Blow Back Uppers

[HMC710]

For all you blow back fans out there, if you have been following what started as the 22 TCM craze, I've been doing a lot of blow back work. From the posts above, the Tok is a much more powerful round than the 9mm and was doubly harsh operating. From the work I've been doing starting with the 22 TCM and cutting it down to fit in a 9mm Uzi / Colt mag, my goal has been to see what we could do to smooth out the blow backs and safely get some more powerful rounds running in all the uppers out there. To get to that point I mapped out the forces in the AR. Negative forces are from firing the round and positive forces are the opposite reactions to that. This led us to work on what I called Delay Devices. Something that would mechanically add force with out adding weight. Surfing the web shows all kinds of ways to do this but my main goal was to find something that worked within the AR platform. I've been testing Delay Device #1 for a while with some success and was working on DD#2 when I changed gears..............

[HMC710]

My latest blowback is a 10" Tokarev AR pistol. Running old surplus it stinks and smokes but we are getting it tuned in. Got a few bolt over jams so going to stretch out the mag spring and try again. My notes say we hit 1680 fps, but i thought it was over 1800..... ill verify that tomorrow because if its not over 1800, the 30 Slug'r kicked its ass today.

[HMC710]

Verified the tok velocity today and got 1637 - 1705 from the 10" barrel. Looking back through old notes, thats the range ive been getting. So that confirms the new 30 slug'r will out perform it and use stock 9mm parts.
I made some adjustments on the recoil system and did a couple of mag dumps and the new setup is pretty nice. Ive got some tuning yet to do but i think its going to be a winner.

[HMC710]

Got back Sunday night in time to watch Denver give some football lessons to Carolina, what a game! Getting things unpacked today and getting shop cleaned up. Since I've been on the road the shop has become more of a storage bin than a shop so its time to reinforce the expectations. I had some interesting tests last week on both blow back uppers so we are taking that info and translating it into hard parts as we move forward on these units. Bro has a big gun show at the end of the month and invited me to come with so I want to have all my ducks in a row for that. I just ordered some more barrel blanks so that should stock us up in the .30 cal, 9mm, and .22 cal supply. Keep an eye on this folks, its pretty cool!

[HMC710]

Updated a bunch of drawings today so it's time to make some more parts!

[HMC710]

Got 4 blanks profiled today to our new profile. Numbers came out dead nuts so I'm happy there. New replacement 30 Luger reamer got here yesterday so time to set up a couple of new blow back uppers with the 22 UZ and the Tok killer!

[HMC710]

Just finished a 10" 9mm barrel and will set it up with our PDD system. The MDD system is working great and now just working on packaging. Hope to test fire tomorrow!

[22boomer]

Feb 17, 2016 19:47:54 GMT -5 HMC710 said:

Just finished a 10" 9mm barrel and will set it up with our PDD system. The MDD system is working great and now just working on packaging. Hope to test fire tomorrow!

Tim,
What's the difference between the PDD and the MDD systems. If these are the delay systems for blowback, I was wondering if a change needed to be made with the buffer weight in something like a 16" barreled setup?

[HMC710]

