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Posted: 8/2/2016 2:11:02 PM EDT
Anybody run a LaRue MBT in a 9mm AR? I just put one in my QC10 GSF and it function checks just fine in the lower but the hammer follows the bolt forward when holding the trigger back with the upper on. It resets fine with the bolt if the trigger is not held back. This a CMMG ramper bolt with a glock cut. Any suggestions or is this trigger just a no go in my application?
Link Posted: 8/2/2016 2:33:20 PM EDT
[#1]
What buffer system are you using?  Any chance it needs a longer stroke to push the hammer lower so it will engage the disconnector while the trigger is held back?
Link Posted: 8/2/2016 3:03:38 PM EDT
[#2]
This is a pistol buffer tube with a standard spring and a spikes 9mm buffer. It's not locking back with me using the charging handle to cycle it when trigger is held. Using the charging handle without holding the trigger it works fine.
Link Posted: 8/2/2016 3:06:28 PM EDT
[#3]

Spikes 9x buffer?  Try cycling it without the buffer (or with a standard length buffer) and see if the disco catches.


It's possible the hammer is never getting pushed low enough because the long buffer keeps the carrier from cycling far enough to the rear.  If this is the case you could swap to a traditional length 9mm buffer or swap FCG's.


Link Posted: 8/3/2016 10:04:35 AM EDT
[#4]
Thanks for your suggestions jaqufrost. Yes it's the Spikes 9x. It's working now. I tried a standard buffer and that worked but not consistently at first. I cycled it quite a few times testing it and it finally started resetting 100%. I swapped the 9x back in and that is working now also, I just noticed I really need to make sure I pull back hard on the charging handle to get it to work. There was a big blob of grease on the disconnector that is now dispersed with all the cycling so maybe that was causing some issues or it just needed to be worked in a little for this application? Either way thanks again for the help.
Link Posted: 8/3/2016 10:53:48 AM EDT
[#5]
I tried a few lighter triggers in my 9mm and had issues with doubling and tripling. Maybe it was me and an uncontrolled bump fire.  

I prefer a heavier trigger because of that.  I use the ALG enhanced trigger group.  Clean break, smooth, consistent.  Somewhere between 5-8lbs but I don't recall if I actually measured it.

I did put an MBT in my .45ACP SBR, but I haven't fired it yet.  It is a nice trigger.
Link Posted: 8/4/2016 12:38:45 AM EDT
[#6]
I had an MBT in my QC10 lower, QC10 bolt, slash's heavy buffer setup. The trigger wouldn't reset once every 20-30 rounds, then finally fired a 4 round burst at the indoor range which got me some funny looks. I swapped it for a milspec trigger in one of my rifles for now. I'll be trying an SSA-E in it as funds allow.

It was disappointing. I absolutely love the MBT trigger.
Link Posted: 8/4/2016 1:44:20 PM EDT
[#7]
Thanks for the insight. I haven't gotten to the range yet to fire it, I've only been testing it prior to shooting it knowing not all triggers work with 9mm. At the same time I posted this I did contact LaRue for their input. They want me to take detailed pictures and send them in so they can look at them. I'll be doing that and updating this post if needed.
Link Posted: 8/4/2016 8:14:08 PM EDT
[#8]
Link Posted: 8/5/2016 1:41:19 AM EDT
[#9]
I run a MBT in my QC10 small frame glock and other than the occasional bump its great.
Link Posted: 8/5/2016 1:45:56 AM EDT
[#10]
I put an MBT in my 9mm, and it kept following the hammer.  Then it doubled.   Then it was out.  

I have a JP spring that I should try with it now, but the POF that I have in there works great.
Link Posted: 8/5/2016 8:59:23 PM EDT
[#11]
I have a DDLES lower, QC10  upper, JP 9mm bolt and JP silent captured spring buffer with an MBT and I've had issues with the hammer resetting properly.  Ran it for maybe 50 rounds on my initial range trip with 147gr Speer Lawman ammo.  Decided to try another trigger, so I just received the ALG trigger and JP trigger springs to try.  Will report back on the results but it looks like the MBT won't work with my 9mm AR setup either.  It's not a problem since I can use the MBT in another AR build, but I will really miss the LaRue trigger feel/break.
Link Posted: 8/5/2016 9:30:20 PM EDT
[#12]
SD3G's have also had issues. I need to pick up my own 9mm setup so I can diagnose the problems.
Link Posted: 8/11/2016 3:22:41 PM EDT
[#13]
Link Posted: 9/5/2016 9:06:59 PM EDT
[#14]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
I have a DDLES lower, QC10  upper, JP 9mm bolt and JP silent captured spring buffer with an MBT and I've had issues with the hammer resetting properly.  Ran it for maybe 50 rounds on my initial range trip with 147gr Speer Lawman ammo.  Decided to try another trigger, so I just received the ALG trigger and JP trigger springs to try.  Will report back on the results but it looks like the MBT won't work with my 9mm AR setup either.  It's not a problem since I can use the MBT in another AR build, but I will really miss the LaRue trigger feel/break.
View Quote


