I'm looking for some suggestions to get the LRBHO to be more reliable on my PSA 9mm. I'd like to get it working consistently before it ruins the BCG by almost working.

I've already sent it back once and was told it was either my mags or my bolt.

It mostly works with new generation Glock mags and on a rare occasion will work with ETS mags. Magpul mags are worthless now, though they worked fine during the first 50 rounds.  The LRBHO works the same whether I am shooting or just pulling the bolt back.

I'm running a KVP BCG, Aero upper w/o fwd assist, carbine spring and PSA 9mm steel buffer. I have about 500 rounds fired.

I'd like to get a PSAK but really want this squared away first. Thanks in advance.

I have a 9mm Palmetto lower, but not the LRBHO version. It did ship with a heavier 9mm buffer (but I did not measure how heavy) that was carbine sized. I added plastics spacers from New Frontier Armory to the buffer tube to limit buffer travel. The expedient method is to add a number of quarters inside the buffer tube to limit buffer travel. To my understanding, this has the effect of slowing down the cycling action and improves reliability.

I would also check the magazines to ensure the follower is moving up with no restrictions, and contacting the bolt hold open bar, to ensure it is in the right location to trip the hold open. Does it work if you simply hand cycle the action?

Not related to your issue, my ejector extended too far into the magazine, and caused rounds to hang up by contacting the cartridges in the magazine. I took 1/16" off with a dremel to eliminate that issue. My colt pattern lower locks back the bolt 99% of the time. Even my regular AR 223 mags slip up once in a while.

Thanks for all the info.

So far I have put ~500 rounds of 115 grain ammo (Winchester, Federal and Remington) through it with no issues (except with aluminum case ammo). It should be broken in reasonably well. I've not tried heavier ammo because I've suspected bolt speed could be an issue.

I have the KAK buffer tube and stabilizer. I did install an NFA tube spacer at the outset. PSA 9mm buffer and carbine spring. I think I can run down an adjustable buffer or at least some heavier ones to try.

The bolt would lock back intermittently when pulled back. Better with new factory Glock mags. But, if it locked back, I could pull the bolt back usually 2-4 more times and it would close. Which I did not like.

One clue I picked up from another post dealt with the clearance for the LRBHO actuator bar contacting the inside of the upper receiver. This may be part of the issue. The actuator bar, at the forward pivot has a sharp 90 degree bend. I've researched other manufacturers that use a similar idea the the actuators on their guns are rounded off.

I also noted that the actuator must be designed to cant out to help lift the bolt catch into position. If the inside surface of the upper is preventing that cant, that could be another issue.

So, before I start radiusing actuators and modifying upper receivers, I am going to see if I can find a couple of other uppers from other manufacturers to slap on to see if the lock back reliability improves when I pull back the bolt.

I'm determined to get this gun working the way it should. It's too damn much fun to shoot!

My LRBHO does not function either. About 20% w Glock mags, 0% with ETS or Magpul. Only thing I can think of is increasing the spring tension to raise the bar quicker.

Another thing you can check.....the bolt catch spring should not be as strong as a normal one. It should feel like it has less resistance than a standard one, or at least mine does. If it has less resistance the follower in the magazine should have an easier time pushing up on the metal bar that then pushes the bolt catch up to lock the bolt back.

I have a Spikes 9mm LRBHO lower and although I have only shot 150-200 rounds through it it has locked back every time using the 1 ETS mag I have.

I'd like to look at the setup that the Spike's use to see how different they are.

Mine was a little better with Glock mags than 20%, but about the same with the others. Weird thing was that it worked okay with every mag I had (new and old Glock, Magpul, ETS) for the first 50 rounds and the performance has slipped ever since.

I did some light surface polishing and it seemed to help a little. Check to see if the LRBHO actuator bar is contacting your upper, that would keep it from operating as it should.

I even picked up a KVP 7.5 oz. extended buffer and extra power carbine spring to try with hopes of slowing things down to give the catch more time to get into position but didn't get the chance to try it. I sent the lower back to PSA the other day ... I got a good feeling this time.

