View Full Version : Best brand/source for bolt only, no carrier?
What is the best brand and source for a mil-spec Carpenter 158 phosphate 5.56 bolt by itself, not a complete BCG?
I did not post this in the where-to-get-it thread as I think it may entail more discussion.
SOLGW, BCM, Colt are solid choices. Between those three flip a quarter.
I’d probably pick up a few of these while they are on sale.
https://www.brownells.com/gun-parts/rifle-parts/rifle-bolts-bolt-carrier-groups/m16-5.56-bolt-assembly-nitride-mp/
I don’t know about best, but for bolts only, some of the best options are more limited. IE: Sionics
I now see this isn’t C158 but 9310 so doesn’t fit your stated requirements.
SOLGW, BCM, Colt are solid choices. Between those three flip a quarter.
Which vendor has the best price?
I’d probably pick up a few of these while they are on sale.
https://www.brownells.com/gun-parts/rifle-parts/rifle-bolts-bolt-carrier-groups/m16-5.56-bolt-assembly-nitride-mp/
Have you used that one?
Which vendor has the best price?
Have you used that one?
Yep. I had one as a spare and used it in a more recent build. Not a lot of rounds down that particular barrel however.
If you are stuck with C158 I’d probably wait until these are in stock and maybe use one of those in the interim and toss it in your spares bin when you can find a good C158 in stock.
Pickings seem pretty slim for C158 bolts only, that are actually in stock. Good or bad quality.
https://sonsoflibertygw.com/shop/solgwbolt556158c/
Pickings seem pretty slim for C158 bolts only, that are actually in stock. Good or bad quality.
I'll keep an eye on the SOLGW page. I am under the impression that C158/phosphate is a safer bet for "duty grade." I remember reading that the critical bores in nitride carriers are incorrect more often, presumably because they were manufactured with allowance for hard chrome (not applicable here but still a point of reference), and that 9310 bolts are more likely to have heat treatment issues than C158. I am open to the existence of a known-good nitride 9310 bolt.
I should have read more before posting.
Carpenter 158 is a proprietary alloy, and only available from Carpenter Technology. If you want some, you probably have to get a few tons of it. AISI 9310 is non-proprietary and available from many different foundries, in smaller quantities, and probably a lot cheaper. Many AR bolt manufacturers make bolts from 9310, and they work just fine and last just as long, but they will never be "proven" until somebody with really deep pockets reaches into those pockets and funds a serious test of the two bolts. And, the only folks with pockets that deep have no incentive to conduct such a test, because they have something that works, either 158 or 9310.
Damn, I even posted in that thread. My memory is not what I wish it were.
Any nitride/melonite treated bolt is inferior to a bolt that has been properly heat treated.
So I guess for the moment 9310 is in but nitride is out. lol
Well, you could grab one from us.
https://blackrivertactical.com/WP/BRT-M4A1-Bolt-Assembly-Kit-C158-HPT-MPI-p469551782
What is the best brand and source for a mil-spec Carpenter 158 phosphate 5.56 bolt by itself, not a complete BCG?
Noveske
https://noveske.com/products/5-56-300blk-bolt/
Well, you could grab one from us.
https://blackrivertactical.com/WP/BRT-M4A1-Bolt-Assembly-Kit-C158-HPT-MPI-p469551782
Not too bad with the extra parts. What extractor spring does it come with?
constructor
05-14-23, 20:41
What is the bend brand and source for a mil-spec Carpenter 158 phosphate 5.56 bolt by itself, not a complete BCG?
I did not post this in the where-to-get-it thread as I think it may entail more discussion.
Microbest, pretty sure BCMs bolts are made by Microbest. If not they are using programs with exact same tool paths.
Well, you could grab one from us.
https://blackrivertactical.com/WP/BRT-M4A1-Bolt-Assembly-Kit-C158-HPT-MPI-p469551782
I didn’t see these. Great option for you D-Man.
You can pick up a complete Microbest BCG from PSA for $100. Seems like the easy button move. They call it the "Fathers of Freedom" BCG, presumably as a play on Sons of Liberty. Specced with a Sprinco extractor spring, properly staked, etc. I have one as a spare, and though I haven't used it yet, it certainly looks GTG.
