Three words regarding this video and Blowback9: TAKE HIS ADVICE. I'm a first time AR rifle builder and if not for these videos and the information on his website I would probably NOT have had the experience I did. I spent 4th of July 2024 assembling an AR 9 I had purchased in parts starting in March 2024. I followed the advice of Blowback9 regarding barrel choice, bolt carrier group, buffer weight, spring, and ejector tuning when I very carefully assembled my AR 9. I spent a good hour and a half tuning my ejector and it paid dividends I'm sure. My first trip to the range with my AR 9 : 1) My AR 9 Shot Fiocchi and Remington115 GR FMJ ammo flawlessly. 2) My AR 9 Shot Fiocchi 147 GR hollow points flawlessly. 3) My AR 9 Shot mixtures of FMJ and hollow points flawlessly. NO WAY could I have accomplished 1): 3) without watching the videos and visiting Blowback 9 Website. Thanks for the videos ! They are a God Send ! Kudos !

I have been a frustrated owner of a 9mm AR for years! It took a lot of time and research to get my 9mm AR running reliably. I am glad to see that you are putting all the important information in one place for future 9mm AR owners to find easily. I wish your page existed ten years ago.

Damn. I’ve been chasing my ejection issues the past two range sessions. My ejector was a point and at the bottom of the bolt. Squared it off, moved up and in and never ejected better. Thank you sir.

I was LITERALLY about to ask if you were the guy who runs that awesome site full of great info and you answered it on your first sentence. Subscribed.

very good video. thanks for including picture of ejector alignment.

5 star videos

I was having ejector issues with my AR-9, it was low but I recently adjusted it to how you showed. Haven’t got to test it out yet. Great video and information

I really appreciate all of your research! I was able to build my 9mm AR upper with 100% function and reliability first try with your info and reply's. Here is my build for anyone wondering: BKings Bolt Carrier Group, BKings Carbine Buffer Spring, Kaw Valley Precision 10oz 9mm Tungsten Buffer, Ballistic Advantage 16" 9mm Barrel, Spike's Stripped 9mm upper receiver, Spike's Tactical Battle Trigger, and MeanArms Magpul Pmag 9mm conversion. Recoil feels better than my sig 516 upper.

Very clear and concise information. This is the best short video on this topic I have been able to find. Thanks!

My 1st AR 9 buiran flawlessly accept, as you stated. JHP tried modifying the feed cone and also tried installing a feed ramp it was a nogo. Installed a Taccom supper feed barrel problem solved . Great company great customer service

Great video! Wish your video was around when I built my AR9s. I had to learn all this on my own. Good job!

I just put my 1st 9mm together, and it would NOT shoot. I watched this video and did what you said. The thing works like a top now! Thanks

I rarely comment on youtube content but this is great info and well presented. I’ve learned so much from this video alone. Thank you for what you do.

Great video, I actually read your articles online before seeing this video. I’ve definitely seen compelling evidence to support both sides of this topic. I plan on doing some testing with my FM9

Good stuff as usual, happy to be a subscriber. Going to have a look a the ejectors on mine now. Can't really remedy the feed cones.

OUTSTANDING GREAT information very clear to the point!!! good to know going into the 9mm AR, been doing Reg 556/300 and this has def opened my eyes to all the upcoming thank you for taking the time to explain

Helpful info. I got lucky!!! I purchased a built Foxtrot Mike AR9 upper and then their factory built lower separately. I put the 2 together and it’s been 100% reliable from day 1. After adding a suppressor, all I had to do is add a heavier buffer. (45ACP) 7.50oz Going to hit the range today!!! Enjoyed the vid.

This is the way. My Aero EPC9 is now running like a scalded ape without a single issue since ditching the (Aero BCG) for a proper one with the feed lug and 5.56 extractor.

Excellent content. This is the best part of youtube, when you learn valuable info. My ARV has been sitting in the safe because of problems that I think I can fix now. Thanks

Thanks for putting out this great information. I took your advice and bought the kak gold top buffer. While I was at it, I also bought their 9mm bolt. The bolt costs a little more than other bolts, but has a great feature that I haven’t seen elsewhere. The standard ar extractor has, instead of a roll pin, a partially threaded pin that allows you to easily remove the extractor for cleaning or replacement. I put both in my Colt 6450 and they work great, even fed a mag of hollow points.

