Which 9mm AR Bolt? The AR9 blowback bolt I choose and why.

Taking a look at the various 9mm AR bolts I own, the ones I choose over all the rest, and why. Comparing Alpha Shooting Sports, Foxtrot Mike (FM-9), Taccom, Mercury Precision, Brownells Hybrid, Kaw Valley Precision, and B. Kings Firearms. I am not affiliated with or paid by any of these companies in any way, and I do not sell anything.
More information including links can be found at Blowback9.com.
Article: blowback9.word...
I wear ear plugs, or muffs, or both, in every shooting video.
Disclaimer:
Blowback9's videos are filmed at a private shooting club in a controlled setting under the supervision of trained professionals. Blowback9's videos are for entertainment purposes only. Do not try to recreate or mimic anything seen in Blowback9's videos. Do not act in any way based upon any of the information found in Blowback9's videos. The accuracy of the information in Blowback9's videos is not guaranteed or warranted in any way. You, and only you, are responsible for the consequences of your actions. By watching Blowback9's videos you agree that we will not be held liable for any injury to yourself, others, or property resulting from attempting anything based on what is shown or described in these videos.

[@-kepha8828]

What's the odds. I googled B kings firearms AR9 BCG, and their shop is only 1 hour from my house. Yayyy

[@Blowback9]

Nice!

[@rickkirby6856]

Brother... You are an endless source of knowledge and I have watched ALL of your videos on 9mm ARs! I have built other variants of the AR for years with great success, but I have been stumbling around trying to figure out how to make my 9mm ARs reliable. Your videos on the buffers and this one on the bolt has me buying 1 new bolt for one gun and a different buffer for the other. Kudos to you and keep up the excellent work!

[@michael9r9rsBlasters]

Great video! I know SOTAR recommends only having either the O-Ring, or the Rubber post, not both. That being said he really only focuses on normal ARs, not AR9s so I can see having both with that extra extractor tension being beneficial.

[@ronaldprovencher7570]

9mm AR Bolt,,Brownell works great ,, no problems

[@jeremiahcherry5283]

This was a great video. I truly appreciate all the variants! And learnt me quite a bit. Thank you.

[@jay_daniels1388]

I used the mercury precision after I watched your video. Got a good deal on it and it worked fine with a JT9 lower . No problems and didn’t have to make any tweaks.

[@mattrosenquist7414]

My favorite has been the Angstadt Arms 9mm bolt

[@Blowback9]

Related article on Blowback9.com: blowback9.wordpress.com/2023/11/09/9mm-bolts/

[@danielhess39]

Thanks for the knowledge, as always!!!

[@stefanagiovlasitis2669]

You have won yourself a subsciber . Well done good sir. Thank you.

[@Blowback9]

Awesome, thank you!

[@rootpass74]

Thank you for your great videos! Subscribed!!

[@rucktrucktrekker8139]

Excellent content very informative

[@scott2228]

Great info. If my FM9 BCG ever gives me an issue I’ll switch to the BKF. I’ve got a few of their ARs. Looks to b quality parts.

[@chuckst98]

I recently bought an Aero 9 lower and 7.5 and 16 inch uppers and I bought the Kaw Valley Bolt and Buffer/Spring for both uppers so I’m glad the KV bolt is recommenced.

[@calicojack556]

Great video and a must watch if you are shopping around for parts. FWIW. I bought an upper that has the Mercury bolt. The Mercury bolt that I got is a about 13.5 oz and the Kaw Valley (which I also have) is about 14.5 oz.

[@philrainey805]

I have tried the Taccom bolt and I'm not a fan. I have used the Faxon and it runs 100%. Currently using the Stern Defense bolt and it is also 100%. A lot of guys running competitions run the Stern. It has a Mag-Phosphate finish which is superior to the nitrate finish found on the majority of bolts. Cost runs about $120, bought mine on sale for $100.

[@PlataniumRacer]

Happy with my Faxon as well at about 500 rounds

[@TheManFromMA]

I’ve used foxtrot mike but lately I’ve been using fail zero

[@xavirey-ie9qc]

Thank you for the knowledge.

[@furfordpainting]

Great video, love all the information you share. I have a psa ar9 Glock lower and upper with KVP bolt, buffer, and extra power spring and it runs fantastic! Has not failed once with numerous types of ammo both factory and reloads, semi and bianary fire, ect. I think KVP is a great company and has some of the best ar9/pcc products on the market. I have used a king b and taccom bolt in it and nothing ran as smoothly and reliably as the KVP combo. I think the extra power spring works well with a suppressor with the added back pressure but unsuppressed might be a little stiff.

