Got mine Friday and had a chance to really look at it this weekend - gotta say I'm not impressed.


So far both barrels I have tried have a ton of slop when inserted. I started with the intended barrel, a Kaw Valley 8.5" 9mm, and thought that it may just be a tolerance stacking issue so I tried an extra BA 7.5" 5.56 and had the same experience - both barrels visibly rock back and forth when fully inserted. When I say rock back and forth, I mean like an audible "rattle". On an 8.5" barrel, I get approx. 1/8" side to side movement at the end of the barrel when full inserted.


Not only does the face not appear to be true, the inside diameter is too large, or at least larger than any other receivers I have (or have ever used). I tried those exact same barrels in both a Spikes and an Aero Precision upper and had a nice tight fit with no discernible slop. I have experienced some barrel/upper combinations that were slightly tighter or looser, but I have never seen this kind of play. I feel pretty comfortable that it's the NFA LRBHO upper that is the problem in this equation. The barrel recess is off center in the upper but it appears to be a minor offset so I'm not sure if that is a coincidence or possible cause. Not happy.




There is also an issue with the rail height. It appears that the receiver rail is about 0.7mm too low as it does not match heights with any rail I have. Looking at the individual rail segments compared against other rails, it's readily apparent that they are not the same size/height as a standard rail. I ordered one of the inexpensive Matrix Arms "Foxtrot" rails just check one out and my first thought was that maybe that rail was the problem. Nope - used the same process as with the barrels. The MA rail mates perfectly with both the Spikes and AP upper. I then tried a couple other rails (YHM Diamond and MI Gen2 SSG) and had the exact same issue with the NFA upper - rail heights don't match (NFA upper shorter than each) and a much different rail profile.

YHM:




Matrix Arms:





It may not affect function/reliability, but it's sloppy, especially since I have never see this issue with any other rail/upper combination (Spikes, BCM, AP, CMMG, and Bushmaster uppers plus Geissele, MI, YHM, and CMMG rails - heck even the UTG Pro rails are the correct height). I'm not a master machinist by any stretch, but I've built or reconfigured a decent number of rifles and this was an unexpected disappointment.


The finish is odd, a semi-gloss anodizing that looks almost painted on. The glossy upper finish in these pics is dry - no oil/grease applied. This is not that big a deal to me as I was planning on refinishing everything anyway but I thought I would throw it out there. Nothing at all like the "matching" NFA lower (RunnerRunner) which has a more traditional matte anodizing. It's not even close.


Machining looks decent with minimal tool marks, but there are a couple of minor edge dings (before anodizing) that make me think they are churning these out as fast as possible and maybe letting some stuff slide on the QC side. Not familiar enough with NFA to say if this is normal or not.

The takedown pin holes are off-center in the lugs, but that may not be an issue. I've seen it before but never to this extent.






Sorry I can't comment on the LRBHO functionality but I'm not really excited about building anything with this upper. Maybe I just got a bad piece, but given all the delays, I'm surprised to see these issues. I could live with the gloss finish and maybe even the rail height issue, but the barrel slop is one bridge too far. I could try and true up the face and maybe experiment with the whole "loc-tite the barrel" thing but I'm not willing to go through all that for a brand new upper. Am I being unreasonable?


TL:DR - I'm sorry I waited for this and will likely send it back and just forego LRBHO.


Is anyone else seeing these issues or did I just get an out of spec upper? I will contact NFA this afternoon, but if these are common issues, I'll pass and just go with a standard receiver. If I'm crazy and being too picky, just say the word and I'll reset my expectations.

Thanks and any input is appreciated.

That upper is out of spec.  Send that POS back.

I will need to double check mine but I don't remember any of the issues that you are seeing.

I will note that the machining on mine around the ejection port is a little wavy but shouldn't affect function.  Also I have the Runner Runner Guns lower and the finish matches between the NFA LRBHO upper and the lower.  

If it were me, I would contact NFA and see what they can do.  Should have come right to begin with.  Maybe they got swamped by demand and some stuff made it out that shouldn't have.

Given the delays on those uppers, they're probably shipping everything they can now that they think they have a LRBHO that works.  Quite a bit of pent up demand for those uppers.

My barrel fitment was good but the rail height difference is there, along with some sweet blems. I guess there is a reason why they cost a lot less than competitors.





Matching NFA/Joe Bob lower

Yeah, that gouge would not make me happy at all!  :(

Wow I'm glad I didn't jump on the order bandwagon when they came out.  Also kind of glad I'm not worrying about LRBHO with mine.  

Newbie with a newbie question,what manufacturer is LRBHO?

