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Page AR-15 » Rimfire and Pistol Calibers
AR Sponsor: bravocompany
Posted: 3/5/2016 12:58:48 PM EDT
I went out to test my new QC10 SBR with the 9mm MVB industries stock attached and the BFS Franklin armory trigger. I had a few problems. The upper is a matrix side charger and I kept having the spent 9mm cases somehow getting up behind the bolt. This happened several times but seemed to stop once the I ran around 40 rounds through the upper. After that I was using the binary mode and I broke the bolt catch and the buffer somehow is now stuck inside part of the tube with the springs.  I was shooting with a YHM Wraith XL when the buffer and springs were compressed into the tube. This thing scares me! It has two springs and the buffer compressed into this little tube. Any ideas on how to get it out and why this happened? I did use one SS 1" (ground to fit) washer for a short spacer but that should not have caused all this should it?  I will list spec of the rifle below:




QC10 Colt lower 9mm
MVB Industries 9mm ACR stock kit with 9mm buffer (5.3 buffer) and springs
Franklin armory BFS trigger
Cmmg Bolt (ramped and modified for BFS trigger) (weight 14.7 oz)
Matrix arms side charging upper
7.5 Wilson arms SS barrel
Striker industries bolt catch

Ammo used White box winchester 9mm and monach steel cased 9mm. The stock/buffer problem happened with the white box


I am going to contact MVB industries and show them photos later today. By the way when the rifle did work in binary mode it was awesome!!
Link Posted: 3/5/2016 2:03:00 PM EDT
[#1]
Not sure what happened, but I'm guessing no need for a spacer since the tube is already so short.  Spacers were used to take up room in longer tubes.  I'd go with a heavier buffer maybe, like 8oz or so.

I'm not an expert but stayed in a Holiday Inn Express last night.
Link Posted: 3/5/2016 2:07:52 PM EDT
[#2]
The MVB ACR stock has a proprietary buffer so 5.3 is as high as I can go. I'd love to make it heavier. I was thinking about a tungsten weight in the bolt
Link Posted: 3/5/2016 2:24:55 PM EDT
[#3]
mine did the same thing they said something out of spec and replaced springs, cup, and rear tube
Link Posted: 3/5/2016 5:07:54 PM EDT
[#4]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
mine did the same thing they said something out of spec and replaced springs, cup, and rear tube
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Were you able to get the buffer out?
Link Posted: 3/5/2016 10:42:07 PM EDT
[#5]
Link Posted: 3/6/2016 2:03:29 AM EDT
[#6]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
I am concerned about the weight of the buffer....as I have said on more than one occasion....there is NO substitute for mass in a blowback system......with insufficient mass.....destructive things start to happen.....I am not comfortable with anything less than about a 6.5 ounce buffer in a 9mm.
View Quote


Is there anything heavier than tungsten weights ( that's not radioactive) ?
I can't really do anything about adding weight to the buffer. It has two tungsten weights and a larger non removable steel weight that makes up the front of the buffer. The buffer is proprietary to MVB industries so no substitute is available. I thought about a tungsten weight in the bolt. Is that possible?
Link Posted: 3/6/2016 12:06:52 PM EDT
[#7]
Link Posted: 3/6/2016 3:43:45 PM EDT
[#8]
I Did not think about lead. The MVB 9mm buffer will take standard buffer weights but only two of them. A lead weight in the bolt would work too. In binary mode the shorter the action means the less chance of hammer follow. The BFS rocked on the ar9 before the buffer stuck. My buddy said there was a spring of 6 cases in the air during one of the "bursts". I'll know something from MVB by Monday and if they let me keep the damaged parts I'll send them your way. I'm going to try and get the buffer unstuck again later this afternoon.
Link Posted: 3/6/2016 5:31:05 PM EDT
[#9]
Man, I was just about to pull the trigger on the MVB. I'll be watching this develope.
Link Posted: 3/6/2016 9:36:37 PM EDT
[#10]
Link Posted: 3/7/2016 3:06:54 PM EDT
[#11]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
I have thought about coreing the weight on a CMMG in a lathe....and then pouring molten lead in to increase mass......will the buffer bumper come off the buffer in the MVB stock....if so molten lead may be the solution there as well......guess I need to buy one and see............but that is damn expensive to experiment with....if they replace the damaged stuff.......any chance I can talk you into sending me the brokedick stuff so I can see what we are dealing with?

I helped a local with an AR45 with one.......but as it wasn't mine....and I didn't dissect it
View Quote


I got an email from MVB industries and they want me to return the tube, buffer and springs and they will send me out new ones. I think I will call them sometime this week and see if they have any solutions to add to making the buffer heavier.  I was looking around and I think I found a source for a tungsten rod that matches the diameter of the steel weight in the back of the cmmg  bolt (.620"). What are you thoughts about using that to replace the steel weight? It would add a bit to the bolts weight and does not have the downside of lead. I think it would be a pain to drill the roll pin hole but I can cut the rod with a cut off wheel and shape the front with a grinder. Do you think pure tungsten would shatter under the conditions in the bolt or would a tungsten carbide rod be better? I was also thinking about casting a lead weight for the bolt too but tungsten would be heavier.
Link Posted: 3/8/2016 9:59:37 AM EDT
[#12]
I don't have a solution to this problem, but I will say that you should not need a spacer with MVB's 9mm buffer. It is the correct length to compensate for over-travel with their stock system. I haven't run into anything like this with mine but these pictures certainly do cause concern.
Link Posted: 3/8/2016 11:48:57 AM EDT
[#13]
Not sure if that stock requires it's own 9mm buffer, bit Spikes makes an 8oz 9mm buffer for $49.

