I found that New Frontier Armory sells uppers that have a piece of metal that trips the bolt catch, but they are currently out of stock. Does any other company sell uppers like this or is there another solution that I am overlooking? Rifle is an American Tactical 9mm.

I got impatient and just spend extra for a side charger.

It has LRBHO but costs alot more.

I subscribed to the email update and got a PSA lrbho stripped lower for 99 last week. Worth a try if your stuck waiting.

I've been lurking for a while researching this and think I might have a solution, but don't know if it would work or not.

I picked up one of these to try and add to a standard AR upper: https://newfrontierarmory.com/shop/spare-part-lrbho-hardware-kit/

Has anyone tried this before?  When I got it in the mail I used my calibrated eyeball and held it up to a couple uppers that I have and it looks like the walls are too thin and might not have any material left after machining to fit.

Any thoughts?

Made the link hot: https://newfrontierarmory.com/shop/spare-part-lrbho-hardware-kit/

If you can make it work on a standard upper that would be an awesome feat, they say that's only for use on their upper that already has that feature.

I have the PSA Forged Glock lower with LRBHO, but it only works about 40% of the time.

I'm currently experimenting on a better fix to get that % up.

same here. let me know what you end up doing to mod it. thanks!

Is there any reason why someone could not just make a new bolt release/catch that has a longer "finger" that will reach the follower? When I built mine recently, I just forewent the LRBHO since it's no big deal to me. I was looking at the lower and seems this might be a relatively easy solution; however, I'm not a gunsmith nor machinist nor metallurgist. 

LRBHO on Glock mags is on the front of the mag vice the rear like on 5.56 and Colt 9mm mags

Thanks for that, guess while I was lurking I should have read how to make a link hot


So, I did some measurements tonight and things look promising!

I measured on three different forged uppers,  a Bushmaster made around '99 (my first AR,still got it), AeroPrecision that I bought a complete upper last year, and 3rd one I don't remember the brand.

In unaltered form there wasn't enough space to fit the rod between the upper and the bolt release,  but it was VERY close and would require some clearancing. All three uppers measured at approximately 3mm thick under the bolt release so not a lot of material to play with. The rod itself measured just under 3mm.

Now the good news: I was measuring "about" 2mm between the upper and the bolt release. I say "about" because it was hard to get an accurate measurement with my micrometer based on the angle. One thing I did try was to stick the rod in between the upper and bolt release and cycle the bolt by hand. As it was the bolt felt like it was hitting the release but it didn't catch unless I held the release in farther.

At this point I'm feeling confident enough in my idea that I'm going to order a cheap upper to do some work on.  Unfortunately I can't post pics to make everyone happy...

Part 2: (stupid 2000 character limit)

If anyone has an NFA upper with the lrbho and can post a pic of the bottom of the upper it would be helpful

I will post pics here within the hour. Do you just want a pic of the bottom from an underneath view?

Eta:
Attached File

Attached File

Attached File

Please someone try this. I too was curious if this conversion was possible.

VERY interesting! Looks like the same thickness under the bolt release.  I'm most surprised that the front isn't a notch for the rod. Looks like it will take less machining than I originally thought. Only concern is how the thickens where the cover mounts....

I bought an Anderson upper for $45, if it works, awesome,  if not in not going to be out a bunch of money. I'll update when it gets in and I've done some work.

Any updates on this project?

I stopped by there shop since I had an hour to waste yesterday, they had there stripped billet uppers and one of these vaporware on display but none for sale.  It appeared to me that there billet upper and lrbho upper are the same minus the parts mentioned above and 1 rod hole and 3 mounting block holes drilled and tapped.  I tried to buy one of the uppers but they would not sell since demo only.  From my quick look it appeared to me that only there billet upper would work, not a standard forged.  But I would still like to buy one to check side by side against my vltor billet.  


Any one recognize who produces there billet uppers to try and source from the manufacturer?

The New Frontier is the only 100% reliable Glock mag set up there is. It requires both their upper and lower to work. They also make these uppers and lowers for Runner Runner Guns and mark them with a Runner Runner Logo. Neither appear to currently have the upper but Runner Runner lists the lower as in stock.

When I built mine, Runner Runner had lowers but not uppers and NFA had uppers but not lowers. So mine is mixed logos but runs like a sewing machine.

I run a Black Creek Precision lower and the LRBHO has worked every time. I use a standard M4 upper with it. No special mods.

FYI if anybody is feeling brave and has money to burn  check out rainier arms 9mm upper it has a flat portion where the NFA LRBO parts might be able to bolt to  
rainier arms 9mm upper

Ok, I got an upper in and did some more checking...unfortunately bad news.  The height of the spot the rod needs to go is too short on a forged upper (went back and looked at my others again and missed that).  It won't work on a forged upper.  I don't know about any of the billet uppers.

Now for some good news!  I found a few places with uppers in stock:
http://www.wcarmory.com/new-frontier-side-charging-ar-9-stripped-billet-upper-with-lrbho.htm      (pretty quick delivery time, about week and half)
https://www.wolfpackarmoryusa.com/product-page/cerakoted-ar9-upper-lower-set                        (80% lower/upper pair, and they can do custom engraving if you want to SBR)

Haven't really had any free time to look into retrofitting due to work, but I did wonder if just a few simple slots, a small allen wrench, and a low profile button head screw as a hold down would work pretty well. I set a 1.5mm allen under the bolt catch and it looks like about 10 minutes of simple slotting and bending the wrench would be all it takes.

Attached File

Forgot to add:
If you're going to try bending an Allen wrench, anneal it first, then heat treat again afterwards or it's just going to be an exercise in futility

i started the same project two years ago but got sidetracked.

milled the slots in the lower but never made the bar.

before i butchered it...

Attached File


current pics tomoro, maybe...