A sports car needs a great engine. An awesome AR-15 needs a great bolt carrier group (BCG).
But there are A LOT of choices.
From full-auto to lightweight, different coatings, MPI inspections, and more. It can make you go nuts (the above is probably only a few of my BCGs).
But don’t worry, we’ve got our list of our go-to BCGs.
We’ll cover some of the choices and then our favorites for different purposes and budgets…from mil-spec to lightweight, gas-reduction, and even some builds just for looks.
THE QUICK LIST
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Best Overall BCG
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Best Nitride BCG
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Best Nickel Boron BCG
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Best Bang-for-the-Buck BCG
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Most Affordable BCG
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Best Lightweight BCG
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Great Titanium BCG
Table of Contents
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How We Tested AR-15 BCGs
There’s no way around it…the Pew Pew Tactical team shot a lot of rounds across a lot of BCGs during our testing of complete rifles, builds, barrels, optics, & ammo.
And now that we’ve been testing more silencers and NVGs, we’ve added thousands of suppressed rounds downrange that have a habit of really gunking up (and testing) BCGs.
Here are our criteria for how we chose the best BCGs:
- At least 2000 rounds across at least rifles over a 1 year timeframe
- At least 1000 rounds running 100% without lubing or cleaning
- At least 500 rounds suppressed
- Meets or exceeds Mil-Spec standards
- Individually MPI (magnetic particle inspected)
Best AR-15 Bolt Carrier Groups (BCG)
1. Bravo Company Manufacturing (BCM) M16 BCG
Prices accurate at time of writing
Prices accurate at time of writing
-
25% off all OAKLEY products - OAKLEY25
Copied! Visit Merchant
Pros
- Mil-spec everything
- Each BCG is MPI & HPT tested
- Each BCG is test-fired for function
Cons
- None
Let’s just start with our overall pick for the best mil-spec BCG.
If you ask most people online what’s their go-to BCG…the vast majority is going to be BCM’s M16 BCG.
Nothing much to say except it’s mil-spec everything and has a great reputation.
Each individual BCG is MPI (magnetic particle inspected) & HPT (high-pressure tested)…plus test-fired.
We’ve run multiple ones in 16″ builds that is up to a 3000 round count…
And more lately…a 14.5″ pinned AR and another 1000 rounds through a 11.5″ that gets dirty suppressed.
But no matter what we threw at it…the BCM BCG kept on chugging. That’s why BCM is also our go-to for AR-15 uppers.
What’s your take on the BCM? Give it a rating below.
2. Rainier Arms Match Grade Nitride BCG
Prices accurate at time of writing
Prices accurate at time of writing
-
25% off all OAKLEY products - OAKLEY25
Copied! Visit Merchant
Pros
- Nitride coated
- Individually MPI & HPT
- Extra-power extractor spring
- Looks different
Cons
- Gas key staking not as deep
Want something that’s mil-spec AND Nitride coated for easier cleaning? Check out Rainier Arms’ Nitride BCG, which meets or exceeds mil-spec.
Plus it has a different/more aggressive cut on the carrier around its logo…if that matters to you.
Each BCG is MPI and HPT plus they have an upgraded Sprinco extractor spring. We’ve heard from some that the gas key staking isn’t too deep, but ours have been fine and with zero failures.
We’ve used several units of these in our random AR-15 builds from 5.56 to .300 BLK to great effect.
3. WMD Guns Nickel Boron BCG
Prices accurate at time of writing
Prices accurate at time of writing
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25% off all OAKLEY products - OAKLEY25
Copied! Visit Merchant
Pros
- Easier to clean Nickel Boron coating
- Silver color pops out look-wise
Cons
- Darkens with use
Nickel Boron (NiB) used to go for a lot more in price but now they’ve stabilized.
I do like them in terms of increased lubricity and ease of cleanup. Plus, the silver color pops out in your upper receiver.
However, the more you shoot it (especially suppressed)…it will turn a little darker. Don’t worry, that’s totally normal.
My WMD NiB BCG has been chugging along in my AR pistol for a few thousand rounds…and I’ve only needed to wipe it down with some cleaner and microfiber cloth.
4. Toolcraft Nickel Boron BCG
Prices accurate at time of writing
Prices accurate at time of writing
-
25% off all OAKLEY products - OAKLEY25
Copied! Visit Merchant
Pros
- Easier to clean Nickel Boron coating
- Each MPI tested
- Great value
Toolcraft is another gold standard in the BCG manufacturing world.
And now they have their nickel boron model at an awesome price.
The coating is super slick when new and doesn’t get as dark as my WMD.
Plus lately we’ve been seeing it with free shipping.
5. Palmetto State Armory (PSA) BCG
Prices accurate at time of writing
Prices accurate at time of writing
-
25% off all OAKLEY products - OAKLEY25
Copied! Visit Merchant
Pros
- Mil-Spec and MPI tested
- Most affordable
- Very reliable
Cons
- Cosmetically could look better
This is where you can go stupid cheap on builds…that still work reliably (PSA AR-15 Review).
