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The Best AR-15 Bolt Carrier Groups: What They Really Cost

There are two faculties of thought when selecting the most effective AR-15 bolt service group on your rifle. The first faculty says the bolt is the only factor between your face and a small explosion, so it ought to be top quality.

The second faculty of although takes a more…  relaxed view of things.

The second faculty says they’re just about all the same so get whatever is least expensive and it’ll work simply high quality.  And it’s true most of the time.

But typically…

Personally, I feel the second faculty of thought is just plain silly because for a couple of dollars extra ($10-$20) you will get a VERY top quality BCG.

I solely have one body and I plan on protecting it for a long time.

(NOTE: This article is a part of my “Best in Class” collection where I record the highest decisions for numerous elements of your AR-15.  You will discover the opposite elements here: Best in Class Articles.)

Necessities for the Best AR-15 Bolt Carrier Group

(You possibly can skip this section in case you just need a suggestion and don’t care concerning the nitty-gritty tech stuff.)

I devoted a piece of my AR-15 construct guide article to the necessities for an excellent bolt service group. However I’ll repeat them here to save lots of you a click and a few scrolling.

The most essential elements are the kind of metal and the heat remedy.  Carpenter 158 steel and 9310 steel are the perfect decisions and are thankfully the most typical.  For some time, some individuals have been making bolts out of 8620 metal which is NOT acceptable.  8620 steel is far weaker and you may break your bolt with exhausting use.

When you shouldn’t make the bolt from 8620 metal, It’s the right metal for the service.  Actually, 8620 is mil-spec for the service and has labored completely for over 50 years.

It’s also essential to ensure the bolt service has a shrouded firing pin.

Shrouded vs Unshrouded AR-15 Firing Pin In case you take a look at the picture, you’ll discover which you can see the firing pin on one service, but not on the opposite.  The left hand carriers have shrouded firing pins.

A shrouded firing pin is VERY essential because without it, all of the pressure used to cock the hammer is applied to the firing pin.

An unshrouded firing pin causes extreme put on on both the firing pin and hammer and may easily break your firing pin with arduous use.  Against this, a shrouded firing pin permits the service to take the pressure and apply it extra evenly to the hammer.

All “Full Auto” or “M16” bolt carriers could have a shrouded firing pins.

To get the most effective bolt potential, there are different things to search for.  (these solely apply to the bolt, not the service) You need a bolt that’s MPI and shot peened.  MPI stands for “Magnetic Particle Inspected” and is a top quality control measure that ensures you’re getting a high quality bolt.

Shot peening will ensure:

“the finished part will resist fatigue failures, corrosion fatigue and cracking, and galling and erosion from cavitation.”

For non-engineers, meaning it is going to maintain it’s power over time.

(NOTE: One other widespread quality management measure is “HPT”.  HTP stands for “High Pressure Tested” and refers to firing a method over-pressure proof load to make sure the bolt is robust sufficient.  Back within the 60s, this was essential.  Immediately, trendy manufacturing methods have rendered it almost obsolete/unnecessary.  It’s not dangerous, however capturing a WAY over-pressure load doesn’t like the easiest way to maximize bolt life…)

Now lets take a look at some great BCGs.

FYI: When you buy after clicking a lot of the product hyperlinks on this web page, I’ll make a couple of pennies out of each dollar you spend.  It’s not a lot, however it keeps the web site going and I might respect your help. ?

Brownells M16 BCG

Brownells B-Tac BCG NitrideOnce in a while, you discover a fantastic product at an unimaginable worth and that’s the case right here.  The Brownells m16 BCG is palms down the most effective AR-15 bolt service group (for the money) I’ve ever seen.

(To be clear, I’m not saying this is the most effective BCG that anyone makes and it beats all others in high quality.  However it has every part carried out proper for a worth that’s virtually unbeatable.)