Hey 22, I thought you left the country or something!
Yes, they are both delay systems for the blow backs. As soon as I'm able I'll get the details out. In case a blind dog caught a rabbit I sent in some patent paperwork on what I've been doing.
Half the BCG system weight and still won't lock back the bolt? yea buddy!
More power than the Tokarev and won't lock the bolt back? yea buddy.
To answer your question, yes, it will work on the rifle systems. We had that a while back. (more on that to come.....) I wanted it to work on a true pistol set up (hint: no buffer tube......) so, screw it, I built the dang thing!
My next pistol is going to be a 30 carbine, and a .40 because it fits....and a 10mm cause its the same blank.... That will really test what we are doing.
Ran 2250 fps out of the 22 uz with the mdd last test session. The 30 Slugger hit **** fps......!!!!!! Let's just say it went Plaid........ with the mdd
This is from blow back pistols. I've got the 9mm down to 10 oz total reciprocating weight, 10 oz! Stock is 21.3 for bolt, buffer, and spring. I built a 25 oz buffer for the one of my Tok BB builds and used it on the 22 Reeds Express. That's when I got on the piston band wagon....
The pdd is a bit different but needs its chance to shine. two tests today, each improving on the last. Test 3 should allow for mag dumps in the 9mm.
When we finish breaking parts, get our paperwork back, and get these beta's rung out, I'll start offering kits and uppers. Or, its all going to fall to pcs and end up in the scrap bin.....
Stock upper receivers
stock springs - well, that's not true, they are a bit lighter.....
stock mags
stock 9mm adapters
stock bolts...... well, you can cut the back half off if you want.....
What's not to love?
Folding stocks?

Its great to be back at the shop!

[22boomer]

This all sounds great Tim. I hope all the paperwork comes through quickly so you don't have to worry about copycats. Years ago I had a 10mm blowback carbine and it was a bear to shoot -- felt like a 12ga shotgun. When it broke the plastic bumper on the end of the buffer I knew it was time to get rid of it. Too bad you didn't have your design out then -- it was probably 20+ years ago.

[HMC710]

Hey 22, I know what you mean. I did a Tok carbine and put an 8oz buffer and an A2 stock on it to lengthen out the pulse. It still rocked forward with all that BCG / buffer coming forward. We have two versions for rifles that are coming out next. We got confirmation of our patent applications late Friday afternoon on the way to the show so that was great news and is our primary focus.
We set up at the St Ignace Gun Show Friday night with our new AR Pistol on display.



These last two weeks have just been a blur between getting the patent info together (hopefully the next ones will go faster) building parts, getting the pistols ready, and doing the show. Got home last night after the 4 hr drive home and me and bro were ready for a cold one! Today is catch up, un pack, get back to work, and start planning for the next show in April.

Our New Pistol:
We are officially Patent Pending on our designs for a delayed blow back systems and are moving forward with development and sales. I'll be getting more information out in the next few weeks as I have 4 mules running and two more going out this week. As with any "new" idea, each one spawns 5 more and those 5 even more so we are letting our test data move us in the right directions. Here's what I can tell you for a fact on our new pistol blow back uppers:
1. So far we have cut BCG and buffer weights in half, so far. I had to de-tune the 9mm and 30 Slug'r to get them to lock back the bolt.
2. Yes, we have a new bolt assembly that lets you eliminate the buffer tube. Right now we are customizing existing bolts, but have our own bolt on the drawing board.
3. The delay systems will be manually adjustable for specific ammo or reloads. I used the same delay system on the Tokarev and the Slug'r. The Tokarev will do mag dumps but the Slug'r barely cycles the action even tho it has a heavier bullet and higher velocity! The difference is the powder burn rate so that's where the adjustment comes in.
4. I have one system with a "self regulating" system on it. It is on one of the 9mm and testing for soft reloads and factory +P stuff.
5. So far, the original charge handle is eliminated. Further testing will see if we can put it back on. Our pistol charge handles are now either on the upper receiver with a reciprocating side charger system or on the hand guard.
6. The MOD device is farther along than the POD device ( I changed the names because MOD is easier to say than MDD and I was getting funny looks at the show ) and they both are still describing what is going on.
7. All of this works with stock AR bolts, springs, and uppers.