Their mil-spec phosphate BCGs are a little bumpy but they work and we’ve had thousands of rounds through them over 5+ years.
6. Walker Defense Titanium BCG
Prices accurate at time of writing
Prices accurate at time of writing
-
25% off all OAKLEY products - OAKLEY25
Copied! Visit Merchant
Pros
- 7.8 oz (33% less than regular)
- Specific materials & coatings chosen
Cons
- More expensive
Another recent addition from the makers of the most hi-tech AR-15 muzzle brake…one that’s 3D printed from Inconel (think rocket ship engines).
I’m really digging their Titanium BCG for 5.56/.300 BLK. If you look closely, you’ll see that the Titanium carrier is black DLC (diamond-like coating) while the bolt is silver (nickel-boron).
The DLC was chosen for high wear resistance and a low coefficient of friction. While the Nickel Boron on the 9310 steel bolt was chosen for being easy to clean, having a low coefficient of friction, AND with the benefit of heat dissipation.
Something something about the bolt having similarities to a heat sink and making contact with fresh/cooler air.
The main thing is that it looks great and is performing great so far in my competition rifles.
It’s $300+…but the makers have hooked you up with coupon code “PEWPEW” for 10% off.
7. Rubber City Armory (RCA) Titanium BCG
Prices accurate at time of writing
Prices accurate at time of writing
-
25% off all OAKLEY products - OAKLEY25
Copied! Visit Merchant
Pros
- 7.8 oz
- Titanium carrier
- Still looks good after lots of rounds
Cons
- Most expensive option
Another go-to for competition shooting is the RCA BCG but it costs a pretty penny since the carrier is Titanium.
I’ve shot many thousands of rounds through it, and it still looks new…not even that many wear marks on the touchpoints.
The total weight is 7.87 oz which isn’t that much less than the other steel-cut lightweights…but I like having the complete full-auto form factor.
It has a 9310 bolt, but that is the standard for lightweight builds.
8. Brownells Lightweight BCG
Prices accurate at time of writing
Prices accurate at time of writing
-
25% off all OAKLEY products - OAKLEY25
Copied! Visit Merchant
Pros
- 8.2oz weight
- Much more affordable than titanium
Cons
- Some coatings are always out
Brownells has thrown a contender into the ring with their lightweight BCGs. And now with different coatings.
I, of course, went with their Titanium Nitride (TiN).
Their bolt uses 9310 steel, but again…it is likely never going to matter and is the standard for lightweight builds.
It weighs in a little heavier than the Titanium counterparts at 8.2 ounces but is less than half the price.
9. KAK K-Spec BCG
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25% off all OAKLEY products - OAKLEY25
Copied! Visit Merchant
Pros
- Vents gas downward
- Sandcutting rails
- Dual ejector
This BCG solved my over-gassing problems on my 10.3″ MK18 once I had my suppressor installed.
Because if you don’t have an adjustable gas-block…and you’re running a standard suppressor on a short barrel…you’re going to get tons of gas in your face.
I didn’t want to take my factory MK18 apart to add an adjustable gas block…so I got the K-Spec which has some great features.
First up…some aggressive “sandcutting” rails that help divert debris into less critical areas of your AR.
And probably more important to me for my purpose…the gas diversion holes that go into the magazine.
Now hold up…did I say magazine? Yup!
It sounds weird but chances are your mag gets really dirty from any kind of suppressed shooting anyways. Check this video to see a side-by-side.
Lastly, the dual ejectors are meant for enhanced reliability. I’m close to the 2000 rounds into it but so far so good.
Much less gas to my face and a proper 3-4 o’clock ejection with zero hiccups.
10. Bootleg Adjustable Carrier
Prices accurate at time of writing
Prices accurate at time of writing
-
25% off all OAKLEY products - OAKLEY25
Copied! Visit Merchant
Pros
- Adjust gas on the BCG
- Great for short barrel suppressed builds
Cons
- More parts that can go wrong
Here’s a BCG that has a trick up its sleeve…
Bootleg’s adjustable carrier gives you this capability in the BCG itself with a couple of clicks on the side.
So far, I can definitely feel the recoil difference between the different settings.
And although there are only 4 settings, so you won’t get down to the perfect setting for your rifle and loads…
Great if you’re starting a suppressed build but don’t want to mess with an adjustable gas-block.
11. Sharps Xtreme Performance BCG
Prices accurate at time of writing
Prices accurate at time of writing
-
25% off all OAKLEY products - OAKLEY25
Copied! Visit Merchant
Pros
- Super tough BCG
- DLC coating
- Worked well with steel case ammo
Cons
- Some proprietary parts
Sharps Rifle Company has a storied history strongly tied to the Old West.
It’s pretty cool to see they are still around innovating products like their Xtreme Performance Bolt Carrier Group.