[@gcflower99]

Great video for me, the PCC 9 newbie!! New subscriber, also! I appreciate your work.

[@jumbomrmeaner3016]

Thank you

[@Mil-Spec_Mike]

Have you considered reviewing Macon Armories 9mm bolt, along with their buffer with your spring of choice. Going to build another and was curious how they faired with all of Rudy's tinkering.

[@Blowback9]

I have his buffer and it seems to work well to reduce bolt bounce. I believe his bolt uses an internal extractor, which I avoid. Rudy is a good guy and his barrels are top notch.

[@stevegillespie6424]

Springfield SV 9 is very similarly looking (at face value) to the FM9 bolt

[@g.barrett8410]

Good info, Thanks for posting. I like my Foxtrot Mike 9mm bolt best because it has the foreward assist cuts BUT I don't currently use it because of that weak firing pin spring... is there a replacement spring for the FM firing pin spring that would be safer?

[@brianwhynot]

Harbor Freight sells a spring assortment that comes with a 7/32 x 11/16 spring that fits.

[@antoniomontoya9680]

@@brianwhynot that only fits the older model bolts. The newer ones are 3/16"

[@Blowback9]

A few of us are testing a 5mm (about 3/16") spring that may work as a replacement in the newer bolts... uxcell Compression Spring, 5Pcs 304 Stainless Steel, 5mm OD, 0.5mm Wire Size, 25mm Free Length, Silver Tone a.co/d/9SsKSRK

[@rascaille3792]

I had a fm45 bolt that wouldn't extract and it was missing the bottom feed lip. I got them to send me a new bolt and it had feeding issues and the extractor stuck out past the bolt face, bending all the brass. Finally I bought a kvp 45 bolt and it worked perfectly. I stay away from fm now.

[@UncleDanBand64]

I love the simplicity and reliability of blowback ar9's. I am going back down the rabbit hole. Pretty much the hottest round I have ever shot is 124 NATO. That round borders on +p pressure. I have had zero issues there. I am about to start testing with the 90 gr Underwood +p+. I am going to start with the a 11oz buffer. What got me to thinking it would be OK is the slew off 10mm blowback hitting the market with 8.5oz buffers. Thoughts?

[@Blowback9]

I don't mess with +P+. +P+ just means "more than +P" because there's no set standard. How much more is anyone's guess. If it were me, I'd start with no less than an 11oz. buffer.

[@UncleDanBand64]

@Blowback9 thank you for your reply. I have really been enjoying your videos and your website. I tried to get the KAK tungsten bolt weight you talk about. Out of Stock. Also considering the Kyn shot and the slightly longer tube. That would add about 5 more ounces I think. I have used those weights before to quickly jump from H3 to lower pressure 9mm and shorten the stroke. I have that already. Your channel is a great resource. Thank you and Happy New Year.

[@UncleDanBand64]

@Blowback9 Well reporting back. My AR9 ran 124 +p like a champ. Increased the velocity by 135 fps over the box. The ammo I ordered for the project was Underwood +p+ extreme defender 90 gr. It didn't make it yet. I had a box of Underwood +p+ 147. Against my better judgment I tried that. First two rounds no problem. 3rd round ruptured the case and blew the extractor off the bolt. That was with a Kaw Valley bolt. Stern Defense 11oz Buffer. Carbine tube and Spring. I think it would have been OK with a Kyn Shot weight and the Tungsten KAK bolt weight. That being said. I think I will add the longer tube, Kyn Shot and Tungsten and consider the Underwood +p 68gr Exteme Defender to be the maximum I am willing to go. Just giving you a data point. Thanks.

[@Blowback9]

Thank you for the update, and sorry to hear about the rupture damage. +P+ is sketchy stuff.@@UncleDanBand64

[@UncleDanBand64]

@@Blowback9 lol, well. Science can be dangerous at times.

[@tonyrillieux6885]

Maybe next time you will have a Faxon bcg

[@Blowback9]

From what I've seen, I'm pretty sure it comes from the same OEM supplier as my preferred 3 on the left (which means it's the same but has a Faxon logo on it).

[@GRodriguez94]

​@@Blowback9I just bought and received my Faxon bcg. It has the same geometry and features as the 3 on the left. It also weighs 14.6 oz

[@stevegillespie6424]

Interesting. I must have an older KVP bolt. It has a 1911 style extractor. It looks alot like the one on the far right but it has the intact foot on the bottom.

[@Blowback9]

The different companies change suppliers over time as the bolt tech improves. I really hope the current KVP design sticks for a while. It seems to have all the best features.