They acquired it proper with this one:

  • Each Bolt is Magnetic Particle Inspected (MPI)
  • The Bolt is machined from 9310 steel
  • Following machining, the Bolt is warmth treated and shot peened
  • M16 Bolt Carrier is machined from 8620 metal and hardened
  • M16 Bolt Carrier will perform in semi-auto or full-auto AR-15/M16
  • The Fuel Key Screws are properly torqued and staked

It checks every single field and is lower than $100. ?

Even higher, they upgraded the finish from mil-spec.

The mil-spec end for the bolt and bolt service known as “parkerizing“.  Parkerizing is pretty corrosion resistant however can also be extremely porous.  The floor isn’t clean, however is filled with tiny (microscopic) holes just like the floor of a sponge.  These pores take in and maintain oil very properly, which accounts for a lot of the corrosion resistance.


The porous surface can also be comparatively rough.  That results in elevated friction and warmth throughout operation.  Also, these pores love to get clogged with filth and carbon.  Because of that, it’s more durable to wash a parkerized floor than many other floor remedies.

As an alternative of the mil-spec parkerizing, they gave this BCG a nitride finish.

Both Melonite and Tenifer are names for nitride remedy and each are extensively used in industrial purposes and on gun elements, especially pistol slides.  (Glock uses the Tenifer and S&W makes use of Melonite on the M&P collection.)  If you’d like some extra info, I discovered a Youtube video to provide you a greater concept.

The brief version: it’s one of many two greatest BCG finishes out there.

Nitride treated steel could be very clean, very arduous, and very immune to corrosion.  The smoothness is a superb thing because it reduces friction, which reduces warmth too.  Also, nothing sticks to it very nicely which means it’s much simpler to wash.  Plus, it’s a remedy not a plating/coating so it could actually’t chip, crack or peel.

All things thought-about, that is in all probability the most effective AR-15 bolt service group for the money.

And if it doesn’t float your boat for some purpose, simply reap the benefits of the Brownells “100% forever” guarantee.

In the event you aren’t utterly, 100% glad with any purchase you obtain from Brownells, for any purpose, at any time, return it for a full refund or trade. No problem, no drawback. And, we gained’t lavatory you down in countless paperwork. Your complete satisfaction with each product we promote is what’s most necessary to us.

With a guaranty like that, how might you go incorrect?

BCM (Bravo Firm Manufacturing) M16 BCG – $169

Bravo Company AR-15 BCGIf you would like a fight proven BCG, look no further than the BCM M16 Bolt Carrier Group.  BCM has acquired a well-deserved popularity for making very top quality elements.

Actually, BCM’s about page says:

Bravo Firm USA, Inc.’s Earlier Clients Embrace:

HQ SOCOM (Special Operations Command), US Army, US Navy, US Air Drive, US Marines, US Coast Guard, numerous Special Operations Models, Division of Homeland Security, US Border Patrol, American Embassies, Personal Security Corporations, Regulation Enforcement Businesses and Tactical Models, and responsible civilians.

For sure, they get the small print right.

You possibly can take a look at any assessment anyplace, and also you’ll discover plenty of people who find themselves so pleased they gained’t purchase anything.  That – plus the fact that our army and even particular forces have used their products – ought to inform you one thing.

In truth, BCM takes high quality control so significantly that they hearth ever BCG before they ship it out.  (So it may need marks and/or be dirty if you get it.)  Objectively talking, I can’t level to something that says the BCM is any better than the Brownells… aside from the identify.

However the identify counts.

BCM has an amazing status for a purpose.

Many people have tried it, (torture) tested it, and it’s absolutely prime shelf.  It simply plain works it doesn’t matter what.  So when you kick down doors for a dwelling, I’d take a tough take a look at them.  If not, I’d save virtually $70 bucks and get the Brownells BCG

At this level, I run into a problem

In my Best in Class collection, I often listing a few half dozen products at totally different worth/quality ranges to provide you options.


You gained’t achieve much from a costlier bolt service group.  The solely approach up from here (and never everyone agrees it’s going up) is a Nickel Boron plated BCG. (and probably Nickel Teflon, however the jury’s still out on that.)  Nevertheless, Nickel Boron is tough to coat correctly and just a few corporations do it right.  These corporations cost at the least $150, and often more like $180 – $200.