The XPB has a patented Relia-Bolt and is machined out of S7 tool steel. During its creation, each one is thermal-cycled before being treated with a diamond-like coating.
With a reputation for absorbing punishing treatment, I put this one to the test. With nothing more than an initial lube, I ran this bolt carrier suppressed at breakneck speeds for just over 2,000 rounds…the last 500 or so were steel-cased.
This is a recipe for testing a lot of parts but particularly the BCG. The Sharps passed with flying colors, and the clean-up, even though it was filthy, was a snap.
For a super tough and reliable BCG, look no further than the XPB.
Full Auto vs Semi-Auto Bolt Carrier Groups
First off, “full-auto” BCGs are legal and don’t magically make your AR-15 automatic firing.
The slightly longer and heavier bolt carrier group has an additional lug at the rear of the bolt carrier group.
On a full-auto AR-15 or M16, this rear lug pushes the sear release downwards, which allows full auto (or burst) fire. In a semi-automatic rifle, this has zero effect on how the gun functions.
Semi-auto carriers are now the ugly step-child of the BCG world and don’t have many purposes…like commercial buffer tubes and stocks.
The semi-auto ones have an extra cut that takes out some mass which should help with reliability. Semi-auto versions used to be significantly cheaper than FA versions, but now the difference isn’t as drastic.
Main lesson…get a full-auto weighted BCG if reliability is a concern.
How to Choose a Bolt Carrier Group
Mil-Spec is a bit of a buzzword in the AR community. It generally means the rifle is built to pass military specifications.
Mil-spec doesn’t mean the greatest ever or worst; it’s just in spec to a military contract. Here are some of the important bits:
- High Pressure Tested (HPT)
- Magnetic Particle Inspected (MPI)
- Heat treated and shot peened
- Bolt carrier machined 8620 steel
- Carpenter 158 steel bolt
- Chrome-lined interior bolt carrier key and bolt carrier
- Torqued and staked gas key screws
- Coated with a matte black mil-spec finish
HPT and MPI Tested
See that “high pressure tested” and “magnetic particle inspected” above? That means each bolt is individually tested at a proof load.
Usually, it’s printed onto the bolt (either as MP or MPI). But not all the time.
If it doesn’t say in the description…it probably is only batch tested. And you never know if a batch is 10 or 1000 BCGs.
Again, if it’s a duty or self-defense gun…I’d opt for something MPI and HPT tested.
Different BCG Coatings
Mil-spec means phosphate coated and is matte and a little bumpy. Which does its job but does require more cleaning than newer coatings.
New coatings come and go…and they all say they are the latest and greatest. Here’s my opinion…
- Nitride is black and shiny. And is easier to clean.
- While Nickel Boron (NiB) is silver and shiny. And easier to clean.
- And more exotic stuff like Titanium Nitride (TiN) is gold and pretty. And easier to clean.
Why Use a Lightweight or Low-Mass Bolt Carrier?
Low-mass or lightweight bolt carrier groups are relatively new on the market. We also have a whole guide just for choosing a lightweight bolt carrier group, so be sure to check that out if you want to know more.
A low-mass BCG serves two purposes.
If you are following the current fad of super lightweight AR-15s, you want to trim weight basically everywhere. You can cut a few ounces off by using a low-mass bolt carrier.
A Mil-Spec BCG is about 11.6 ounces, but you can be much lighter now…especially with cuts and exotic materials like titanium. The primary advantage of this is to reduce recoil.
Since the bolt carrier group is shot backward towards the shooter, the weight of it affects recoil. The more mass you have coming rearward, the more recoil you’ll feel.
Any reduction in recoil and firearm movement, in general, helps you stay on or get back on target as you fire. A low-mass BCG moves faster, which could increase your rate of fire, but skill ultimately makes a bigger difference in cyclic rate than bolt weight in a semi-auto gun.
Why do regular bolt carrier groups still exist?
A lightweight BCG is designed for a tuned rifle and a builder who’s willing to toss an adjustable gas block on and really tune the gun. The heavier standard BCGs are better suited to running any kind of ammo through any kind of gas system.
So, if you’re building a SHTF, zombie-apocalypse-proof, rifle…go with a regular BCG.
Building a performance-tuned competition rifle with an adjustable gas block? Go with a lightweight BCG. Here are some of our favorites…
Final Thoughts
That does it for BCGs. There are lots to choose from, but the important part is identifying your use case so you can select the right BCG for the job.
Hopefully, our list was able to help you get pointed in the right direction!
What kind of BCG do you run? There are so many BCGs out there, so let us know what we missed. Looking for more AR parts? Check out our article on the Best AR-15 Upgrades!
LATEST UPDATES
May 16, 2024 – Added How We Tested, adjusted choices based on latest testing, and added additional information for choices.
120 Leave a Reply
SOLGW is the best in terms of Warranty, Pre-Inspection and it is a Microbest just like the BCM.