So now you are asking how much and when will they be available. I am looking at a target price of $750 to $800 for a kit ready to go on your lower that includes a mag and an adapter for a 9mm length & rim dia round for barrels up to 10". Those would include 9mm, 9x23, 30 Luger, 30 Slug'r, 22 UZ

We are working hard to update our websites, www.heavymetalman.com www.heavymetalco.com www.revarlution.com and have added www.blowbackar.com and www.pistolar.com
I've been told by experts that the revarlution name should be dropped because its confusing to say and people don't want to be embarrassed, which I can understand. That's why Hornady went with Leverevalution I guess...... we will get it sorted out but right now, its time to get to work!
Thanks all.
Tim
Heavy Metal

[HMC710]

Lots more testing today and working with the POD system to get it as efficient as the MOD system. We have it 100% adjustable, but just don't have the timing down yet to stop factory ammo from locking back the bolt on a 10" barrel. I don't want to add any weight yet but, we are still about 8oz less than stock right now. Will try a couple more things tomorrow. We did solve a couple of issues and........ only one part failure so far and that was totally my fault.
Moving forward, I like it!

[HMC710]

Making more adjustments on the POD system and did a bunch of testing yesterday. Its nice to be at the shop and be able to act on an impulse instead of waiting a month or so! I keep thinking how nice it would be to have a test stand with scales and transducers to scientifically monitor all this stuff, kinda like the dyno my bike is sitting on. Should have new parts in a couple of hours

[HMC710]

Here is the test mule of our POD RAP system.



This is about version 6 and I'm going to run it until I break something. I like the "all in one" design where you just mount it on the barrel and go, but internally its more complicated (expensive) than I would like. The whole point was to keep it simple like the MOD SAC but I also want to increase power levels as much as possible. The set up was put together from my G5 Piston barrel so not laid out perfectly, but it reinforced our design and operational function from what we developed our patent information on. And, it all fits under the UTG Super Slim hand guards.

Next step is with the POD RAP is to get our folding / collapsing stock adapter on the rifle, should look pretty cool.

[HMC710]

We have been working on refining our pistol parts and getting the charge handle set up together. Right now I don't have room for a conventional charge handle and I've always thought they were clumsy to operate, no offense, but you need three hands to lock the bolt back without an empty mag in place. I've done a couple of the carrier "straight bolt" conversions and I was going to do the same thing here, but didn't want to cut up my upper receiver until I get our new test bolt done. With the MOD version of our pistol, the layout pretty much just made it simple for us.

For testing I just drilled and tapped our operating rod mount and had a simple reciprocating handle on the hand guard. The UTG Super Slim hand guard was milled out in the sides for clearance. That will be our base option for the conversions.



The op rod mount is the large ring with the square on top. That is how we connect the forward device to the operating rod (which is connected to the bolt through the bolt adapter)

For those that don't like the reciprocating bolt idea, we added non-reciprocating "handles" to both sides of the hand guard. The two small aluminum parts are the mount bases. Sitting above the mount bases are the two "handles" which look conspicuously like bolt on quad rail mounts......

Here is the assembly



The dual charge handles are on both side of the hand guard and independent of the BCG / Op Rod so you grab them like a pump shot gun or use individually. As of right now, they are not spring loaded and we'll see how things shake out for a while as we put more rounds through the set ups.

Here is a completed Pistol



Now to lock the bolt back just pull back on the charge handle(s) with your left hand and lock the bolt with your right. I've got a spring loaded folding handle sketched up but haven't knocked one out yet.

To summarize our new pistol, it uses 100% stock mil spec blow back AR parts. No special bolt, receiver, springs or hand guards. We have a patent pending bolt adapter, op rod, and forward device that allows us to cut the weight of the stock bolt. Typically we cut off everything behind the firing pin and that allows us to get rid of the buffer tube. For Rifle set ups you could add something like an ACE Folding Stock set up if you wanted. So far the most powerful factory ammo I've run is a Tokarev 10" and mag dumps are a breeze. The 30 Slug'r surpasses the Tokarev and the slower powder actually makes it even smoother than the Tokarev. Our focus right now is UZI mag rounds because adapters like the PSA and AMM Arms are well made and inexpensive. Plus, there are a bunch of 9mm out there all ready.

We have more to come on these as we move forward so stay tuned.......