Installed the ALG trigger & JP trigger springs and it runs fine now (150+ rounds) with no trigger reset issues.  I really hated to pull that MBT out, but I'll just use it in another build since I have 2 spare LaRue barrels waiting for use.
Link Posted: 9/6/2016 3:17:04 AM EDT
[#15]
I have one on order. I have a 5", 3lugged upper that stays suppressed, 100% reliable with a 5.6oz buffer, CMMG bolt and G2S trigger. Building a QC10 lower for it, when the ATF gets off its ass and approves the SBRing I'll put it together with an MBT I just ordered. The rifle is gonna be kick-ass, lets see how the trigger fits in in this equation.
Link Posted: 9/29/2016 7:33:08 AM EDT
[#16]
Any movement on this?

Gonna try a POF single stage in the meantime
Link Posted: 9/29/2016 11:14:54 AM EDT
[#17]
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Quoted:
Any movement on this?

Gonna try a POF single stage in the meantime
View Quote


POF is 100%. Can't speak for the MBT though
Link Posted: 9/29/2016 2:11:58 PM EDT
[#18]
Nope sent pictures as requested to Larue and never heard anything back. Others that posted they were going to test never came back with results. It still hasn't been resolved for me so the Rock River 2 stage went back in and the MBT is sitting on the self.
Link Posted: 9/30/2016 3:01:17 PM EDT
[#19]
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Quoted:
Nope sent pictures as requested to Larue and never heard anything back. Others that posted they were going to test never came back with results. It still hasn't been resolved for me so the Rock River 2 stage went back in and the MBT is sitting on the self.
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So the Rock River 2 stage triggers work? Assuming it's the 4.5# and not the 3.5#?
Link Posted: 10/2/2016 8:52:37 PM EDT
[#20]
Discussion ForumsJump to Quoted PostQuote History
Quoted:


So the Rock River 2 stage triggers work? Assuming it's the 4.5# and not the 3.5#?
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Quoted:
Quoted:
Nope sent pictures as requested to Larue and never heard anything back. Others that posted they were going to test never came back with results. It still hasn't been resolved for me so the Rock River 2 stage went back in and the MBT is sitting on the self.


So the Rock River 2 stage triggers work? Assuming it's the 4.5# and not the 3.5#?


Not recommended or warranteed for blowback ARs.
Link Posted: 10/3/2016 11:00:37 AM EDT
[#21]
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Quoted:


Not recommended or warranteed for blowback ARs.
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Quoted:
Quoted:
Quoted:
Nope sent pictures as requested to Larue and never heard anything back. Others that posted they were going to test never came back with results. It still hasn't been resolved for me so the Rock River 2 stage went back in and the MBT is sitting on the self.


So the Rock River 2 stage triggers work? Assuming it's the 4.5# and not the 3.5#?


Not recommended or warranteed for blowback ARs.


Actually, I messaged RRA on here with concerns regarding this because I wanted to try one out in either a 458 SOCOM or my 9mm and Steve said it will stand up to either. He said they redesigned the bolt in 2014 and it has resolved those issues with the 9mm rifles. I assume the issue was coming from people using them with non ramped bolts.
Link Posted: 10/3/2016 6:35:44 PM EDT
[#22]
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Quoted:


POF is 100%. Can't speak for the MBT though
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Quoted:
Quoted:
Any movement on this?

Gonna try a POF single stage in the meantime


POF is 100%. Can't speak for the MBT though



I love the POF in my  9mm's.   MBT's in the other.   ML can tell you based upon my orders that pretty much all my non-9mm AR's have them now.    

The MBT in my 9mm doubled more than once and did not reset correctly.
Link Posted: 10/3/2016 7:41:14 PM EDT
[#23]
Had the same issue with the SD3G. The hammer face was just short enough to not properly engage the ramped bolt as it goes back. Usually during rapid fires, solved the problem by welding a bead on bolt to give it just enough height to have positive contact with hammer face.....someone on this site did it before me and posted pics.