Doesn't Toolcraft make a lot of name brand like BCM and Aer Precision. You forgot Leitner-Wise
How is there no mention of a single NP3 option, like Sionics?
Consumer grade "milspec" is "milspec" in dimensions only - for parts compatibility.
Consumer grade "milspec" can be manufactured from non-Mil-Spec material, such as 6061 aluminum instead of 7075 aluminum and still be called "milspec".
There's a lot of quality assurance inspections that go into actual Mil-Spec hardware that aren't performed on consumer grade "milspec" parts.
Actual Mil-Spec is not the same as consumer grade milspec.
I have used many different BCG. I do this because I store my rifles without them in it. I try to keep upper manufacturer the same when possible. I prefer nitride coatings for easy of clean up and I don't like shiny. They should also be at minimum MPI tested but prefer HPT also. One real nice Sons of Liberty Gun Works (SOLGW) upper has one of my favorite BCGs. SOLGW does not have a nitride version, only phosphate, so I went with the CMC Triggers since they don't make an upper. It's extremely well made besides having a great finish. Aero Precision and Faxon are very good, though the Faxon doesn't show HPT. At the time I was buying a 6.8SPC I couldn't find a complete BCG. I end up buying an RCA carrier to mate to a Faxon Bolt. This worked well. I changed the RCA carrier with a Battle Arms Development (BAD) one to match the upper, taking the BAD bolt and using in the RCA. Cross Machine Tool will be for next build since I liked my friends. Will pick up a Dimondback Firearms BCG to go on my beat around truck rifle. It cheap for meeting my criteria of nitride, MPI & HPT. Plus has on logo like the old phosphate mil spec in there now. Logos on others help keep who goes where.
Unfortunately, BCM is someone who I can no longer do business with. First, I ordered their stripped MK2 upper from Optics Planet and it was placed on back ordered, that was 4 years ago. I keep on back order to see if it shows up before I die out of curiosity. They obviously don't care about their retailers. Last straw was trying to order a non-FFL part directly and they told me they wouldn't sell to Mass. Now I won't order their parts from any retailer.
That’s an Optics planet problem. If something is ever out of stock around the gun world, OpticsPlanet will still try to sell it like they have it in stock, but they never do and you will wait for eternity. My experience.
Yes, part of it is an Optics Planet problem. OP should have taken it off their website a while ago. Since BCM is still making the part and not shipping to their dealers that is not on OP.
BCM obviously at some point said yes to providing OP with this upper at some point. I understand the pandemic hit and brought manufacturing to a halt. The thing is that once they started making again, they kept all to push on the BCM website. Looking to sell complete rifles for a larger profit instead of honoring their commitment to OP for just the upper.
BCM has no excuse not to sell a product to MA that is legal to own here, and every other place will.
No KAC’s Sandcutter or LMT’s enhanced BCG among the best? Oh okay, even Lantac’s enhanced BCG is much better than all above expect the Sharps Rifle one maybe.
Don't leave our LWRC's nickel boron model, it's a work of art!
My Aero Precision nitride BCGs, on AR-15 and M-5, are butter!
Ever done a best rifle mounted ballistic rangefinders?
They’re becoming so popular in the long range shooting world
MI-CRO-BEST.
(2) of my favorite BCGs among our 4 ARs are an Aero Precision nickle-boron BCG and a PSA nickle-boron BCG.
not one mention of a SOLGW, FCD, or Hodge BCG is absurd.
Like your information.
Own a Bootleg adjustable. Works best as a paperweight. Very unreliable regardless of position. I’ve tried it on multiple AR’s with the same issue. Tried to get help from Bootleg customer service and got ghosted. Not sure how they are still in business.
If you need a bcg for a can, go with the KAK
have you seen the carrier from speed-tac
Hi Eric - your articles never disappoint and are well written. I would add to your BCG list, is the Fail Zero Nickel Boron (NiB). It has worked well for me and was very reasonably priced ($110), last time I bought one.
PSA brownells and aero, what a surprise! Got a JP FMOS and bolt from some guy on the internet for $200.. score!
Love the faxon one. So light.