Thanks for what you are doing!

Thanks for putting this together. I've been doing things wrong for to long. I some how was able to get a few reliable ar9's. But it wasnt easy. I had know Idea how simple the formula was. Now time to rebuild a couple of may favorites. Thank you. Subbed

Note when I say "100%", I mean it should feed, fire, and function as reliably as would be expected from a typical quality firearm. No mechanical system runs 100% perfectly 100% of the time. For simple blowback only, NOT for CMMG Banshee! More info: blowback9.wordpress.com/2022/08/18/4-step-guide-to-make-almost-any-ar9-run-100/

Very informative.... Thank you

Great presentation. Thank you Sir.

Thank you for the knowledgeable video

Great video I’ve done everything you said but I had to learn the hard way. Found your video a year later.

Thank you for your video. I just bought an AR9 8" barrel. I haven't fired it yet. I check the buffer and its 3 quarter inch long same as what you shown. I think i will buy a new buffer 4" long before going to range .

Boy howdy, did I miss out on a lot of headaches by getting a YHM upper with all these issues worked out for me. I do think I need to step back and start from scratch by weighing my bolt and buffer.

My epc9 is a frankenrifle. Sprinco buffer spring for carbine, Aero buffer like you tossed. Foxtrot Mike's bolt, NBS BARREL and LaRue trigger. Larue trigger best ever. No mim used. My first 9mm runs like mad. On magpul mags. Kingslayer with green dot and ring. Odinworks handguard.

Thank you for the info!

This dude's information has my PSA AR-V running like a champ. I use the 10oz KAK buffer and $1.75 in quarters in the tube to get my bolt within 1/4" of the bolt catch when pulled back, and it runs. I still plan to get a Macon barrel soon. Thanks!

I went to the range for testing today. Using the adapter for colt magazines I found that it doesn't like a full 20rd magazine. Seems the bolt was binding up on initial charging. First ten round group ran great. Later on I was having ejection issues but I think it was because my mag adapter was loose. I appreciate all of your videos and hard work.

Going to Subscribe now for future use after I get my AR9! lol Thanks!

First time watching your channel very informative thank you very much keep up the great work. Bought a psa AV9 that throws the empty brass 25 feet at the 1, Oclock position and bottms out the bolt very violently. Thans for the tips

Very good video! 💯👍

big stuff right here thanks! been screwing with mine few years now but I love it. trying to get them short is a problem for me put the Dead foot arms 2.5" brace on and it went nuts on me. changed the trigger stopped the full auto, got a "guaranteed to feed" barrel only feeds flat tips when I add a little oil to the cone although I noticed after the cone dried up it kept running them. so may just need a wear in. I do have a stove pipe or a spent casing left in the chamber causing misfeeds so I did notice the ejector was not snug as your pic. It took me a few times but it looks a little more snug. will try this out at the range tomorrow. I bent a little too much and was hitting one of my dummy rounds causing it to nose up and jam. took a little off seems to be better now. dead foot arms has their "modified cycle system" which is a spring within a spring setup. diff weight springs to play with. I have since stuck with 165gr subs I load myself as they are gentle on the gun and it runs. I stay away from supers just because it seems so ruff on the entire gun. stuff was coming loose at one point the upper pin housing actually broke and angstadt sent me a new one. so running supers with the DFA is a no for me. I might have the spring setup good now and with the trigger correct maybe I can try again but for now it's cushy subs. I run a can and that seemed to magnify the issues as well. thanks for the vid! liked n subscribed sir.

Great video! Thank you for your service to the community.

OK, I was having a problem with a Glock 33 round magazine loaded with Berry's 124 gr hp bullets. The bullet would just jam into the bottom edge of the barrel chamber. I replaced the barrel with a Ballistic Advantage 8.3" EPC 9MM barrel. I polished the face for good measure. It now feeds the Berry bullets with no problem. I did notice a little dent on the edge of the bullet but they are softer than jacketed bullets. I am a happy boy. Thanks!

