Captive Piston Technology

[LavaRed]

The protruding length of the piston should not exceed the length of the bullet when seated on an unfired cartridge, to permit reliable feeding in an unmodified weapon.

[delta9mda]

its all in Al Paulson's book silencer history and performance vol 2.

the piston does project into the chamber it seems as the base mates with the rear of the barrel for a complete seal.

[solitary.phoenix]

Just for anyone who may be keeping up with this thread, here's a link to yet another captive-piston weapon that I've been reading about. It's the U.S Equivelent of the OTS-38. This is now my favorite piston-cartridge platform...I am absolutely enthralled. Evidently, S&W decided that a scatter-pistol would be a better instrument than a solid projectile launching weapon. This particular cartridge put tungsten shot in the air at 730 ft/second, which is respectable. I would imagine it's muzzle energy to more effective for antipersonnel use than the PSS or OTS-38, at 135/ft lbs.

Link: http://world.guns.ru/handguns/double-ac ... ver-e.html

Scatterpistols are a most interesting concept. I have many, many ideas and sketches that I would like to post here but it would be much better to just show you a working prototype. To avoid legal problems, I will most assuredly be seeking a local licensed silencer manufacturer to help create prototypes from my diagrams.

And thanks for the lead, delta. I need to get that volume, I greatly respect Paulson's original work. More to follow...

[jlwilliams]

Maybe you could use a Taurus Judge pistol as a starting point. It has an even bigger cylinder than the S&W 44mag that the OTS-38 was based on had. It seems like the limiting factor on the performance of the cartridges is the length of the piston's travel. A traditional cartridge accelerates the projectile for the whole length of the bore while a captured piston only pushes to the end of the stroke. The bigger the cartridge, the better. The .410 is about as big a chamber volume as you will find in common manufacture. You can also use a 410/45lc Comanche as a cheap balistic test bed. That way if you blow up an action you do it on a $200 gun not a $500 gun. Just do it in a vice with a pull cord on the trigger.

I like the captive piston concept. It certainly has it's limitations, not least of which being the classification of each round as a taxable suppressor, but I can see how a dead quiet snubby revolver or derringer could be useful. Not a use it every day gun; but worth persuing the concept with the benefit of new technology, new materials and the all important new perspective. Try it again, just a little different than what was done in the past. Maybe it flops, maybe it flies.

Watching with interest.

[Emilio]

This or quiet powders could have ATF problemos, beside lasers are the future.

[doubloon]

Quiet powders ...

http://www.youtube.com/watch?v=7LjnhhtHojM

[bobtail101]

A few years ago I posted here about a 6mm silent piston cartrige I
had made HERE IN FRANCE using a shot gun primer as a power source as my cartrige was fired out of an adapter in a single shot 20 gauge.
It was just a toy and probably went out at about 90m/s as calculated by the campbell soap dint test compared to an airrifle of known velocity but there was LITTLE OR NO NOISE
Since then I've done nothing in that dirction but these posts have brought back an idea I once had .Apparently someone in california used to make an adapter cartrige 30/30 sticks in my mind where a .22lr cartrige had its bullet snugged up inside the 30 caliber slug. Probably a case with an auxillery rim fire firing pin was used as in normal adapters in 222/223. It seems to me they were getting 700 ft/sec
S o what if you produced a simple lathe turned long pistol shell ie 357 max chambered in .22 at on end and .357 on the other with 2 or 3 mm of metal drilled with a 4 mm hole between the two You could use various .22 shells from bb caps up to long rifle but hi velocity shorts with the bullet cut off flush with the case should give good power and allow longer piston travel.T he 357 bullet (light) would fit in the case on top of the secondary piston .I used a steel 4mm nail before so the sharp pointed part of the nail would sit on the .22 bullet and the head of the nail under the .357 bullet .
The .22 bullet would serve as a primery piston and would I hope not swage down to go through the 4mm hole also the .22 casing should expand and hopefully prevent primer setback as in the revolver used in Vietnam. Obliously the secondary piston would follow the bullet out the barrel and might gauge the barrel but it does prevent the cylinder binding up in the case of a revolver for exemple
Just day dreaming but there must be other people out there with ideas they'll share withno fionancial gain at the end

[Chic]

My idea was for a gun incorporating a captive piston. I was thinking along the lines of a 12ga using 357 mag or 327 mag inserts driving the captive piston. My reasoning is that is that the powder burns better with higher pressure and provides high initial acceleration. Once the small amount of powder achieves the high pressure and acceleration, the gas enters the 12ga bore where there is lots of expansion room. For home defense, buckshot could be used, for survival hunting, a saboted .45 bullet at 950fps would have a much better trajectery than a bow. If the piston was stopped with a spring, it might last for a considerable number of shots.

