyone ever use a nickel boron bolt carrier group?
- Thread starter Pistolero
- Start date
Ian
Notorious member
With one exception (custom carrier) it's all I use because almost all I shoot in my ARs of various calibers is cast bullets, and it's a dang sight easier to clean. Also, I think it aids reliability when things are dirty. I haven't been able to hurt the coating yet, though it does turn a dingy bronze sort of color after you run it a while. Some say you don't have to lube it, but I keep mine swimming in synthetic oil and powder filth inside and out like we do on our 1911 slide rails.
One thing you need to watch out for if it matters to you is the quality of steel and guarantee of metallurgical analysis of the components you buy if they're coated. A lot of the cheaper parts are coated and the marketing hype of the coating itself seems to be more important than what lies underneath.
Marlin failed miserably at making their NiBo coating stick to their bolts, if you've experienced this don't fault the coating itself, it's VERY durable. Slamming around for thousands of rounds inside a machined tube that's type III hardcoat anodized and not getting scratched is a testament to that.
One thing you need to watch out for if it matters to you is the quality of steel and guarantee of metallurgical analysis of the components you buy if they're coated. A lot of the cheaper parts are coated and the marketing hype of the coating itself seems to be more important than what lies underneath.
Marlin failed miserably at making their NiBo coating stick to their bolts, if you've experienced this don't fault the coating itself, it's VERY durable. Slamming around for thousands of rounds inside a machined tube that's type III hardcoat anodized and not getting scratched is a testament to that.
I have (2) NiBo BCGs, one black phosphate, and one melonite (I suspect). The latter (2) were in factory built carbines, and the (2) NiBo in uppers that I assembled. Yes, NiBo very easy to clean, but then again, so is the melonite which is less $$. Spending a few extra $$ more than phosphate is worthwhile, IMO.
Ian
Notorious member
Just as a follow-up, I did get on one of the AIM bcgs a few weeks ago and have been shooting it in my newest 300 blackout build. I sprung for an Aero Precision upper (which I've found to have a lot better bore than many others) and I'm quite happy with the setup. A JP tuned and polished spring and a honed-smooth buffer tube make this one slick action.
Ian
Notorious member
I don't know if rough/irregular carbine buffer tube bores are the norm or a feature of today's "house brand" parts. All of my buffer tubes outside of my Colt are mil-spec diameter AR-Stoner from Midway USA, usually purchased on sale as a kit with spring, M2 buffer, and the hardware for a whole $34.99. What I've found to be common to them is a crushing of the threaded area inside, and some very rough radial marks throughout the inside of the the tube, but worse just behind the threaded area. A few minutes with some sort of light spray oil or ATF and a common(?) automotive brake cylinder hone turned with a cordless drill will take off the high spots and polish the rest out nicely. The goal isn't to remove all of the hard anodized coating, but to level it off on a microscopic level and remove enough of the big high spots to true the bore. Most AR's make a sickening "SCRITCRITCHCHCHREIKSWITCHITCHICHWWWWWoioioioioioing" when the bolt is cycled, and I simply cannot stand the noise or the vibration transmitted through the charging handle. I also very lightly burnish the finish on the inside of new upper receivers using the pilot of my receiver face lapping tool to smooth the finish a bit. The result of that and a light polish and radius of the hammer face is a full two pounds reduction in force required to lock back the bolt, something of high value when attempting to make a reliable, subsonic 300 Blackout with a carbine-length gas system.
After the polish, I brush Mobil 1 red #2 Li grease inside the tube and all over the spring to further soak up vibration and smooth the action. The Ni/Bo BCG is merely icing on the cake for me. Also, if you shoot cast through your AR, you will come to really appreciate the slick, non-porous coating for its resistance to lube/powder/lead fouling adhesion.
I'm seriously considering purchasing some of the brush-on moly coating that one of our more recent members has mentioned and trying it out on some tubes and uppers. A perusal of some military specifications reveal that the M-16 is supposed to have a dry moly lube coating applied to certain parts, including the entire inside of the upper receiver. I wonder why only certain boutique upper receivers from premium manufacturers offer this sort of thing? It should be standard for all those other brands who so ubiquitously hawk their products today as "mil-spec". I suppose the mall ninjas who are the primary consumers of these parts haven't bothered to educate themselves enough on the matter to keep these manufacturers honest, or at least ask the question of exactly which military specification, such as MIL-L-8937D, that the uppers meet besides the heat treatment and anodized finish type.
After the polish, I brush Mobil 1 red #2 Li grease inside the tube and all over the spring to further soak up vibration and smooth the action. The Ni/Bo BCG is merely icing on the cake for me. Also, if you shoot cast through your AR, you will come to really appreciate the slick, non-porous coating for its resistance to lube/powder/lead fouling adhesion.
I'm seriously considering purchasing some of the brush-on moly coating that one of our more recent members has mentioned and trying it out on some tubes and uppers. A perusal of some military specifications reveal that the M-16 is supposed to have a dry moly lube coating applied to certain parts, including the entire inside of the upper receiver. I wonder why only certain boutique upper receivers from premium manufacturers offer this sort of thing? It should be standard for all those other brands who so ubiquitously hawk their products today as "mil-spec". I suppose the mall ninjas who are the primary consumers of these parts haven't bothered to educate themselves enough on the matter to keep these manufacturers honest, or at least ask the question of exactly which military specification, such as MIL-L-8937D, that the uppers meet besides the heat treatment and anodized finish type.
Ian
Notorious member
Not a dingleberry hone, Bill (I was composing while you posted last), those will polish all right but you need the straight stones of an adjustable-tension tri-hone in order to take off the ridges. My buffer tubes came to me looking like the inside of a steel culvert pipe and the coils of the buffer spring literally pop and hop across the 1/8" to 1/4"-wide ridges present throughout and just behind the threaded area. It seemed intuitive to remove these ridges (unfortunately some of the coating must be sacrificed to remove enough metal to make any real improvement) and a brake cylinder hone was the logical tool since I have one or five of them and a Sucrets tin full of extra stones. The process cost JP Enterprises a $150 sale. Well, sort of. I did buy a few of their excellent $18 tuned/polished buffer springs which provide an extra bit of closing force.
Last edited:
Pistolero
Well-Known Member
Hmmm. I never have actually looked inside of the tubes! I'll give it a check when I get back
home. I ordered another nickel boron BCG from Aim. The first one I tried was really smooth and
slick, and they are MPI, meet mil specs.
I do get weird and pretty loud 'sproiiinggggggg' when I shoot, which is extremely loud when shooting
.300 BLK suppressed subsonic loads.
Bill
home. I ordered another nickel boron BCG from Aim. The first one I tried was really smooth and
slick, and they are MPI, meet mil specs.
I do get weird and pretty loud 'sproiiinggggggg' when I shoot, which is extremely loud when shooting
.300 BLK suppressed subsonic loads.
Bill