I want to share an experience I had. I decided to use a standard AR lower (Spikes) with a magwell insert (from KAK) for a Colt-style magazine. I had two problems; one is the KAK insert is held by two set screws that are inadequate for the job (yeah - I know - I can dimple it - but I don't want to mar the lower). Also, the mag release was not able to engage the magazine very well because the insert created a much thicker wall. The KAK insert, to make matters worse, did not fit tightly. There was quite a bit of air between the KAK product and the lower. So I got a Hahn Precision dedicated magwell insert which fits like a glove and seats tightly. Even with that - the mag release was not engaging enough. I ended up getting the CMMG ambi mag release that extends MUCH further into the magwell and now I have a much better setup. The ambi mag release is also a nice touch. Now, anybody want a free KAK magwell insert? ;)

Thank you

Thank you for taking the time to put out this information! New to the blowback AR9 world and have recently purchased a Bear Creek Arsenal side charge blowback upper with 16" barrel. Do the same rules apply for the buffer and buffer spring when using a full length buffer tube? First range trip using the provided buffer & standard AR buffer spring. The side charging handle and was broken off within the first 20 rounds. Just wonder if there's something I'm overlooking.

I saw a kit for a colt 9mm smg the other day. Its a colt 9 mm smg that jus has a little square cut out of the lower where the hammer and trigger pins go, and a square cut out where the auto sear pin hole was.

I like to use an Odin works barrel, tool craft bcg, with armaspec buffer. Great combo runs flawlessly with the mean arms magazine conversion.

Built my own a couple years ago doing my own research Arv builders kit Macon Deadblow buffer 8" Macon barrel Franklin armory binary trigger andspring Feels like a machine gun

Awesome!!!

You're sharp

Excellent content sir. Much needed information for the frustrated masses. Have you found the feed ramp that is used by Taccom in their barrels to be beneficial? Overkill?

Great video!!! I bought a Macon Armory "deadblow" buffer, Wilson Combat flatwire carbine spring, and a Cryptic Coating bolt. Total weight is 21 oz. Is that 1 ounce going to present any trouble?

My FM9 does not reliably feed hollow points. In the process now of finding a new barrel. Thanks for the info!

Not a ton of rounds yet but my budget build has been 100% so far. My recipe: -Spinta barrel and upper receiver -FM 9mm bolt and buffer -Standard carbine spring -Standard Anderson lower receiver -Standard 556 mags with Endomag 9mm insert.

Brownells also has the correct PCC buffer.

My AR9 is my favorite build so far and runs flawless Palmetto kit, Aero lower, 8oz buffer, was 4in barrel with kit swapped to 7in CBC ind barrel, law tac folder, Endo mag conversion

nice

Hey BB9, I'm running an 8.5" AR9 suppressed and I recently experienced a double at the range. What buffer spring and buffer do you recommend for my rifle? Thanks!

Thanks again. Yup, my homebuild ejector was out of alignment, and rounded (PSA, dedicated Colt mag lower). Went ahead and bent it into alignment. and filed the face of it flat and as square as I can get it. It is in much better alignment with the ejector channel/bolt face now. My Saint Victor 9mm ejector, was already in very good alignment with the ejector channel, but the tip was rounded, so I filed it flat/square, as best I could. Tidbit about the Saint Victor, it uses a plastic/rubber spacer at the butt end of the buffer spring, with a 3.25" buffer, of unknown weight. It is relatively light recoiling, for that lower mass combo. Wish I knew what spring they use. It doesn't take much force to pull the BCG back. I'd say it takes signifigantly less force to open then my 11oz buffered, flat wire buffer sprung, KVP bolt, home build.

Hello sir! Love your insight on the ar9 platform!!! I was wondering if I want to add a laser aiming module to an AERO EPC9 would you go with the enhanced upper and handgaurd or do you think the regular threaded will hold up fine?