[@stevegillespie6424]

@@Blowback9 Yup very typical. I built this one in 2016 out of a myriad of brand names. It runs good, with the very occasional failure to eject. I havent run it since your video with the ejector adjustment how to, which I modded mine following your advice, by bending into the channel, and refacing. I decided to order one of the BK bolts to give it a go, and see if there is any performance changes. That outfit (BKF) ships quick, with great/fast updates!! Great info you provide. Keep it up. Happy to be a subscriber.

[@4244john]

I have an issue with the aero EPC-9 ejector. It runs phenomenal when it doesn’t stove pipe and I followed your Wordpress recommendations. Only issue I’m having is the ejector does not sit high enough to be flush with the bolt and there’s a tiny gap between the bolt and ejector. I noticed it barely bites the casing as it ejects. Since it’s an aero, I’m unable to adjust it accordingly due to having a hole at the bottom of the ejector that acts as a retaining pin when tightening. I can’t seem to find an ejector that’s not new frontier style.

[@Blowback9]

I just bought an Aero receiver set. I'll be working on the best way to adjust the ejector soon.

[@4244john]

@@Blowback9 thank you so much!!

[@4244john]

@@Blowback9 so, I ended up buying a New Frontier Style ejector from Joe Bobs Outfitters. They’re not drilled and I was able to adjust it higher into the BCG rail, dimpled it and tightened it using the set screw on the epc 9. I’m waiting on the weather to clear up and I’ll keep you posted! I’ll send some coffee your way

[@Blowback9]

@@4244john Looking forward to hearing how it goes. I need to get that ejector to test.

[@user-xz2yi1yj4p]

my KAK enhanced bolt works great so far. you definitely pay for it though. I think its like $170

[@NebulousCat]

Do you have any thoughts on the PSA Gen4 9mm bolt?

[@Blowback9]

Some of the details I can see in the photos in the reviews make me think it may be the same design as the Mercury Precision, but that's just a best guess. I dont have one to look at.

[@Solidbuilthomes]

What about faxon bolts and barrels.... they've been working great for my AR9.... I installed a taccom feed ramp and have never had a jam since 🤙

[@Blowback9]

Good to hear! Faxon bolts are fine, but last check their barrels didn't have the best feed cone. Macon Armory, Aero, and Ballistic Advantage EPC barrel feed cones don't require an additional feed ramp because the cone is so wide - it acts like its own feed ramp.

[@joshuasalame]

I can speak to the not best feed cones with faxon barrels 😊 Mine didn't function, so BA on the way.

[@Solidbuilthomes]

@joshuasalame yep, I had to install the Taccom feed ramp to make it work.... otherwise it constantly jammed.... But, now it runs flawlessly....

[@-kepha8828]

I have a 5.56 lower and a 9mm upper. I plan on using endomags for my 9mm rounds. Is the BKing BCG still a good choice for endomags on a 5.56 lower?

[@Blowback9]

I think so, yes!

[@jrtatonka]

Any experience with the Stern Defense bolt?

[@Blowback9]

No, sorry!

[@douglasmcarthur7986]

I use a nickel plated Stern .40 S&W bolt in my 10mm BB. Works great, no complaints. Tad expensive.

[@scottc3029]

Why are some of the "gas keys" lug fronts vertical and some are slanted?

[@Blowback9]

Great question! Charging handle attachment point. The slanted ones use the flat front bottom edge of the angled key for the charging handle to grip. The vertical ones have a flat shelf on the front of the bolt for the charging handle.

[@marquesemitchell7099]

Thank you for your knowledge and information! What bcg would you use if you are using MEAN Arms adaptable mags?

[@Blowback9]

The same ones I selected in the video.

[@robertoriveralozada5115]

Do you know about PSA AKV 9mm blowbacks? If so what you recommend for blowback prevention.. your opinion.. 🙏🏽

[@WethePeople-yb8jo]

any idea about cryptic coatings or fail zero nickel boron bolt carrier? how is fouling vs 5.56

[@papap6255]

Hey blowback, would you happen to know if alpha shooting sports ever made changes to their uppers? I ordered the completed upper before seeing your website and videos about them 😭

[@Blowback9]

I don't know - I bought mine several years ago. It may be fine, it may not. Rudy's feed cone work should get it going if it has problems feeding, though.

[@junmalenab682]

Can you review the different delay systems available for 9mm blowback rifles?

[@Blowback9]

I wish I could, but I'm only one person with a small personal budget for my videos and tests. Nothing is monetized - too many rules.

[@grendeldog01]

Hi Doug, off topic to this vid but just wanted to ask. Do you recommend the Stern Defense mag well adaptor or something else? Plenty of reviews of them, but I trust your down to earth advice! Thanks!