Specs: 9mm
QC10 upper/lower
QC 10 ramped bolt - glock cut
MVB  9mm ARC stock
Giselle SD3G - trigger works 100%. Flawless no matter how fast I run it.
Link Posted: 10/17/2016 4:04:43 PM EDT
[#24]
My PSA 9mm build won’t run with a MBT either.

PSA upper/lower/hybrid bolt.
Spikes carbine buffer tube and spring.
Spikes 9x buffer.

It doesn’t double; just doesn’t reset the trigger.

Sucks… I love the MBT trigger.
I have them in both my and my wife's standard 5.56 ARs and have two more on the way to stash for future builds.

PS: An ALG ACT trigger is working fine and what I have currently installed.
And with a JP reduce power spring set it turns into a pretty decent trigger.
Link Posted: 10/17/2016 4:15:26 PM EDT
[#25]
I have run one in my AR9mm since the trigger came out (I prefer the old coloring too, btw).  Recently it started to occasionally light strike, then the last 3-400 rounds it started to double & triple.  Carbine has somewhere around 4-6,000 rounds down the pipe.







I am in the process of switching triggers to eliminate the buffer system since I already tried several of my other lowers in this upper.










I like the trigger but if it doubles in a standard 5.56 upper, I will be very disappointed.



















Colt Pattern:


Upper:  CMMG 8" bbl, CMMG bolt



Lower:  CMMG dedicated, JP buffer, MBT trigger



 










Note:  I could not get the SD-3G trigger to work at all, the reset just wasn't timed right.  The SSA works fine as does the RRA NM.


 
Link Posted: 10/17/2016 5:01:37 PM EDT
[#26]
Link Posted: 10/21/2016 11:30:46 PM EDT
[#28]

Discussion ForumsJump to Quoted PostQuote History
Quoted:
^^^



Before you switch, for grins, I'm interested in sending you new springs.



ML
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Quoted:



Quoted:

I have run one in my AR9mm since the trigger came out (I prefer the old coloring too, btw).  Recently it started to occasionally light strike, then the last 3-400 rounds it started to double & triple.  Carbine has somewhere around 4-6,000 rounds down the pipe.



I am in the process of switching triggers to eliminate the buffer system since I already tried several of my other lowers in this upper.





I like the trigger but if it doubles in a standard 5.56 upper, I will be very disappointed.
Colt Pattern:

Upper:  CMMG 8" bbl, CMMG bolt

Lower:  CMMG dedicated, JP buffer, MBT trigger

 
Note:  I could not get the SD-3G trigger to work at all, the reset just wasn't timed right.  The SSA works fine as does the RRA NM.

 

^^^



Before you switch, for grins, I'm interested in sending you new springs.



ML




 
Email sent.
Link Posted: 11/16/2016 10:29:38 AM EDT
[#29]
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Quoted:


Standing by ...
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Quoted:
Quoted:
I have one (Larue Trigger) on my desk that is getting checked with a 9mm upper.....hopefully this week to see what is required to make it run and reset.......


Standing by ...
Yea.... me too. It's MY trigger and I REALLY want to use it!

Wink,wink,nudge,nudge.....
Link Posted: 11/16/2016 11:30:21 PM EDT
[#30]
Mine doubled a few times when it was in pistol config, but now that the NFA fairy brought my stamp it runs like a champ.  Over 300 trouble free rounds.  MBT, QC10 Bolt,
QC10 lower, PSA upper receiver.
Link Posted: 11/19/2016 7:28:51 PM EDT
[#31]
I did a static test pulling the charging handle back until I felt and heard the trigger reset.

Comparing an ALG ACT trigger to the MBT: The MBT trigger required a good half an inch more rearward bolt travel before it reset.

Not sure what to make of that... maybe we need to create more rearward bolt travel? Cut off a coil of the buffer spring? or?
Link Posted: 11/21/2016 3:34:59 PM EDT
[#32]
I finished my 9MM NFA Receiver build last weekend. My MBT would only reset if you pulled the trigger, released the trigger and then cycled the bolt. If you pulled it, cycled the bolt then released the hammer would follow the BCG. I don't have a glock-cut unramped bolt, so I couldn't do a before/after check.

This is with a NFA ramped bolt. I didn't test fire it since it wasn't passing the function check and I didn't want a runaway situation.