I AM WITH THE AMERICANS WHO POLICE AND PUNISH THE BATFE… THIS IS OUR ONLY CONCERN. THE BATFE HAVE RAN THEIR LAST UNJUST ATTACK. WE HAVE ARBITRARILY DRAFTED DOCTRINE AS WELL WHICH STATES AS FOLLOWS TO STOP THEIR FUN:
(no automatic penis or mouthfuls of jizz for BATFE)
The BATFE now needs to suckle up to a penis that they can all share like good gobblers of knob. They take take and take but this arbitrary law states “one penis per tounged mouth….. “ so one of the better thinkers decided to remove his tounge per the statue citing “one cock per tounged mouth….” then went out and stuffed a whole YMCA boys club in his mouth and see where he ended? DEAD FROM OVERDOSE OF SEMEN AND ASPIRATION OF JIZZ TO LUNG CONTACT…” Now we have again arbitrarily wrote “one penis per mouthed BATFE member per load… no penis shall be rendered to fire jizz while stand by penis is about to come under section 55.7 or 88.5 hence double loads of jizz or double or more PEENIS shall show intent on rapid fire guzzling of jizz or rapid mouth-ing off’ing of more than one (1) male penis regardless of girth, length ethnicity of male attached to or color of nor should sack containing balls or other devices be so attached nor this BATFE agent shall be considered rapid necking off of multiple penises and renders automatic mouthing off’ing of penis punishable by no less than ten (10) years maximum rectum stretching and fine no less than $250,000 (quarter million) or BATFE agent has had prior citation for choking upon or had sticky throat closure from inhalation of semen, but, juzz, jizzum, man paste or chowder OR ANY OTHER BY NAME FORM OF SPERM FROM PENIS ON ALIVE INDIVIDUAL THE PEOPLE RESERVE THE RIGHT TO MAKE QUICK CHANGES TO THIS DOCTRINE ST ANY TIME IN ORDER TO MEET OUR NARRATIVE OR BECAUSE WE HAVE WIVES AT HOME ON THEIR PERIOD VERY TUFF OR WE SIMPLY NEED TO APPEAR BUSY OR FUNDS BY WAY OF GRANT S OR DONATIONS ARE NEEDED TO FUND A COCAINE L, WEED, ALCOHOL AND PROSTITUTE PARTY THAT WE ARE THROWING OR BECAUSE WE ARE MAKING A STATEMENT TO PLEASE OUR FEMALE MISTRESSES OR ANY REASON WE WANT ETC….. THE BATFE MUST DO, SAY PLEASE WITHOUT EYE CONTACT THEN MUST BE PLACED ONTO THY POLE THICC AND LONG WITH BARE UN LUBBED RECTUM UNTIL TEARING OR BURSTING SOUND IS AUDIBLE ETC AND THESE ARE SUBJECT TO OUR INTERPRETATION AS ALWAYS NO MATTER WHAT THEY SAY HERE IN BECAUSE WE SAY SO TOO BAD NOW BE GOOD GOV WORKING INDENTURED SERVANTS WHO CRAVE PENIS, SPERM AND ANY FORM OF VIOLENT HOMOSEXUAL INTERCOURSE BECAUSE ITS JUST HOW THEY DO SINCE INCEPTION SO YEAH. GO BATFE….. ETC…. FINISH ON PAGES 3 to 987999246. All laws subject to our interpretation and are arbitrarily drafted no matter what they actually say. Ok? GOOD SO WE ARE WATCHING YOU DO NOT HAVE TO MUCH FUN OK OR WE WILL TAKE IT AWAY AND KUDNAP YOU LOCK YOU UP PERMANENTLY OR FINE YOU UNTIL PROSTITUTION PAYS YOUR BUTT OUT OR YOU FIZZLE INTO LARD. ETC…..
Can you guys remove the above post. It's ridiculous and inappropriate
Give me that Sharp's all day long. Fantastic build and cleanup is a breeze with the DLCoating. Fabulous company and pricing too.
johhny B and his boys standing on the corner sucking that corporate dick again. beta boy will always lick the biggest shaft long as they pay his fary white tennessee ass..
I don't see the merit in showing all these "distributors" who are mostly "private label" BUYERS of their BCG from a very short list of real manufacturers, when all they do is put their name on it, when they're selling the same thing. The the real differences in quality versus cost is lost if you don't know the real source of manufacturing control and stability. Plus, how many of this list are made by the same REAL manufacturer? That would be a more interesting, informative, and transparent story on BCGs.
Facts^
I just had a meeting talking about how few manufacturers there are for BCG's.
Then list them for us.
"Mil Spec"; A specification that sets the lowest quality the government will accept. It doesn't mean something is made with the best possible material or most modern fabrication methods. In the days since Stoner came up with the design advancements in metallurgy and heat treatments have been made, but changing to an *improved* material or treatment can exclude the part from military acceptance. Mil spec is a >minimum<.
I don't know who told you that but that is not it.
Mil Spec is a Specification. Does not mean its the minimum or maximum. Just a specification, Mil-spec equipment began with a need to have proper performance and repair-ability among all military equipment. Standardizing military equipment dates back centuries.
Maybe you have a better cartridge but it its not 5.56 NATO specs they will not accept it. You can't have a bunch of non spec parts and expect everything to work together properly.
Uh...No Lantac?
Lantac E-BCG. It cycles both subs and supers flawlessly in a .300 blackout pistol. Better than any "mil-spec" BCG because of its gas porting.
PSA made the list of best BCG but DD isn't on the list?
I like bcg from Daniel defense and spikes tactical.
All this NiB and no mention of the Young Manufacturing chromed M16 BCG and bolt?
