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Post by HMC710 on Aug 19, 2010 6:15:52 GMT -5
Hi Members and Guests, We are getting increased orders for the blowback systems and have been trying to get to the adapters. I worked on the modified drawings and programming last night and hope to get it out to the machine after this run of standard adapters. We also have a prototype blowback upper running using the stock mag and adapter, but a uses a modified bcg. It is running, but still needs some tuning. I can say that the gas system is much smoother at this point. I started this new thread to focus on the blowback side of things. Thanks, Tim Aberegg Heavy Metal
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Post by HMC710 on Sept 16, 2010 6:00:59 GMT -5
Program done and tested. Cut Job1 yesterday and tested. Feed and eject 100% ;Dwith some minor mods. Will rev program today and re-test. Finally
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Post by HMC710 on Sept 18, 2010 7:32:22 GMT -5
;D Tested 4 adapters yesterday and these blow backs ROCK! Will disect my notes and measurements today and see if we want to make any changes. Have a field tester reporting the FA test was 100% Thanks D!
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Post by 22boomer on Sept 19, 2010 17:42:10 GMT -5
When I was at the range on Saturday, there were people there interested in the 7.62X25 in a blow-back version. They had colt style 9mm carbines and wanted to get into the Tok round. I told them to google for heavy metal Co. I said you were going to be making barrels to use in the 9mm blow-backs and you'd have a magwell adapter available soon. I forgot to tell them about the mags. I hope they are serious about it.
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Post by HMC710 on Sept 20, 2010 17:54:32 GMT -5
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Post by HMC710 on Sept 22, 2010 6:50:28 GMT -5
Stock carbine buffer: 2.88 oz on my scale Max Buffer (prototype) 7.52 oz on my scale The Max Buffer was a test on another project so I'll run a couple on the new ones and see what they come up as solid and maybe with some of the tungsten weights. One way to add more weight is to go tungsten $$$ Buffer weight info: (per info I have seen posted: use at your own risk) Carbine = 3.2 H = 3.8 H2 = 4.7 Rifle = 5.2 H3 = 5.5 Q = 5.47 - 8.5 On testing the blow back adapters for the Tok with a carbine stock, the max buffer made an improvement over the carbine buffer. A extra power spring might have done the same thing, but I have been focusing on lighter projects as opposed to these heavy projects so I don't have one handy. I have always tried to reduce weight and now with the blow backs I am adding weight. I also am going to try a rifle buffer tube assembly to give more dwell time and see what that does along with another idea we are working on.
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Post by 22boomer on Sept 22, 2010 9:19:53 GMT -5
That preliminary buffer looks good. It would be nice if it had the tungsten weights inside to give it that dead blow hammer effect. I have no idea what the Colt 9mm buffer (5.47gr) is made of but it gets the dead blow effect by having a loose fitting head. You can see the hole size for the roll pin in the outer shell is way too big so the head rattles. I don't know what would be cheaper to make -- your big buffer that's hollow and has loose tungsten weights inside or a two piece like the Colt 9mm? Ramping of the bolt causes a little less restriction on the bolt since the hammer can be pushed out of the way easier. This adds to the need for a heavier buffer. A heavier spring is good but more for decelerating the buffer and bolt. I've been using a Colt 9mm buffer with a standard carbine spring and it seems to work but the shoulder on the commercial (S&B) Tok ammo is pushed forward more than I would like to see. This is out of a 16" barrel.
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Post by HMC710 on Sept 22, 2010 11:07:18 GMT -5
With the way people complain about tearing up fcg parts it would seem like those roll pins would be the first to go, unless there is an internal shoulder. Tungsten would at 2x the wgt of steel but about 10x the cost
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Post by 22boomer on Sept 22, 2010 16:57:38 GMT -5
I don't believe the 9mm buffer roll pin takes much of a beating since the buffer head butts up against the buffer body on firing. The buffer spring may spread them apart as it drives them back home but that's nothing like the force of the round being fired. The body of the 9mm is fat -- I'd have to measure it but it fits tight in the buffer spring so that may also retard some of the beating. I had a 357sig blowback AR that I used an "X" buffer made by SAW. It was 8.0 oz. and cost $100. It tamed the Sig round. I originally used a Colt 9mm buffer but it impacted the rear of the buffer tube so hard that it cracked the plastic buffer tip. It felt like a 12ga magnum shotgun with that 9mm buffer.
I was thinking a 6.5oz. buffer would be perfect for the blowback Tok but then it would have to be tested with both commercial and milsurp ammo to make sure it works ok.
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Post by HMC710 on Sept 23, 2010 6:06:22 GMT -5
I'm going to run a couple max buffers and do one with the weights I took out of my super lite set up and see what they come out at. I needed to run the max on the tok blow back and I think I'll get an extra power spring also.
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Post by love2shoot on Sept 23, 2010 17:16:32 GMT -5
the weight moving inside the buffer helps stop bolt bounce.......I think I used to use a 9mm on the blow back.....it has been awhile since I played with mine.......hard to even think about it with my other setup.
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Post by HMC710 on Sept 24, 2010 16:08:20 GMT -5
.......hard to even think about it with my other setup. Blow back does run harder and I'll post pics of the mag and adapter after a couple of days.... Going to try hosing it down with windex or brake clean after the next run and see what happens.
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Post by 22boomer on Sept 26, 2010 9:29:53 GMT -5
.......hard to even think about it with my other setup. Blow back is does run harder and I'll post pics of the mag and adapter after a couple of days.... Going to try hosing it down with windex or brake clean after the next run and see what happens. Blowback does run harder but not that much. The gas systems (DI and piston) are just very light in their recoil. I saw that video you did where you showed the spent milsurp cases and the magazine with the magblock showing corrosion after a couple of days and that was good to show because it emphasized the problem -- but most people would clean their weapon the day they fired the milsurp. I went through 100+ rounds of milsurp last weekend, gave it all a spritz with the windex and then hosed it off with hot water in the kitchen sink. When it all dried I did some #9 down the bore and sprayed some CLP in the FCG. I just swished the magazine around in the hot water a second and that was it. I will say that the weight of the buffer controls how early the brass comes out of the chamber and a little more weight (like your Max buffer) will help to lessen the crud coming out. Don't get me wrong, I love both the DI and piston setups but the blowback is a system that many people have and it needs to also be addressed as far as shooting milsurp Tok ammo.
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Post by HMC710 on Sept 26, 2010 12:07:39 GMT -5
Blow backs will always have their place and followers like everything else. Haven't got to the new buffers yet, been kinda busy.... ;D Got some heavy springs ordered also to see if we can smooth things out a bit. Windex works wonders, cut my cleaning time in half. I let the one mag sit to see what would happen....
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Post by HMC710 on Oct 7, 2010 6:22:07 GMT -5
Shipped out the first blow back adapters yesterday and will see what the field reports say. Ordered some Wolf springs and setting up to run some Max and SuperMax (w/tungsten wgts) buffers.
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