Do you have a video on Rifle Length Buffers? Because I cant find a 9mm buffer made for a Rifle length buffer tube. I have a CTS Aktive buffer currently in my rifle. It weight 6.5 oz. I should be receiving my PSA Gen 4 9mm upper in a couple days. So I am hoping it works.

Man glad I found your video I am having problems with double fires and have replaced the trigger group. It’s a bear creek and I know you get what you pay for lol but it does have a regular buffer that it came with. Would you have any other suggestions or things to try?

I use Mean Arms EndoMags, ejector is part of magazine.

Just installed the Wilson Combat flat wire carbine spring in all by ARs 9mm & 5.56. They all had the twang before and it is gone after I installed the springs.

But, I do have a question with all this information great information how will the result be with a suppress system? Because that will be the main goal have it.

My AR9 functioned perfectly for me after getting the heavy buffer and I added a piece of Delrin in the buffer tube to prevent the bolt from over-traveling on recoil. BUT I had a bullet Glock mag lower in my AR9 for the forst 3000 or so rounds. I changed over to a standard AR lower and tried out the Mean Arms 9mm mag conversions and the follow up shot jams straight into the bottom of the barrel, pushing the bullet inside of the case, ruining the round. I'm going to guess that I need a feed ramp. My barrel's feed cone looks to be less than that Colt style feed cone. It looks more like my KelTec Sub2000 feed cone. This feed cone works well with the Glock mags because the Glock mags hold the bullet closer to the chamber and the angle is better in the Glock mag than with the Mean Arms mag conversions. I assume the back of the 9mm case is unsupported when there is the larger feed cone? Is that the true? If it works, that's fine by me. I was thinking of just using a Dremel to add a feed ramp to the bottom of my barrel and try that. If that doesnt' fix it, I can chuck the barrel in my lathe and enlarge the feed cone.

Draco 9s smooth af AR9 jumps around like a hip hop concert

I feel defeated now after watching this because I just realized that the injector on my EPC 9 lower is one of those odd looking ones that looks like an a with a flag on it😢 is there any way to fix that will it still Bend to the right a little bit

I just bought a Foxtrot Mike lower and a PSA 8" upper. I got a 7.5 oz Macon Armory dead blow buffer and standard carbine spring. I've shot about 100 rounds including 115gr fmj, 147 gr fmj and HST 147 gr HP. It has run flawlessly so far. I noted the buffer + bolt is just under 22 oz and the ejector is slightly away from the bolt and down some in the ejector groove. There is copper rub marks on the chamber face of the barrel. I am thinking if it ain't broke don't fix it but it would also be very easy to install a Ballistic Advantage barrel, just in case. I also have a YHM R9 suppressor waiting on a tax stamp. I wonder if I should get a heavier buffer. Flat wire buffer spring is on the way.

What about the Geissele braided buffer spring? Do you recommend me changing that to a flat wire with your recommendations?

Am I frustrated with my AERO EPC inability to reliably load HP ammo? That’s putting it lightly. I even tried new BA barrel with enhanced feeding cone a few months back, but it’s still a no-go. I’ll next try the Gold Top Buffer. BTW….I tried Damage Industries Enhanced Buffer Springs in my other ARs and they’re also pretty darned quiet.

Would you ever consider a heavier spring (IE Kaw Valley XP) when shooting heavy grain (147/158) suppressed?

Good information. This vid helped me remedy a ejection issue. Question for you and all. I have a custom made by me a 12 ounce buffers both have 4 tungsten weights One the weight's do not reciprocate basically solid the other the weights move a little ie .055 of movement. I've not tested them yet but what's your advice on solid or reciprocating? Also if you suggest reciprocating weights is .055 enough reciprocating clearance?

How do you feel about the JP Enhanced Bolt 9mm and the Full Stroke 9mm SCS? I have the BA 8.3 barrel and the Aero EPC 9 upper and lower

Ive had issues with firing pin springs all being different and causing ftf when to heavy on ar9's. Even had the bolt maker send new lighter springs

Can you have a buffer that is too heavy? Would a system too heavy cause the bolt not to cycle far enough to feed another round? Does having a heavy buffer delay the opening of the bolt/chamber to allow for more muzzle velocity?