Is this the Young Manufacturing that doesn't know how to stake their gas keys?
You could have just said Toolcraft, the company that actually manufactures 3/4 of the items you listed.
Shout out to Voodoo Innovations. Awesome BCG at a reasonable price.
What about AR-15’s by Geissele?
They are a top manufacturer of complete rifles, carbines and pistols in their newer Super Duty line. And for parts they make the best trigger assemblies in the business. Love my AR-15 10.5” pistol!
Anyone have any experience with Sharps Rifle Co. BCGs?
We haven't used one yet but there has been very negative feedback we've heard.
Your feedbackers are lying to you , one of the best 556 BCG on the market! The bolt and carrier made of G7 steel an M-16 BCG
I have 329 pro builds UMB..BEST BCG. SRC.. and they are reasonably priced.
yep. awesome
I’m building an ‘AR ‘ 10 , it’s the first real build that I’ve committed to . I’ve helped others and watch a lot of gun Jesus for entertainment mostly but my experience with metal fabrication really grew when I tried to ‘ make’ a machine gun in my garage in my spare time. The reason I decided to post here has to do with tolerances of different aspects and of degrees of temper and the utility of intentional variable of the former or later. So to say that it’s all mil spec is a kind of buzafication of information . In fact so to cut corners in the learning curb for would be buyers? Of a given product or application of a feature.
Is any of this sounding like a worthwhile version of the truth?
what is the major difference between a 8620 BCG and a 9310 BCG? I am trying to do some research between the two and can't really come up with a PROs and CONs. Can you provide some input? Is a 9310 steel BCG better steel than a 8620 steel BCG?
Both steels have high hardenability and are mostly used to manufacture components with a large cross-section requiring high toughness and core strength, usually on critical aircraft engine gears, or automotive applications. You, personally wont notice the difference between performance of either steel.
So the real issue is buying a BCG from a reputable company that has either sourced or manufactured a quality party you can trust.
Your Magnetic Particle Inspection image of a bolt is actually a Liquid Penetrant Inspection image.
Can anyone recommend a BCG compatible with an LMT .308? I'm sure they have some advances with their $500 BCG but mine won't be in for months. LMT says their MARS-H platform is SR-25 and the only BCG that will work in their own BCG.
Since LMT says the only BCG that works is theirs, I would go with what they say. They have made a lot of changes to BCGs as a whole and really know their stuff.
LWRC
If you haven’t tried the Black Rain BCG, you are missing out on the smoothest running BCG on the market today. Runs better than BCM (which I love), at al slightly lower price point.
which style should i get black nitride or nickel boron?
Well wondered how you left out Lantac ?
^^ same
Not so sure the absorption of the recoil energy, which is a fixed value of the design of the gas system, would equal less felt recoil just by changing to a lighter mass of the BCG without addressing all the other components, gas block, recoil spring tension, and buffer mass. Change one and you have to adjust the rest.
Man it sucks to see how much the prices have gone up since this article was posted just a few months ago. Everything is $20+ more than it was
No joke , it’s crazy right now , hard enough to even find anything in stock at that.
Ok guys I love guns and building them and customizing them but I dont know everything about everything by far and now I'm on researching BCG's. But my question is how is a Titanium one not the best choice easily? And I say this because it's alot stronger of a steel and lighter, so ad a DLC coating and I don't understand how it doesn't automatically win? Once again I'd love some feedback and comments as I'm researching! Thanks guys!
Titanium doesn't offer as much over steel in this case as one might think. The carrier itself is a very low wear part, the only part that really takes any wear is the cam path itself and that isn't enough to become a problem very often. The weight saving is great if you're trying to tune the rifle, but it does require tuning. Combine this with the fact that a titanium BCG is very expensive and it's hard to call it the "best". It's a good option, for some people, but it's not a great option for a lot of people.
Hmmm...seems you left out an industry leader who actually makes BCGs and not rebrand someone else's. You may want to look into Barnes Precision Machine next time.
On the topic of recoil, I get the idea of 'less mass moving might = less felt recoil', but what about less mass in the BCG to absorb the recoil? Heavier revolvers (e.g, stainless vs. titanium) have less felt recoil, heavier semi-auto pistols (stainless slide vs. aluminum etc.) are known for less felt recoil, so why would that not translate to the AR platform when talking about the BCG mass? Seems the lighter BCG would at least make the recoil "snapier" than with a heavier BCG?
Normally a low mass BCG is combined with an adjustable gas block, less mass means less force is needed to move it. An adjustable gas block lets you tune the gas so that less force is put into the BCG, stacked on top of less mass coming back at you and you have a reduced recoil impulse that is also not snappy!
Great info. Many thanks
Kind of seems like a commercial for Brownell‘s, Hard to trust a list without fail zero on it.
Odin works have been perfect in one of my grendels.