Regarding legality, on another site, someone stated that in the 1980's, captive piston technology was not considered a silencer. The US Code definition states:
(24) The terms “firearm silencer” and “firearm muffler” mean any device for silencing, muffling, or diminishing the report of a portable firearm, including any combination of parts, designed or redesigned, and intended for use in assembling or fabricating a firearm silencer or firearm muffler, and any part intended only for use in such assembly or fabrication.

With this design, the firearm is silent, rather than having a device silencing the firearm. Common sense means anyone should be absolutly sure before making one.

Note that there is also silent mortars using this principle.[/color][/color] They slide the tail of the round over a rod and a piston in the tail pushes it off the rod. See:

http://articles.janes.com/articles/Jane ... eorgia.htm

http://articles.janes.com/articles/Jane ... rance.html

[FullHouse]

its all in Al Paulson's book silencer history and performance vol 2.

the piston does project into the chamber it seems as the base mates with the rear of the barrel for a complete seal.

Paulson also talks about captive piston technology. It is still around and not just with the Russians. Arms Tech makes the 6mm HazMat, but it is only available to Gov clients. On the note of the Captive piston gun. I would think that your piston system would be " device designed for silencing, muffling, or diminishing the report of a portable firearm even if it also was used in the function of the firearm. Cool Idea, but I don't think it would be viewed any different than any other integrally suppressed firearm. I would definitely suggest doing a Form 1 before toying with/testing your idea.

[jlwilliams]

IIRC, someone posted that there has been some ruling by the BATFE to the effect that they would consider each round taxable. I'm not sure but I think the alphabet boys have spoken.

6mm HazMat? Never heard of it. I'll ask my buddy Google what he knows. That should be a neat surf.

[dragoon]

No first-hand experience , but I read that the Vietnam-era 12 gauge shell , in number 4 buckshot , had an effective range of about 25 yards , and made a hissing noise as the gas bled off . It was probably fired out of the Ithaca M37 (18" barrel) ... The S&W revolvers mentioned above were for a program to give tunnel-rats a more efficient weapon , also during the VN conflict ...

[LavaRed]

No first-hand experience , but I read that the Vietnam-era 12 gauge shell , in number 4 buckshot , had an effective range of about 25 yards , and made a hissing noise as the gas bled off . It was probably fired out of the Ithaca M37 (18" barrel) ... The S&W revolvers mentioned above were for a program to give tunnel-rats a more efficient weapon , also during the VN conflict ...

The problem with hissing noises is that they tend to be rather sharp and not easily confused with other ambient sounds, especially in the outdoors. An effective suppressor must not only achieve the better sound pressure levels, but also produce a sound that can easily blend in or be mistaken for something else.

[Historian]

This seems like the opinions of someone who hasn't had a lot of experience with silencers. Like an amish guy trying to reinvent the automobile.

+1 I shall definitely steal this comparison!

[doubloon]

This seems like the opinions of someone who hasn't had a lot of experience with silencers. Like an amish guy trying to reinvent the automobile.

+1 I shall definitely steal this comparison!

[Kramer]

IIRC, someone posted that there has been some ruling by the BATFE to the effect that they would consider each round taxable. I'm not sure but I think the alphabet boys have spoken.

There was an article in the SAR mag a year or two ago about this stuff (I think it was the Russian round) and it stated that each round would have to have a stamp.

[Maestro]

If you addet an suppressor together white 30 -40 db and you have 20 -30 from the captive ammunition then it stacks linear to 50 - 70 ??
What say the physic to that ??

[garandman]

So you want to make cans obsolete and you posted this on suppressor board.

Sounds to me he wants to make ATF obsolete. A-fricken-men to that.

You are of course free to continue sending them a $200 privilege tax for every suppressor you wish to own.

[TROOPER]

If you addet an suppressor together white 30 -40 db and you have 20 -30 from the captive ammunition then it stacks linear to 50 - 70 ??
What say the physic to that ??

Is this a serious question?

A whisper is 15 db. A jet engine is 120 db.

If you get 8 people whispering at the same time, it will be as loud as a jet-engine.

If you get 10 people whispering at the same time, its as though an SBR .308 is going off next to your ear.

Is this a serious question?

[garandman]

If you get 10 people whispering at the same time, its as though an SBR .308 is going off next to your ear.

1000 people whispering at the same time on the planet may knock it out of orbit. Hey - can you PROVE it couldn't happen?

[ick]

Everyone knows the future of weaponry is the Weirding Module.