ETA: School of the American Rifle has a video of measuring out the BCG, and his sample was GTG. FWIW.
I have a Toolcraft BCG in my M16 and have not had an issue.
I’d probably pick up a few of these while they are on sale.
https://www.brownells.com/gun-parts/rifle-parts/rifle-bolts-bolt-carrier-groups/m16-5.56-bolt-assembly-nitride-mp/
I don’t know about best, but for bolts only, some of the best options are more limited. IE: Sionics
I now see this isn’t C158 but 9310 so doesn’t fit your stated requirements.
Which vendor has the best price?
Have you used that one?
I have a Toolcraft BCG in my M16 and have not had an issue.
One of the reasons I use Toolcraft BCG's is that their stuff is guaranteed - forever. Since it is well known that Toolcraft doesn't manufacture their own bolts, I called Toolcraft to get the skinny on the guarantee. Their stance was if it's sold by Toolcraft, it is guaranteed. When I asked how they could tell if it was a bolt they'd used, they said after you've built a couple hundred thousand, you can tell by looking at specific things.
I'm aware that lifetime guarantees are often a gimmick to get you to buy an item with the seller figuring very few will take advantage of it, but I'm one that will.
If I was buying a spare bolt, I'd go with the Brownell's for the same reason, their forever guarantee.
JMO
One of the reasons I use Toolcraft BCG's is that their stuff is guaranteed - forever. Since it is well known that Toolcraft doesn't manufacture their own bolts, I called Toolcraft to get the skinny on the guarantee. Their stance was if it's sold by Toolcraft, it is guaranteed. When I asked how they could tell if it was a bolt they'd used, they said after you've built a couple hundred thousand, you can tell by looking at specific things.
I'm aware that lifetime guarantees are often a gimmick to get you to buy an item with the seller figuring very few will take advantage of it, but I'm one that will.
If I was buying a spare bolt, I'd go with the Brownell's for the same reason, their forever guarantee.
JMO
Yeah, when you really understand what you make (or even just inspect, but UNDERSTAND the product) you can tell... im in a different industry, but at a high level, if you are an expert in your area, you know. Them betting on their knowledge definately inspires confidence.
If I was buying a spare bolt, I'd go with the Brownell's for the same reason, their forever guarantee.
Hard to argue with that. Their mil-spec M16 BCG is $130, making the $80+ bolt assemblies seem less of a value. I would take the SOLGW bolt assembly at $67.76 but it's out of stock.
You can pick up a complete Microbest BCG from PSA for $100. Seems like the easy button move. They call it the "Fathers of Freedom" BCG, presumably as a play on Sons of Liberty. Specced with a Sprinco extractor spring, properly staked, etc. I have one as a spare, and though I haven't used it yet, it certainly looks GTG.
That is appealing but it is missing the High Pressure test. According to Mike Mihalski of SOLGW (https://www.arbuildjunkie.com/ar-bolt-carrier-group-basics-mike-mihalski/) "People don’t realize that with well-made 158 carpenter steel bolts, about 3 percent of them will fail the HP test." That's a higher failure rate than I am comfortable with so I want individual HP testing now.
There is a seemingly similar Microbest BCG with HP test from arftac.com (out of stock) (https://arftac.com/microbest-ar15-5-56-c158-mpi-bolt-carrier-group-complete/) but I don't know if they can be trusted.
constructor, is there a better source for Microbest BCGs or bolt assemblies?
titsonritz
05-19-23, 21:29
I need the opposite, a couple of carriers...no bolt.
As to the OP, BCM has some in stock:
https://bravocompanyusa.com/bcm-ar15-bolt-assembly-mpi/
constructor
05-20-23, 00:42
constructor, is there a better source for Microbest BCGs or bolt assemblies?
I don't know, I purchased direct from them but I tried to get a friend set up and he said Microbest has not taken on any new customers in 10 years.
After Blackstone Arms gets caught up and starts offering 5.56 he will take over my account with MB.
I need the opposite, a couple of carriers...no bolt.
At $55 this may be worth trying. https://www.jsesurplus.com/m16boltcarrierwithstakedkey.aspx
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