I have an old Colt AR15 semi-auto BCG. The bolt itself is standard Colt milspec. I have several spare bolts and don't need an extra. I'd like to purchase a quality bolt carrier without a bolt. I have yet to find a source except for some sketchy surplus sellers. Every quality source I have seen sells only complete BCGs. Any suggestions? Or am I stuck with replacing the entire BCG to get an M16 bolt carrier?
Check JP Enterprise but I'm thinking colt bcg have a proprietary cut to them??
Try contacting E2 Armory - ask for Kaylee. She’ll be able to help you out.
Call Colt firearms directly and order from them. They might will get you the part that you need.
LMT Enhanced Bolt Carrier and Bolt! Trouble is finding one.
Exactly. I kept scrolling, looking for the Lewis. Shocked it and a few others didn’t make the list when I saw of the some names that did.
The LMT BCG is the best on the market. This clown not mentioning it, and then listing 10 absolute pieces of trash is embarrassing for a “tactical” website. should ban this idiot from writing anything and only let professionals with experience and actual knowledge speak.
Bro, seriously. I'm thoroughly convinced that PPT pushes products that they are paid to push. They've lost their credibility a long time ago.
I have ADM,AAC,PSApremium,and Colt bcgs.I firmly believe that tha Colt bcg is the best of the milspec bcgs.Until I see proof of long term high round count reliability of the boutique bcgs Im sticking with Colt.Bcm and the filthy 14 have shown reliability after many thousands of rounds.
I ve had zero issues with my blackened, polished, Nib-x bcg from WMD.... smooth as glass... wipes clean with a rag...
This article was a great read if you're a newbie unfortunately this article forgot to actually mention some of the best BCG's on the market. I own a few from cryptic Coatings, Radian, and toolcraft. I can attest to the cryptic coatings as they are by far the best. They may be a little bit pricey but you get what you pay for.
Rich, I'm one of those aforementioned "newbies." The first lesson I've learned is that - apparently - a rifle is never really finished. I've doubled the price of my first AR (Ruger AR556) with optic and other upgrades. Now, I'm thinking new BCG... for no real reason.
I've been eyeing the Radian Enhanced BCG and might throw in the Raptor charging handle and ambidextrous safety while I'm at it. I've heard lots of good things about Radian and it sounds like you're a fan as well?
Young MFG BCGs if you want real precision and aerospace component process technology. Do check them out.
What brand is the full auto in the comparison that you did? Full auto semi auto comparison
I believe 9310 steel is stronger than C158. All the “high pressure” bolts like JP Enterprises are made with 9310 and state it’s stronger than C158, which is just mil-spec (the minimum standard).
There is no best bcg.Buy one with a great reputation,for me thats Colt.I have Lmt,Psa,Lwrc they all work but Colt is inspected,tested and in spec.THE MOST TESTED.
Been running LANTAC E-BCG's in all my AR's with no issues. A little expensive but my AR's run so smooth!!
This.
Lantac is very high quality, tough as hell, and highly sought after. Surprised it didn't make the list, it is far superior to Bravo.
What about Sharps Rifle Company XPB BCG.
Primary Weapons Systems DI BCG should be #1, followed by POF, BCM #3. IMO
A bcg i purchased a while back that have had zero issues with is sharps rifle co with its reliabolt. The lugs on the bolt semi angled cut sloping down toward the muzzle end. The marketing hype said the quit the endurance test at 5000rds with no failures. Either way i got it it's been great and they have been making them for years now
I’ve actually had two BCGs gas keys come loose, one being an early Fail Zero NiB BCG. I can’t remember what the other was but it was a plain basic one. I got an LMT BCG in my main AR that hasn’t had an issue yet and I have a lightweight VDI BCG that has their Lifecoat coating and the gas key is actually integrated into the BCG so there are no screws that can loosen or need to be staked. With that VDI BCG, it is one less worry.
I would disagree with the title of the article that these are the 10 best. A few definitely deserve to he there, but not all.
I would have liked to see mention of enhanced bolt carrier groups like the lantac or radian that have different dimensions and can help improve accuracy. Additionally I would recommend other bolt materials like the sharps that's made out of s7 tool steel, or JP enterprises who makes amazing products like a variable mass carrier, and enhanced bolt that has a different lug cut to ease lock, strengthened cam pin hole, and low friction ring seals to reduce wear. I also agree with a lot of others here that cryptic coatings should be considered, they are the slickest bcgs I've ever used with the lowest friction on the market. Their mystic black has a friction coefficient of 0.01... for comparison NiB is 0.5-0.8, DLC is new and its 0.02-0.15(something else to consider when looking at coatings), TiN I believe is 0.45.
I'm not affiliated with any of these brands, just things I've learned while building. Otherwise I really enjoy your articles, thanks.
Thanks Farkosh, lots for me to add in the future update. Definitely Cryptic since I've seen several people mention that already.