[@Blowback9]

I tried the Stern and didn't like it because it changes the position of the mag release and the ejector is hardened and cannot be bent or adjusted into the proper position for consistent ejection. However, many people do like it and use it without any problems.

[@user-db8hh3dg7w]

Do the brigade mfg ar9

[@scubadkins]

One of my bolts is from quarter circle 10. Any experience with those?

[@scottc3029]

What is the difference between a Colt bolt and a Glock bolt?

[@Blowback9]

The contour of the bottom where it pushes the cartridge out of the feed lips is different. The Glock feed lips are more narrow, so the feed lug on the bolt needs to be more narrow to fit between them. Hybrid bolts (most new designs are now hybrid) can work with both mag types.

[@StephanCzajkowski]

Could you do a jp bcg?

[@alanorther]

I'm new to the AR-9 realm and just purchased an Aero EPC-9 upper and lower. Will the Brownells Hybrid, Kaw Valley Precision, and B. Kings Firearms bolts be able to utilize the LRBHO of the EPC-9? I'm not use if that upper will hold open any bolts, bolts designed for Glock, or only special bolts?

[@Blowback9]

It should work just fine with one of those bolts.

[@patrickreddy5332]

where is the CMMG?

[@walt3r88]

What about angstadt arms? I happen to have one is why I ask.

[@Blowback9]

I just got one for testing. It appears to be the same as the B. Kings style of bolt. It should be good to go!

[@walt3r88]

@@Blowback9 right on. I just picked up a 10 oz buffer for it as well.

[@walt3r88]

Took it out and found the bolt hold open broken. It didn’t lock back the last time I had it out and now I wonder if it was the heavy 308 spring. Either way, it ran way better with the heavy buffer and carbine spring.

[@Blowback9]

@@walt3r88Good to hear it's running better!

[@siniquezu]

What is the weight on those bcg?

[@Blowback9]

BKF, KVP, Brownells: 14.7oz., Mercury: 13.7, Taccom 13.6 , FM9 13.9, A.S.S. 15.5

[@richness1644]

Will a B Kings bolt work in my FM 9?

[@Blowback9]

Yes, it should!

[@From973to904]

I think an external mic would greatly help your content

[@Blowback9]

Yea... I'm not a great videographer. I need to figure out if the camera will work with one and which to get.

[@ryanblackgoat4741]

I have a factory colt 6951...will the kawvally or brownells bolt work it my rifle?...im new to ar9s

[@Blowback9]

Either one should work just fine, but you'll need a heavier buffer than the 5.5oz Colt original. I'd go with a KAK Industries 8.4oz., and remove the spacer from the back of your buffer spring if there is one. Some have a spacer, some don't. More: blowback9.wordpress.com/2021/08/09/what-9mm-buffer-do-i-need/

[@antoniomontoya9680]

I took your advice and replaced my ftm with a bkf. Did anybody come up with a solution for the ftm slam firing issue ?

[@Blowback9]

Several people have been looking for a stronger firing pin spring, but the channel for the spring is very narrow and it's tough to find a stronger one that fits. I'd also avoid using the FM .308 recoil spring and use a normal carbine spring that doesn't slam the bolt forward as hard.

[@antoniomontoya9680]

It only does it with Remington target ammo. I would be willing to bet your gentle recoil system takes care of it. Stay tuned

[@slavicgondola1817]

What do you think of the KAK 9MM enhanced BCG ?

[@Blowback9]

I don't have any experience with it, but it looks like a blend of older and newer designs. For the price they're asking, I'd look elsewhere.

[@ross8270]

What’s up with that taccom carrier key , looks super short. That safe ???

[@Blowback9]

It is safe. It allows the bolt to be removed without pulling the charging handle. Opening the upper and tipping it allows the bolt to slide right out.

[@MrTartarSauced]

Which bolt is "super safe" compatible?

[@Blowback9]

Not positive, but all these should work.

[@user-nu6zn1br6w]

What do you think about cmmg blowback bolt?

[@Blowback9]

The old Mk9 blowback bolt? It looks ok, except for the internal extractor. I've had too many problems with internal extractors to trust them, but that's just me. It should work just fine.

[@diceydie-c]

What do you think about Stern Defense bcg? From what ive read about the bolt it sounds really good

[@CaFFeineSouLja]

how much does the bk firearms bcg weigh?

[@Blowback9]

about 14.5 oz.

[@CaFFeineSouLja]

@@Blowback9 thanks do you think using the kvp 10oz tungsten buffer will be ok since that would put the total at 24.5oz or more?

[@Blowback9]

Experiments show 9mm should reliably cycle at least 37oz. total with any commercial barrel length. 24.5oz will be fine. I run one of mine at 27oz. regularly.