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I replaced the original mag stop / ejector (aero precision style) in my Sharps Bros Jack AR9. The original held up to several range days but the replacement lasted 60 rounds before failing to feed issues began. I blue loctited it and properly installed it so nothing should be misaligned. It was my favorite and most accurate firearm until now.

I am having this issue with my FX9 and I am using Glock, ETS, and KCI mags.

Link to the set screws I used: www.amazon.com/dp/B09D7FF137

Love your work. I've watched every video. I have a question. I have multiple SBR's so I can run whatever stock I want. Have you ever tried the KynShot rifle buffer plus one weight? That would be about 10 ounces. I notice my non 9mm SBR's are a LOT more controllable with a rifle buffer system.

Love your videos, you have saved me a ton of time using your information...

I need to adjust the LRBHO for it to work with Magpul PMAGs since they sit loosely in the magazine well and won’t lock the bolt to the rear. Hopefully that won’t over correct the issue causing problems to the genuine Glock mags

So can run the upper with out the lever at all or do you need to grind it down so it doesn’t get in the way and then reinstall?

I assume you recommend a dedicated glock mag lower such as aero over a mil spec lower with adapter, for accuracy, longevity, etc? Do you have plans to test and assess the endomags used with stock lower? So far its been a decent option for me with little issue other than Hollowpoints tipping up on feed.

I like BKF parts. I bought an "upgraded" coated mil spec trigger and it actually doesn't feel as good as the stock BKF trigger in the lower parts kit.

Those screws can come out very easily, and they are not ecactly a common type. Use some really good locktite or rockset.

I would replace the EPC Mechanism with the one from New Frontier Armory. Though they appear to be the same, the NFA mechanism has a slightly different (better) geometry, it's stronger, and doesn't require any adjustment. That being said the NFA G9 Gen2 receivers come with all the right feature out of the box; the ejector is not drilled, the ejector screws are bigger and won't strip out, the screw for the bolt and rear detent are included, the LRBHO is better, and the cuts on the lower provide perfect finger placement for straight trigger finger register when not on target/not firing.

Magpul PMAGs don’t work well with the Aero EPC9 LRBHO the slot on the magazine is a bit loose compared to genuine Glock mags the bolt won’t hold open unless you push the empty magazine up while pulling the charging handle. I just found that out today after finally got the rifle assembled. I guess it’s time for me to try bending the wire

I didn’t notice the set screw hole I used the end plate to cover it and I wish I didn’t. Can you put the link for the set screws?

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.

I've had to manually adjust (e.g., bend) the LRBHO lever on both my Aeros EPC uppers.

Yeah... I had thee EXACT same issue...

Do you own the 3 lug blastwave? If you do, what's the thread pitch? I can't find any information on it. Thanks

Where can i buy an ejector?

This channel has renewed my interest in my AR9. I got a flat wire buffer spring and just ordered a B. King bolt. I realized from one of your videos that I need to fabricate a 1cm limiter for the buffer travel to reduce impact on the BHO.

I keep having to bend my LRBHO wire as it jams/bends when I shoot 147gr HP. Gonna try a spikes tactical lower on my next build.

well Doug good job sharing your experience with this PPC's. I have built one of two but nowhere near your level. Have you done a 45ACP build and how did that fair? also on your buffer tube Aero makes a Standard carbine buffer tube and an Enhanced buffer tube. the issue you had was with an Enhanced buffer tube and not a Standard buffer tube.

For the LRBHO, you have to use factory Glock magazines. Also, you may have to bend the pin very slightly. But can confirm that Glock magazines work flawlessly.

The absence of those threaded screws is so fundamentally flawed! The bolt catch one especially. Good call on those Amazon 4-40 set screws.

I just had this happen to me. For the LRBHO lever, I let them know it was activating 1 round too early and I did not have to send it in, they just sent me new ones that are in route

Appreciate Ya brother, A couple of things: the set screw debacle.. i solved mine with an Aero field repair kit instead, which includes 2 pieces plus about every spare spring for the parts bin or, in my case the space inside the magpul grip. The LRBHO... i contacted Aero for mine, and they sent me 2 free replacements, which i appreciate them for since i can not just buy spares. The flat wire spring issues in the buffer tube... what issues did you run into? Other than some fiddling to feed it in, one fit into mine pretty well. Im just curious what issue you had. I also did i stall a Forward controls stronger retainer, which i assume would have only made the issue worse, but it still worked and if not needed still gives me a bit of piece of mind being stronger. But could we get a bit more info on the issue and what you did to solve the buffer tube issue?

