45ish days on the Form 1, will get it to the range tomorrow if it's not pouring rain.

Specs:
QC10 Glock small frame lower
standard trigger w/ JP Light yellow springs
MVB ARC PDW Stock
Magpul K2 grip
Gibbz Arms side charging upper
QC10 .40 bolt
QC10 7.5" .40 barrel
SLR Solo Light 7" rail & M-Lock goodies
YHM Phantom 5/8"x24 thread flash hider (I had to bore it out from .30 cal to .40 with progressively increasing drill bit size and lots of cutting fluid.
BAD Lever. (bolt assist devices are NOT compatible w/ QC10 lowers out of the box. I had to carefully dremel out a small portion of material for clearance.)
Need a red dot, for now MI flip ups will work.

I need to replace the flash hider with a custom 3 lug to fit Octane45 adapter as the can is too big to fit under the rail and there would be paper thin amount of rail material left if I opened it up.

looks great. grab a cheap TRS25 for a budget red dot.

I've been looking at doing something almost identical in DI 10mm as one of my next projects, maybe a ~6" barrel.

Darn you for the temptation - particularly when I already have plain lowers with approved Form-1s....

Nice! Just wish they made a 357SIG barrel, or 10mm.

Electronic F1?

quoting to see the pics

 

Yes, that's the only way to go these days.

I forgot to mention in the first post...The QC10 bolt has a steel weight shoved in the ass end with a 1/4" roll pin holding it in place. The ARC stock will not work with it out of the box because the buffer fits inside the rear of the bolt carrier. Look it up on you tube, its all over the place. Anyway, blow back pistol ARs need a super heavy buffer, the ARC comes with an H1 buffer. I purchased a separate H2 buffer, removed the two Wolfram weights and replaced two steel weights from the ARC stock buffer to make an H3 as the final product. We'll see how she runs tomorrow.

Any reason you went blowback over DI from Macon or RMW?  Would be softer shooting and not so weight-sensitive.

Not really, parts availability I guess. I have a Rudy AR 45 upper. Variety?

What have you done to lengthen the Buffer on the MVB?  I would assume since a 9mm bolt uses a slightly longer buffer to shorten the stroke and preventing damage to the extractor; any issues in 40S&W?

Ended using a LWRC UCIW Compact Stock and Buffer tube with a Slash's 9mm Heavy Buffer specific to this setup

I really like that stock,I'm curious to see how it worked out. Will be watching this thread

How is the QC10 40 bolt and barrel? Just saw they have them in stock again.

I didn't do anything to lengthen the buffer. Was unaware of the 9mm shorter stroke cycle either. The MVB buffer comes with 2 steel weights and 1 tungsten one. I replaced the two steel with two more tungsten from an H2 buffer so now I have an H3. No range yet, crappy weather made a mudhole range. Perhaps Sunday...

how do you like that stock?

MVB mentioned on their Facebook page a while back they they will be coming out with a 9mm buffer for the ARC so I assumed the AR15 and the 9 buffer are different lengths just like in a normal adjustable buffer tube.

Here's an image of the buffers for LWRC UCIW Ultra compact stock.  The shorter buffer is for the 223 and the longer one is for a 9mm.

What is the overall length with stock extended?

Good call on the longer buffer. I shall be watching QC10s site for that coming out.

OAL from tip of flash hider to stock extended is 25.5" and 24.5" listed on Form 1 due to flash hider being non-perm attached. I can't wait to get this thing going. Going to be kick ass. I think I'll need to get a 9mm upper...maybe a 4-5" barrel for an uber shorty....

That is a really awesome build. Keep us posted on how it performs.

What's the weight difference between the MVB ARC PDW stock and a carbine stock/receiver extension...no buffer/spring?

Finally got out to shoot this thing. First round went CLICK and did nothing, my heart sank. I think it just didn't seat all the way. Take two and it ran flawlessly for a full mag during zeroing of iron sights. Recoil was a soft thump, very manageable. No noticeable wear or adverse happenings other than the first fluke. I used some handloaded 175gr lead cast boolits that were powder coated over TiteGroup powder (I forget the exact charge, on the lower end of the spectrum). It zeroed fine with iron sights, that's all I did though. The tactical bay was full of idiots doing stupid stuff that I wanted no part of.

I saw the posts above about the longer buffer for pistol calibers and the ARC stock. In lieu of waiting, I experimented a bit. Since the ARC buffer sits inside the bolt carrier, I had to remove the carrier weight that usually would slow the blow back action. To compensate for that, as I already stated above, I installed 3 tungsten weights in the buffer to make it an H3. To compensate for the length, I re-installed the large roll pin that would normally hold the carrier weight in place, but without the weight itself. This allowed the buffer to still rest inside the carrier, but only 3/4" or so. It made rearward travel that much less and had no issues feeding and ejecting brass. Jury is still out on how durable a roll pin is against recoil, I would imagine since it is hollow that it will get smushed a bit, so a solid pin would be more beneficial, I would think. Pic to illustrate:



Anyone from MVB have thoughts on this? Peanut gallery?

Also, my bored out phantom flash hider came a hair loose. It wasn't tightened mega tight, just enough to time it perfectly. I took a screwdriver in one of the ports and wrenched it down to slightly more than timed. Not really concerned with it since I plan to get a 3 lug and Octane45 it. Too loud for my tastes.

put the spikes 9mm buffer spacer in mine and it didn't fit, so I used quarters instead of putting the  pin back in the bolt. I would say that the force of the bolt being thrown rearward would be enough to cause major damage to the pin and eventually to the rifle. I would suggest the quarters as a buffer spacer instead.  my .02

Quarters like the 25 cent coin? How do they stay in place?

I also thought about replacing the weight  but cutting off a portion of the rear end so the pin would still hold it in place, but allow the MVB buffer to still rest inside the carrier. I will probably do that since I too thought the force of cycling would weaken the roll pin. I just wanted to try out the gun, only fired 15 rounds and it worked fine for that.

You take everything out of the buffer tube and drop the quarters (yes 25¢) down inside there. The buffer spring holds them in place so they don't fall over. This modification reduces the stroke of the entire system to keep everything working properly. I doubt that roll pin will last long under full power loads.

Brilliant! How much? $1.00? $1.50?

That's the beauty of it. You can tune it by how many you put in. I would put in a buck fifty or so and see if the bolt locks back. Add or subtract until you are happy.

Or you could buy some tubing to cut as a spacer for the MVB buffer.  I would take 5 min and turn up something on the lathe.

If you start spacing things in the back, you might lose the buffer-catch function of the MVB, so the action spring would no longer be captive when you take it down.

I used 7 quarters. Then I measured thickness and cut down a spikes tactical 9mm buffer spacer to the same thickness. Mine works flawlessly and It still has last round hold open and he buffer catch to take the rifle down still works fine.

What is the length of the stock collapsed measured from the back of the receiver?

Collapsed is 4 7/8"
Open is 8 7/8"

From back of receiver.

Thank you sir.

Did you run into any issues getting the bolt to work with the side charging uppper? I noticed the QC10 bolt has no cam pin.

The QC10 bolt is blow back only. The carrier IS the bolt, not like a conventional AR that is two pieces. No cam pin; nothing cams. No issues at all either. The side charging upper comes with a specially cut cam pin for use with the side charging handle if use it on a conventional rotating bolt rifle.