So I swapped to a Geissele S-3G, and had the same issue.

So I bummed a ALG-ACT from a friend, and it works. Turns out I could have saved some time browsing the forum here first.

At least I put the MBT into my 300 SBR.
Link Posted: 11/21/2016 8:30:55 PM EDT
[#33]
This is the configuration that's working for me.  Black Creek Precision, Colt pattern, dedicated 9MM forged lower.  RRA upper receiver.  RRA factory ramped bolt.  ADCO 5" barrel.  MVB ARC 9MM PDW stock.  LaRue MBT-2S trigger.  Metalform 32 round magazines.  I had a few failures to reset in early testing with the MBT trigger but I'm convinced it was because I was being too easy on the trigger (bump fire / out ran the bolt).  The gun always chambered the next round and when I made a conscious effort to hold the trigger firmly back after each shot there were no issues.  I haven't tried it yet but I think the heavier trigger spring that came with the MBT might be the better choice for this build. So far I've tested with Federal HST 147Gr, Speer Gold Dot 147Gr, Remington Golden Saber 147Gr and some Winchester and Blazer 115 Gr FMJ.  With the MVB stock, bolt travel ends about 1/8" inch behind the bolt stop.  This gun passes function checks, has never doubled, failed to feed, failed to eject or failed to lock open on an empty magazine.  I'm also planning on trying the Franklin Armory BFS trigger when it arrives.  I'm loving this gun and once the form 4 clears for the suppressor I'm planning on this being my primary home defense gun.
Link Posted: 11/23/2016 2:29:01 PM EDT
[#34]
I have had the Larue MBT in my suppressed 9mm SBR for several months now.  Mine is a New Frontier 9mm lower for Glock mags.  I haven't had a single issue.  Cycles 100% of the time without issue.  I really thought the MBT would have issues with the heavier and more abusive bolt.  I have run it without issue on 3 different bolts.  The NFA standard 9mm and the NFA modular 9mm as well as the JP Enterprises Enhanced 9mm bolt.  I haven't had a single issue.  

Pic is before the trigger upgrade and before the SBR stamp came back.
Link Posted: 11/23/2016 5:05:48 PM EDT
[#35]
I need a flat MBT sofa king bad.  Especially if it works with my 9mm bolt.

Link Posted: 11/23/2016 6:18:32 PM EDT
[#36]
I wonder how much of this is bolt related. My PSA dedicated Colt build doesn't work with either the PSA hybrid bolt or KVP.

Unfortunately I can't afford to keep buying bolts until I get one that works... assuming that is even the problem in the first place.

Link Posted: 11/26/2016 1:46:59 AM EDT
[#37]
Another thought:

The recent (although still provisional) update to the IDPA rule book defines a new IDPA division for PCC (pistol caliber carbine).
This follows on the heels of USPSA defining (also provisional) a similar division for PCC.
Although the rules differ that doesn't change the fact that the two major action pistol sanctioning organizations in the USA have welcomed the PCC concept.

Given that level of interest combined with the general increase in interest in 9mm AR I would hope that such AR15 community stalwarts such as Larue might become more active in supporting the PCC concept.
I would think there is money to be made there, eh?

I know that Mark Larue posted in this thread earlier and that is a very good sign! I hope that his investigation into this issue bears fruit.

Hopefully between him and Rudy from Macon who is supposed to have good "9mm AR karma" they might figure out what's going on here.

Too much to hope for? I personally would love to have a reliable 9mm AR setup with a Larue MBT.
Link Posted: 11/26/2016 10:43:07 AM EDT
[#38]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Another thought:

The recent (although still provisional) update to the IDPA rule book defines a new IDPA division for PCC (pistol caliber carbine).
This follows on the heels of USPSA defining (also provisional) a similar division for PCC.
Although the rules differ that doesn't change the fact that the two major action pistol sanctioning organizations in the USA have welcomed the PCC concept.

Too much to hope for? I personally would love to have a reliable 9mm AR setup with a Larue MBT.
View Quote


I just shot the PCC I mentioned above in our 'outlaw' pistol match as a PCC. I would have liked to have run the MBT, but don't have the budget to buy 3 or 4 glock cut bolts to experiment with. (Well, I do, but I'd take that 600 and go buy a 9mm tavor at that point).