Great work 👍🏼

Out of curiosity, what is your home defense gun? Just curious as to which one you believe to be the most reliable. Thanks in advance

This was interesting to watch. I use Colt SMG pattern magazines in both my AR9 and my AKX-9.

Dr blowback would you recommend the sporinco blue spring?

I found that my Mercury Precision (the $54 one) bolt was not milled deep enough on the ejector side. My 9mm built on a Spikes Tactical lower with the bolt in the gun would button up and the charging handle would pull the bolt back and there was about 1/8" from the end of the bolt face to the barrel causing the firing pin to not engage the primer or extract a round loaded in the chamber. I finally noticed while placing the back pin in the gun the bolt would move back, come to find out the ejector was hitting on the bolt pushing it back. After removing some material from the channel the ejector runs down the gun will fire and extract the case from the barrel.

Legend

Aero has updated the EPC buffer to be a deadblow style now, at least the one I ordered in June 2024 is a deadblow style and shaped a little differently from older pictures I've seen. No idea when they made the switch. This is an awesome channel and website, found it AFTER building my first AR-9 and running into several issues on the functional checks and test firing. Wish I had found your information ahead of time as it would have saved me a couple hundred in parts that don't play nice together.

Hey I saw a review on ammo saying something about a shorter projectile or something on a kind of 9mm ammo and he said should be fine in hand guns but that PCC might have problems if you understand what that means can u make a video on kinds of ammo that are good/bad for ar9s????

Really enjoying the blowback9 education! I was under the impression that unramped bolts were the primary culprit of trigger slap, breaking trigger and hammer pins, and egging out the holes? I'm using ALG ACT triggers and have never experienced trigger slap.

Glad you mentioned trigger slap. I actually purchased a Enhanced PCC Hammer from Centurion Arms that costs $35 that has a docked hammer, like you described. Probably could just take a mil-spec trigger and grind it down after seeing it now, but if you don't want to deal with that, this is a decent solution.

Any experience with the Freedom Ordnance FX-9? It has a proprietary bolt and barrel.

Thanks for posting this great video series

Great video!! Thank you!!

Do you see brass on the bottom of your bolt after firing?

so just to confirm, you used a standard AR15 extractor in the Mercury AR9 bolt?

I bought a few B.A.D. Bolt Catch and found out it wouldn’t work on my Aero EPC-9 before this video was up. It is due to the hole they drill on the bolt catch that interferes with the LRBHO mechanism. Well I am gonna get JB Weld and cover that hole and hopefully it fixes the problem and still looks pretty.

Wish I watched this right before ordering my triggers. Thought AR triggers are universal and bought Geissele triggers. Installed it last night just to find out on the functions check it wouldn’t reset. Had to put the MIL-Spec trigger on for now until I get something better to replace it

Weak ammo and a strong recoil spring is a problem.

The Macon Armory deadblow (leadshot-filled) 7.5 oz buffer got rid of bolt bounce in my AR9. No movement using slow mo camera when it hits the chamber

Question for ya, i always see people recommending PCC trigger systems. With your gentle recoil system, have you had issues with non PCC triggers/pins? I'm using the Geissele SD-E triggers on my 2 AR 9mm's, with your gentle recoil buffer setup. Several k rounds with no issues yet. I'm wondering if by slowing the mechanism down with the extra weight, will help stuff live longer.

I had an issue where I thought my Aero-style LRBHO was prematurely engaging but it was actually just because there was a lump of cerakote preventing the bolt catch plunger from moving outward and pushing the bolt catch into resting state. So it was the recoil that was causing the bolt catch to rattle into "catch' position. I scratched off the cerakote and the plunger was able to move in and out normally.

U definitely need to make video annealing a Colt style ejector. I snapped mine recently and I'm currently waiting for my replacement in the mail from Spikes. If you don't get to it in time I can make the video and I'll link it in the reddit group.

I have one and run it on a NFA lower for CZ mags. I plan on polishing the feed ramp because of failure to feed issue.

Thanks for sharing the different ways to activate the LRBHO. You do a great job explaining how these systems work. Of the styles used with Glock magazines, what System do you prefer between Spikes, Areo and Foxtrot Mike?

Personally, I wouldn’t build/buy an AR-9 without a bolt hold open. I’ve had issues with Metalform mags, but all my Duramags have been flawless. Thanks for sharing your knowledge!