I bought a 9mm kit from PSA a few years ago that I haven't put together yet. I'm guessing that it doesn't have an improved feed cone.

is it normal for the rubber portion of the buffer to start to deform like its hitting the end of the buffer tube. i feel like the answer is no, but im not sure. its runs perfect, other than noticing this.

How about the blowback 9 mm from Springfield Armory with the colt mags?

Doug, do you know any solutions for an ejector using a 5.56 lower without using the mag well insert kit? I know the Endo mags act as the ejector, but I like the fact the mag has to be in to eject a round.

On a Foxtrot FM9 can the barrel be swapped to a new barrel of any length without making any other changes?

What about pistol length buffers? Any input there. Looking to build one.

What are the downsides to using stronger springs such as springco blue?

Great video, I am running into ejecting issues with my build. I purchased Davidson Defense "Patras" AR-15 Pistol Upper Receiver 4" 9MM 4150 CMV QPQ Nitride 1-10T Barrel 4" M-Lok Handguard along with the Aim's 9mm lower with Glock 17 mags. I have tried different ammo and still every other shot stove pipes etc. The buffer that came with the kit was the one you said to throw in the trash. LOL Would you recommend changing the buffer?

My colt runs very well .

Does any of this apply to my ar40?

I have a Christensen arms CA9mm and it has failures to feed and idk if it’s the barrel or if it’s having bolt bounce but I know it could be both it has shot halfway out of battery before

Is the percieved felt recoil softer with the gold top (heavy) or the blue top (heavier)

Im having a problem with my ar45 . It seems that the bolt is out running the mag .... Tip up malfunction.... 😊

Unfortunately I can no longer pick up a Glock magazine lower in my state. What brand of Glock magazine adapter do you prefer?

I just bought an Arv literally 3 days ago and it doesn’t get passed a one shot before feeding issues. I’m so pissed I bought cheaper guns that ran smoothly

Question. I doubt I'll get an answer as it's kind of out of date at this point but I may as well ask. How much of this applies to an AR45? I've got this AR45 monstrosity that I've been working on for the past couple years and have largely worked out most of the kinks. But, about 1 out of every 10 rounds jams up. Not like in a catastrophic way, but like the round binds up during the feed and into the chamber. Still kind of running down the list of possible fixes. Feeding from Colt/Uzi 45 mags via magwell adapter with the feed ramp, KAK weighted bolt, Aero EPC buffer. I want to try a 308 carbine buffer spring next because I know 45 is punchier than 9mm and the bolt speed might be trying to feed the rounds too fast

"AR-9s are picky and difficult to make operate properly. Here's a guide to tuning them..." Me, with a 3d printed lower and random lowest cost parts thrown together from 4 different suppliers: "Haha AR-9 go pew pew pew"

Any experience running vltor a5 buffers?

What is it about flat nose and hollow points that causes an ar9 to malfunction in that same "nose high smile imprint" fashion?

I wonder if anyone had this issue. I bought a basic KAK carbine buffer spring. It's chrome silicon with black oxide and it feels like fine sandpaper! It feels like basic rust to me! Will that smooth out quickly before it wears away at the other buffer parts?

On a 4” barreled upper would you reccomend a heavy buffer or lighter buffer since the round will be in the barrel for less time creating less pressure? Also I’m looking at the roller delay buffer would that be better than a tradition buffer? What do you recommend?

Taccom ulw barrel short stroke bolt and air buffer and you will be shooting 22 recoils😊

I am having trigger resetting issues . It fires and ejects and chambers next round but trigger will not reset have kak buffer and spring. Mil spec trigger group what would you suggest thank you for your help

How sure are you on ghost firearms having an enhanced feed ramp I just ordered my elite upper and it’s flat

Ppl.would probably freak out if they knew how i put mine together..lol..had problems but did watch another video about problens...follwed it pefect and never had anymre problems...put a stack of quarters in my buffer tube..problem solved..

I just used a off the shelf barrel..runs everthing i throw at it

Been using the Endomag, everything ran great for the first 100 rounds then it started double feeding and not ejecting properly