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Post by HMC710 on Aug 19, 2010 17:50:48 GMT -5
Will start looking into the piston systems for the Tokarev. We have made a couple custom test uppers with pistons but have been busy with other things. Chime in with your piston info here..... www.youtube.com/watch?v=hitKrIXOnLYI was told this was a Teppo Jutsu upper and HM adapter
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Post by 22boomer on Aug 19, 2010 19:40:31 GMT -5
The fellow goes by "Ilove2shoot" over on AR15.com. He got Marty to make the first Tok upper back in 2002, a blowback, and I went and got the second one. He works for POF so I would think he got a good cut on the price of a piston system. There is more info at this loction: www.ar15.com/forums/topic.html?b=3&f=121&t=507320He did mention that the piston setup he has on the Tok is shorter than the normal pistol DI setup. edit to add: I asked him about the gas block position and he said the gas port is at 5" and that puts the gas block just far enough forward to allow access to the piston for cleaning. I don't know if the buffer, buffer spring and carrier are standard parts or modified -- I guess I should ask.
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Post by HMC710 on Aug 20, 2010 12:04:26 GMT -5
A 5" location is longer than pistols which are around the 3.6" mark. I'll see if Marty can share some info to minimize our learning curve. The two pistons we built were for much lower pressure than the Tok so I don't know how relavent they are. We did put one on a Tok brl and it ran, but not for long...... I would highly recommend going with the solid key piston carriers. Even the pinned and staked ones have not held up in our testing. I'll make a couple of calls and see what I can get for parts so we don't have to make them here. After I get the next batch of adapters out.....
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Post by 22boomer on Aug 20, 2010 18:24:32 GMT -5
I asked the fellow about the internal parts and he did just what I did with my old Tok barrel setup with the pistol length DI setup. He lightened the carrier, ran an empty buffer and a low power Wolff buffer spring. Too bad the keys are a problem because having to go to a true piston type carrier may jack the price some.
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Post by HMC710 on Aug 21, 2010 8:03:03 GMT -5
I tried out one of our piston set ups this morning on low power handloads and some Rom suplus. Gas port at 3.25 from ext shoulder & I had stock buffer & spring. The reloads (5 or 6 gr of unique if I remember) would not eject. The surplus would eject, but not pick up another case. I did not have my light set up to put in there so I'll try that next. I did bring in the piston & cyl to the shop to check them out. I used some plain steel for parts and didn't even hone the cyclinders. They felt rough so I am sure I am losing a lot there. I got some better materials in a few months ago when I started this project but got busy with other things.
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Post by 22boomer on Aug 22, 2010 15:52:25 GMT -5
Note sure what fails on the standard key when used in a piston system but I would suspect the small bolts used to hold the key on the carrier. There was a company that made a special, good sized pin that fit into the gas port on the bottom of the key and went into the gas port on the carrier. I don't know how hard the pin was but it was used to add the extra strength necessary to keep the key on the carrier under heavy use. Since the gas port between the key and carrier are of no use in a piston setup it seemed like a good idea. I don't know if this is of any value to your project or not.
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Post by HMC710 on Aug 23, 2010 5:22:16 GMT -5
On some of the first piston set ups, going back to the Rhino system, a large pin jounal was machined where the gas port on the carrier / key junction is. We have tried these and you have to keep the screws torqued and checked frequently. When we switched to the piston carriers, problem went away.
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Post by 22boomer on Aug 23, 2010 8:13:24 GMT -5
This is a link to the Adams Arms "how to pick the right length piston system" site. I know you already know all this but I was surprised at how short their pistol length setup is. adamsarms.net/images/gaslength1.pdf
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Post by HMC710 on Aug 24, 2010 5:24:59 GMT -5
Yes, their piston system is short. CMMG is a lot more cost effective but they do not offer a pistol length, just carbine and mid. I have not used either one.
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Post by love2shoot on Aug 26, 2010 10:52:48 GMT -5
My setup is sure becoming very popular. I had Marty at Teppo Jutsu do the chamber for me. it was cheaper then buying the reamers for a single barrel. If I do more, I'll get the reamers. everything else was done by me. while a few of the parts of "Off the shelf" POF parts, other parts needed to be modified, and a couple of custom parts needed to be made.
I really need to spend time and update my website and do a writeup about this upper on there, along with a thanks to HMC for the Mag adaptor.
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Post by 22boomer on Aug 26, 2010 19:59:12 GMT -5
I loved the part in the video about shooting the subsonics with the suppressor -- really really nice. I think that is where the piston setup really shines.
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Post by love2shoot on Aug 26, 2010 22:01:40 GMT -5
also the Corrosive ammo, that was the biggest factor for wanting the piston upper.....and the challenge of doing it.
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Post by HMC710 on Aug 27, 2010 8:02:37 GMT -5
Hi Doug, great job on the upper. ;D, and you are welcome on the adapter If there is anything we can do to help facilitate your production please let me know. I think the Tok piston set up is going to be big for the reasons Doug mentioned, cleaning. After running a buch of hand loads, I don't miss the cleaning, or the smell, one bit.......
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Post by 22boomer on Aug 27, 2010 8:09:48 GMT -5
HMC710, So, if I decided to make a gas piston system I would first have to locate a good carrier designed for the piston system. That would be in the $150 to $160 range. Would your system work with a standard piston carrier and is it low enough to fit under standard carbine handguards? Did you have any ideas as to an alternative to the available piston carriers?
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Post by love2shoot on Aug 27, 2010 15:48:55 GMT -5
I had some dirt on the carrier last time I shot, I know ot is from shooting it suppressed....basicly for the most part, I use Windex to clean that rifle Thinking about getting another of you adaptors that use the bottom release instead of the standard AR mag release.
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