Edit***
Disregard, Last Round Bolt Hold Open... Kind of like my Yugo BHO for my AK... What manufacturer is NFA?

Part of your rail problem is that the barrel is mounted higher in the upper making your handguard higher as well. That doesn't make it ok but just pointing out that the rail may actually be standard height after all.

Mine arrived last week and I'm pretty happy with it.  It's not a LaRue.   It's a $49 upper that has unique features commanding a $140 price tag.  I got what I expected and got the LRBHO to seem to be working great through handcycling.  I had to remove the wire and increase the downward angle of the hook end a bit.  Down to where it is almost touching the lip of the inserted mag.  Gets the hook end real deep in there so the mag follower pushes it up far to fully engage the bolt catch with the bolt.

Finished was a dry dull grey out of the box, but after soaking it down with oil and an overnight soak up into the coating or anodizing or whatever that is, the color and texture seems to match the NFA lower pretty well.

Upper to receiver fit has a little rattle in it.  No rock solid lock up like I get lucky with sometimes.

I've hand cycled rounds through it and it feeds and ejects great too.

I did notice a bit of barrel to receiver slop with an NFA bbl.  Also, some side to side with the index pin.  But nothing worse than I have seen in some of my other builds that shoot fine.   I'm just using a old school round free float forearm tube so rail height is a non issue right now.

Can't wait to shoot it.

Thanks for the feedback, folks - got caught up at work yesterday so I couldn't contact NFA but will try today and will update when I can. I don't expect LaRue quality, but for a billet upper costing $130, I expect it to be at least dimensionally correct.




Thanks for jumping in, but that's not correct. The rail is mounted directly to the receiver, not the barrel, so the barrel being offset slightly high will not impact the top rail height. It wouldn't matter how offset the barrel was (in any direction) because the barrel nut is screwed to the external receiver threads.




New Frontier Arms

Sorry for all the acronyms...

man, I feel your pain. Basically very similar to my experience. I didn't notice the barrel fitment issue like yours but everything else is spot on, and what worried me is the amount of rearward slack in it. it's just extremely sloppy and seemingly out of spec all over the place.

How difficult would it be to reproduce the set up on a standard receiver?  If it's an additional hole with a particular type of wire, it seems fairly elementary, provided there are specs or measurements to put the hole in correct place.

 
Been wondering that myself.


Could one of you guys with one of these uppers snap some pics of the inside?

How many business models are you going to sink this week?    Still curious if their set up will work on other non-NFA pattern Glock lowers.  One DDLES fellas has reported that after he tweaked it it worked.

I don't have the upper handy right now for pics.   And you'd have to pull the plate off again to really see how it's designed and I don't feel like doing that again.  

It's just a coat hanger wire (maybe slightly skinnier and made of spring steel) that lays against the outside of the upper and is held against the side with the screw on plate that is channeled so the wire can move freely.

The front of the wire has a hook end and the back end has an L shape.  Sort of like this.

/\__________|

Looking from the front would be like this:

/\|

There is a slot in the receiver where the hook end enters the receiver, which places the crook of the hook above the mag lip, then the end of it sticks down in the mag, waiting for the follower to come up and push it upwards.   The slide stop step on the follower contacts the end of the hook.  The hook end is shaved down to a point, so it's skinny enough to fit down in the mag and only make contact on the mag follower step.

The L part sits behind the top of the bolt catch lever.   When the hook end goes up, it rotates the wire, which pushes the end of the L out away from the receiver, and this pushes the top of the bolt catch out to engage the bolt.


Pretty simple, but ingenious.

 
I thought that was the case.....now I just need to buy a mill so I can make my own MUAH HAH HAH HAH

I'm guessing these are the same uppers that runnerrunnerguns.com sells? Made by NFA? It doesn't say on their site.

Runnerrunner LRBHO Upper

I just ordered a lower from them today, and figured I would order a matching upper. Bad idea?

Same stuff different roll mark.

I watched this thread with interest but couldn't contribute because I hadn't shot my setup yet.  I made it to the range this weekend and thought I'd share my results.

Here's my setup:
NFA Glock lower
NFA LRBHO upper from JoeBob's
NFA 8" barrel
NFA 9mm bolt (not modular)
MI 7.25" handguard
ETS mags/Glock 26 mags

This thing is SWEET!!!!!  LRBHO worked every time.  No misfeeds or malfunctions.  Functioned flawlessly every time for 200+ rounds.  Aside from my MP5, I'd say this thing is my new favorite gun.  Nothing like mowing thru a plate rack at 25 yds with an AR based weapon.

Good to hear.  +1/-1 on the LRBHO now.