Slash's Heavy Buffers are also nice - 8.5oz w/Wolf XP spring for $75 or 12 oz 9QT w/spring for $120.

I went el cheapo with Spikes from Aim Surplus and am happy.
Link Posted: 3/8/2016 2:05:37 PM EDT
[#14]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
I don't have a solution to this problem, but I will say that you should not need a spacer with MVB's 9mm buffer. It is the correct length to compensate for over-travel with their stock system. I haven't run into anything like this with mine but these pictures certainly do cause concern.
View Quote


I am running a BFS trigger on the lower and was trying to minimize the travel beyond the bolt catch. The one washer put it just about 1/8 inch on the back of the bolt catch. The purpose was to help speed up the action to prevent hammer follow with the BFS trigger. I had no follow so I really do not think I even need it and was about to take it out when the buffer got stuck in the tube
Link Posted: 3/8/2016 2:08:58 PM EDT
[#15]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Not sure if that stock requires it's own 9mm buffer, bit Spikes makes an 8oz 9mm buffer for $49.

Slash's Heavy Buffers are also nice - 8.5oz w/Wolf XP spring for $75 or 12 oz 9QT w/spring for $120.

I went el cheapo with Spikes from Aim Surplus and am happy.
View Quote


Its a proprietary buffer and I cant use a standard buffer with the stock. Believe me if I could I would I have a YHM 9mm buffer that really wants to go back into the build when it was a pistol
Link Posted: 3/25/2016 10:03:42 AM EDT
[#16]
Anymore updates with this MVB issue? Anyone else running this stock on an AR9 without problems? I wanna get one ASAP.
Link Posted: 3/25/2016 1:02:18 PM EDT
[#17]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Anymore updates with this MVB issue? Anyone else running this stock on an AR9 without problems? I wanna get one ASAP.
View Quote



MVB replaced the buffer, springs and tube for me. Everything is working fine now. I think it was something out of spec
Link Posted: 3/25/2016 2:11:00 PM EDT
[#18]
Rgr that. Thank you, now off to order one.
Link Posted: 3/25/2016 3:09:48 PM EDT
[#19]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Anymore updates with this MVB issue? Anyone else running this stock on an AR9 without problems? I wanna get one ASAP.
View Quote


Just found this thread. I just got my MVB 9mm stock last week and put it on and tested it for the first time this week on my 5" AR. All went well. I only shot about 50 rounds to just test it out for the first time. Worked great with my 124 grain handloads both with and without the suppressor.
Link Posted: 3/25/2016 6:57:01 PM EDT
[#20]
Sweet! Just ordered it. Now only if QC10 gets off their asses and releasees the SC upper. I'm down to my last 4 items of the build. Upper. Handguard,red dot scope and my can.

Link Posted: 3/25/2016 10:03:17 PM EDT
[#21]
Link Posted: 3/26/2016 7:04:54 PM EDT
[#22]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
.......Now only if QC10 gets off their asses and releasees the SC upper.........
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Amen!
Link Posted: 3/27/2016 2:24:34 AM EDT
[#23]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Sweet! Just ordered it. Now only if QC10 gets off their asses and releasees the SC upper. I'm down to my last 4 items of the build. Upper. Handguard,red dot scope and my can.

View Quote

Have you seen the matrix arms SC upper? I like mine so far.

I want QC10 to release that mp5 lower but they will have to release a wider upper in order to get the mp5 mags to work. Mp5 mags are a little to wide for a standard AR upper
Link Posted: 3/28/2016 9:24:37 AM EDT
[#24]
Yes, that's my alternative option to the qc10sc. Really wanted to stay all QC10 with the build but I'm beginning to feel like it ain't gonna happen.
Link Posted: 3/29/2016 10:10:53 AM EDT
[#25]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Yes, that's my alternative option to the qc10sc. Really wanted to stay all QC10 with the build but I'm beginning to feel like it ain't gonna happen.
View Quote

I emailed QC10 2 days ago about their Side charger and barrel availability. Owner emailed me back and said barrels will be available in a week. The side charger is at VLTOR and waiting on a quote to handle the order. Hopefully we will see it soon.
Link Posted: 3/29/2016 1:39:07 PM EDT
[#26]
Discussion ForumsJump to Quoted PostQuote History
Quoted:

I emailed QC10 2 days ago about their Side charger and barrel availability. Owner emailed me back and said barrels will be available in a week. The side charger is at VLTOR and waiting on a quote to handle the order. Hopefully we will see it soon.
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Quoted:
Yes, that's my alternative option to the qc10sc. Really wanted to stay all QC10 with the build but I'm beginning to feel like it ain't gonna happen.

I emailed QC10 2 days ago about their Side charger and barrel availability. Owner emailed me back and said barrels will be available in a week. The side charger is at VLTOR and waiting on a quote to handle the order. Hopefully we will see it soon.


Thanks for the update. I will buy one as soon as available to replace my noFwdAsst Aero upper on my gun.
Link Posted: 5/22/2016 9:25:21 PM EDT
[#27]
bumping this. How are these 9mm MVB versions working? any other issues?
Link Posted: 5/23/2016 4:35:44 PM EDT
[#28]

Discussion ForumsJump to Quoted PostQuote History
Quoted:


bumping this. How are these 9mm MVB versions working? any other issues?
View Quote




 
I'm also curious.  Getting ready to order either one of the MVB 9mm stocks or a UCIW with Slash buffer and spring.  
Link Posted: 5/23/2016 10:17:42 PM EDT
[#29]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
bumping this. How are these 9mm MVB versions working? any other issues?
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It's working great. MVB has great CS and fixed the problem.
Page AR-15 » Rimfire and Pistol Calibers
AR Sponsor: bravocompany
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