I have a PSA lower, PSA upper, and PSA hybrid bcg. Mine is not the LRBHO model but my bolt catch barely catches when trying to lock the bolt open.  On all my other ARs, I can push the bolt catch in with one finger to get it to catch the bolt and lock open. On this PSA 9mm, I can not push it in far enough to get it to lock. I have to grab the top of the bolt catch with two fingers and pull it out to get it to lock and even then, it barely catches.  I'm wondering if yours is the same way?  Maybe it's a problem with PSAs bolt catches?

I've got a forged PSA LRBHO lower.  I run a shockwave tube, and a Blitzkrieg hydraulic buffer and spring that comes with it.  Running an NFA modular bolt.  I just completed it and tested it with 31 round ETS mags.  Aside from firing pin issues, the bolt locked back each time the mag went empty.

My bolt catch would engage the bolt without any trouble or additional effort if I pulled the bolt back and then pushed in on the bolt catch. I've used quite a few PSA parts/receivers on AR builds and never had any issues. It's possible that you have an out of spec bolt catch or spring, though. I'd look at those parts first and if they are in spec and correct then I would contact PSA to inspect the receiver to make sure the machining of the bolt catch area was done correctly. I've not had any issues with their CS other than needing patience while on hold sometimes.

Just out of curiosity, when did you get your lower?

Sometime in the last quarter last year.  I didn't have it long before started collecting parts, and remember getting the barrel on a Christmas sale.

My LRBHO lower does not work. I bought a LRBHO upper, and it works like a charm. I'd recommend you buy a LRBHO upper if you want to ensure it locks back consistently.

I got mine together last summer.

What brands are your upper and lower?

I just ordered a Spike's Tactical Glock mag stripped lower that has LRBHO. Can I run an upper that also has the LRBHO, such as the Spartan/New Frontier Armory one, or do I need an upper without that function?

I'm certain there are more knowledgeable folks here than me, but I'm pretty sure that you run only the upper or the lower with a LRBHO function - not both together. Since you have the Spike's lower on order, I'd contact Spike's and run whatever upper they recommend because I have heard of some uppers interfering with the the LRBHO actuator bar in the lower receiver. From what I've seen though, the Spike's actuator bar sits pretty low in the lower receiver, so it may not be an issue. Still, my opinion on the LRBHO feature is that in many cases it can be finicky, things never meant to function together are being asked to do so. Using an upper and lower from the same manufacturer removes one more variable from the system which should lead to elevated reliability.

I used the PSA LRBHO lower with and Aero Precision upper without forward assist. Mostly because PSA never had the finished upper that I wanted in stock and after months of waiting, decided to assemble my own. I also didn't want a forward assist because it is non-functional weight.

No matter what though, these are fun little guns and worth the effort to get them running right.

 Thanks, that's what I was kind of thinking too. I really like the looks of the New Frontier Armory/Spartan 9 uppers, but they seem to have the LRBHO feature built in. Just from my limitied reading about them it sounds like it involves some sort of spring to accomplish the bolt hold open. I'm wondering if the spring could be removed to disable it so it would work with my Spike's lower and not interfere with the LRBHO on the lower?

That's not how these work.  Just buy an Anderson Sport upper and start building.  Lots of info in this forum covering these topics.

You can use  LRBHO upper on a LRBHO lower, you just have to remove the actuator bar from one of them(I would remove it from the upper personally) to have it work together. Will not work with both LRBHO upper and lower left in stock form.

FWIW....my Spikes LRBHO 9mm lower works perfect with my Spikes slick side upper.

Is your Spike's lower still running 100% with the LRBHO? Considering giving one a whirl.

so has anyone found a solution for a stronger springs to push up the actuator bar?  My bolt will only stay open if i pull back the ch and also hold down the bottom of the bolt release button....Mag i have is an ets mag. haven't tried it with a glock mag yet.

Sorry for such a late response to you on this, but yes, it has still been 100%.