Farkosh, I am with you on this. The title should read, “These are the 10 best that I use since most of them are affordable.” I use and have used a lot of the different BCGs out there, both cheap ones and high priced ones. I make it a habit of trying everyone I can get my hands on personally. Currently I’m using BCM, F-1 Firearms, Cryptic Coatings, Lantac, JP Rifles and a few others. I find the Cryptic Coating BCG to be slickest and easiest to clean of them all. Each one of them have their place whether it be light weight for competition ARs or ones that work better for silencer use. I had to go through several different BCGs along with several different manufacturers to find one that cycled correctly in my 45 Raptor. And the one thing that was not mentioned that has a big impact on what BCG works best in what AR is whether or not you like keeping your ARs dripping in oil or dryer than most. So once again we get a list of someone’s opinion on what they think are the best BCG, ask 1000 different people and they’ll probably give you a 1000 different lists.
I used Toolcraft nitride bcg’s for my last 2 builds and have been more than happy with them. Easy to clean and a great price point.
^That. Right there.
Not sure how he failed to include Toolcraft. Aren't they the OEM for some of these Mfgrs? Also DLC coating is becoming popular and more common.
My understanding is they are OEM for BCM BCGs.
As someone who's tactically thrifty, I've only used Toolcraft BCGs in my builds(*), and have never had a problem. I was surprised they weren't included too.
* One is actually a BA BCG, but it's really a re-branded Aero BCG, which in this particular case is really a Toolcraft BCG.
The fact that no Cryptic Coatings BCGs are here means the whole article is useless
^^Nuff said^^
There will only be one bolt that I will use for the future, and it comes from Sharps. The BCG's above are all great options, but the bolt itself is a different story. :)
I am reading thru this article on bolt carrier groups. I am interested in a full auto BCG. I was wondering if I need to purchase a specialized upper to fit a full auto BCG since the back of it is longer and a smidgen heavier than standard ones?
Nope, SA and FA BCGs have the same dimensions and will fit in any standard AR-15 upper!
I LOL’d at the Magnetic Particle tested “bolt” picture. That was absolutely hilarious. Well done sirs. Also, to everyone, be careful with NiB bolts, and be sure to check headspace on every build. I’ve read numerous stories of stacking tolerances from some manufacturers, due to the thickness of the coating. Please check the headspace on every build. Go/No-go gauges are too cheap to make excuses about safety concerns.
PewPew, it’d be great if you could do an article about headspace, its importance, and how to check it. I’ve run into more semi-experienced shooters than I can count who had no idea, or only a vague idea, what headspace is, and had never checked it on any of their bolts/barrels/rifles. I cringe every time, then pull out my handy dandy gauges and prepare to give a lecture.
Yes what he said. NiB coatings do add thickness and most bolt makers pay attention to the bolt face but for get about the lugs, where a small buildup of carbon will lock your bolt up. Also NiB has less friction does not mean it does not need lube. The AR15 use the lube not only as lubricant but also captures particles. Its great NiB will run fine with a small amount of lube I recommend using normal amount of lube.
what makes the BCM bcg better than the bcg it copies COLT
All Colt makes these days are the extractors, The pony is a mere shadow of once greatness..
Are the Phosphate bolts stronger than both NiB & TiN? I really like the idea of easier cleaning, but if the hardness isn't as great, then since I have to clean anyway... I've found NiB & TiN BCGs for $100 & $120, respectively.
Nothing beats POF milspac + BCG...
What about lwrci's keyless BCG
So maybe a dumb question, but a new BCG makes it easier to clean and maybe less recoil, right?
So if you don't mind cleaning your current and the recoil isn't a big deal, what other reason is there to change?
Just asking since I'm enjoying learning about all of the fun you can have with the adult lego set!
If it does what you want it to do, there isn't a need to change. A better one might last longer or be a bit more reliable in bad conditions, but that depends on what you currently have Vs. what you might upgrade to.
Full auto bolt carriers are essential if you run a fostech echo trigger.
sorry I've owned a lot of BCG's and any discussion of the best BCG that doesn't include Cryptic Coatings at the very top is not worth reading. Easiest to clean, best customer service, and no, I'm in no way affiliated with them. I have put them in all of my AR platforms in the past 2 years.
I agree to that!
Thanks Mike, I've actually never heard of them!
Had never heard of them. Thanks for sharing.
and liking what I found on their site.
Cryptic is the best Ive ever used as well. 15k rounds and counting on my carbine. Been throw 4 barrels, but the BCG looks near new.
4 barrels in 15K rounds?? wow!! Please tell us which barrels so we can avoid!
what makes them better than Colt,Bcm because they might be easier to clean? Let me remind you that a quality Ar will run very dirty as long as it's wet.
But with one of Cryptic Coating BCGs you don’t have to run them dripping wet which is a definite plus when running suppressed.
I just purchased a nitride (sometimes referred to as Melonite) finished BCG. It is a surface treatment that unlike coatings will never chip or flake off. It has the lubricity of the NiB, it is cheaper than NiB and it cleans up every bit as easy.