Aspect observe: in case you see a Nickel Boron BCG for underneath $150 – and particularly beneath $100 – I might keep away.  The odds of them doing the plating appropriately are very low.  Low cost Nickel Boron plating can crack, chip or peel and cause perform points.

Both Nitride and Nickel Boron are a lot simpler to wash than the standard parkerized finish.  For Nickel Boron, I typicall use a paper towel and (perhaps) slightly CLP to get one clean.  Nitride could be very straightforward to wash too.  Each are mild years ahead of the normal parkerized finish.

Some say Nickel Boron plating – when correctly applied – is best than Nitride.  I’m not convinced it’s higher, and it’s undoubtedly not twice nearly as good.  (Not even shut.)  So is it value virtually doubling the price?

Generally I might say no.

There are other coatings available on the market, however most of them just don’t have the longevity of Nitride and Nickel Boron.

  • Chrome plating.  Good, but chrome is quite a bit stickier than most people assume.  My grandfather was a Hydraulic engineer at Caterpillar for decades, so he knows a factor or two about it. (they chrome plate the pistons).  Lengthy story brief, Nitride is a greater strategy to go.  It causes much less friction, can’t crack, chip or peel, and is often cheaper too. (NOTE: the within of the BCG’s fuel secret is virtually all the time chrome plated per mil-spec)
  • TiN (Titanium Nitride).  Not a sensible choice.  The commonest use you’re in all probability accustomed to is coating drills bits.  Whereas the gold colour is fairly cool, the coating could be very thin and vulnerable to sporting off shortly.
  • IonBond and other PVD (Bodily Vapor Deposition) Coatings.  They apply carbon to a surface in a fashion that makes its’ construction resemble a diamond.  Diamond is one in every of hardest, strongest and slickest materials we all know of, so the idea sounds good.  I purchased a PVD coated BCG to test.  Nevertheless, I acquired a warranty alternative after lower than 200 rounds as a result of the finish was coming off.  I haven’t tested the brand new one but.  I might personally avoid PVD coatings at this point.
  • Nickel Teflon (NP3).  I still haven’t made up my thoughts about this one.  Nickel Teflon is extra slick than most platings, however it’s additionally a lot softer.  I have a Nickel Teflon coated buffer on my AR-15 and it has a number of small dings from the buffer retaining pin.  I’ve heard it wears properly on a BCG, but I don’t have enough evidence to say Yea or Nay right now.  They will run you virtually $200.

That covers advanced BCG platings/coatings.

WMD Guns M16 NiB-X Bolt Carrier Group – $189

WMD Guns Nickel Boron AR-15 Bolt Carrier GroupIf you want to get a Nickel Boron Bolt Carrier Group, the one firm I’m positive plates them appropriately is WMD Guns. That stated, should you purchase from any of the tier one makers, you must get one thing good.

WMD Guns has their own proprietary model they call “NiB-X”. Their NiB-X plated M16 BCG is the one I recommend if you need a Nickel Boron BCG.

Yet one more thing:

It doesn’t matter what the advertising says, please don’t EVER run your AR-15 dry (no oil) it doesn’t matter what coating/plating you will have.

There is a VERY giant hole between what “can” be carried out, and what “should” be finished.

Can you run Nickel Boron BCG with out oil and be dependable?  Yes.  Nevertheless, it is best to never run any BCG with out lube.  Even when the BCG doesn’t endure, the higher receiver ought to undoubtedly have oil regardless of the BCG.


For the vast majority of us, the Brownells BCG for underneath $100 might be the only option.  It’ll work nicely as the guts of your AR-15 without draining your wallet.  In case you ever have a problem, Brownells has their 100% perpetually guarantee to deal with you.

In the event you’re an LEO or army, the BCM provides you a variety of confidence in your gear.

And that’s about all I’ve to say.

The greatest AR-15 bolt service group for you won’t be one of the best for me. So decide the one that matches your wants and completely satisfied capturing. ?