I had a few light strikes with the ALG which didn't help a few stages, not sure the MBT would have made a difference, but I much prefer it.
Link Posted: 11/26/2016 11:53:10 AM EDT
[#39]
Discussion ForumsJump to Quoted PostQuote History

... I just shot the PCC I mentioned above in our 'outlaw' pistol match as a PCC. I would have liked to have run the MBT, but don't have the budget to buy 3 or 4 glock cut bolts to experiment with. (Well, I do, but I'd take that 600 and go buy a 9mm tavor at that point).

I had a few light strikes with the ALG which didn't help a few stages, not sure the MBT would have made a difference, but I much prefer it.
View Quote


That is a little troubling as I was hoping the ALG trigger was going to be good enough. So far I haven't had any issues but I don't have all that many rounds of testing done yet; maybe 150 max.

Most of my 9mm range time has been spend trying to get the MBT or the Hiperfire 243G to run. I thought the 243G was the answer for the first 50 rounds and then it started failing to reset also. Frustrating.

Ulfhednar_42: Do you have a standard spring kit in your ALG or one of the reduced power spring sets?
Link Posted: 11/26/2016 1:13:59 PM EDT
[#40]
Link Posted: 11/26/2016 4:09:13 PM EDT
[#41]
Discussion ForumsJump to Quoted PostQuote History
Quoted:

I know that Mark Larue posted in this thread earlier and that is a very good sign! I hope that his investigation into this issue bears fruit.

Hopefully between him and Rudy from Macon who is supposed to have good "9mm AR karma" they might figure out what's going on here.

Too much to hope for? I personally would love to have a reliable 9mm AR setup with a Larue MBT.
View Quote


Rudy has had my MBT trigger for testing for about 5 months now. I figure if I keep bugging him he'll either get around to actually testing it or send it back so I can put it in another rifle.... the standard GI trigger works fine with his bolt, neither the MBT or SSA work however.....
Link Posted: 11/26/2016 6:50:48 PM EDT
[#42]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Ulfhednar_42: Do you have a standard spring kit in your ALG or one of the reduced power spring sets?
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It's the spring that was installed in the package.
Link Posted: 11/27/2016 1:00:38 AM EDT
[#43]
Discussion ForumsJump to Quoted PostQuote History

Rudy has had my MBT trigger for testing for about 5 months now. I figure if I keep bugging him he'll either get around to actually testing it or send it back so I can put it in another rifle.... the standard GI trigger works fine with his bolt, neither the MBT or SSA work however.....
View Quote


ouch, that was not what I was hoping to hear. I had heard he was the goto guy for 9mm AR issues.
Link Posted: 11/27/2016 1:35:20 AM EDT
[#44]
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Quoted:


ouch, that was not what I was hoping to hear. I had heard he was the goto guy for 9mm AR issues.
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Quoted:

Rudy has had my MBT trigger for testing for about 5 months now. I figure if I keep bugging him he'll either get around to actually testing it or send it back so I can put it in another rifle.... the standard GI trigger works fine with his bolt, neither the MBT or SSA work however.....


ouch, that was not what I was hoping to hear. I had heard he was the goto guy for 9mm AR issues.



He is... but Rudy has a lot of irons in the fire.
Link Posted: 11/27/2016 4:59:08 AM EDT
[#45]
Geissele G2S has worked perfectly with two different CMMG bolts, im two different upper, suppressed, unsuppressed, 5" barrel and 10.5" barrel. That's my test sample.
Link Posted: 11/27/2016 7:13:50 PM EDT
[#46]
So far my MBT has worked in my QC10/Macon Armory dedicated 9mm Rudy built for me. Its a recent manufacture MBT if it matters.
Link Posted: 11/27/2016 9:08:38 PM EDT
[#47]
Link Posted: 12/1/2016 9:10:07 PM EDT
[#48]
Link Posted: 12/1/2016 11:18:34 PM EDT
[#49]
Link Posted: 12/2/2016 5:30:34 PM EDT
[#50]
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Quoted:



AWESOME !! Thanks to Both you and LaRue   !!!
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Trigger is on the way back by priority mail.....I already have MBT hammer/trigger  sets in my office from the good folks at Larue Tactical.....and as soon as I finish up the changes I am making.....testing will begin.......once I have a minimum of 1000 rounds down range....we hope to put the solution in production.....and get it up on the website for purchase.



AWESOME !! Thanks to Both you and LaRue   !!!


Ditto - if there's a working MBT solution, I'll gladly send some money to Georgia to get one for my NFA-Glock mag lower.
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