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TonyRumore

Thinking about making a 3" S-12

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Maybe I'm just a nut-job, but after a few beers, I was thinking about making an S-12 shorter then 6".

Something around 3"......which of course is the complete length of the chamber.

My thought is to drill the gas port about 3/4" off the breech face, right through the side of the chamber and vent it into the gas manifold. The gas manifold would be bumped up against the receiver. The gas pressure would blow a hole right through the side of the plastic shotshell hull, into the gas manifold, driving the piston rearward to cycle the action.

 

I'm sure the internet jockey's will ask "why"........it's simply because high speed mechanical engineering is interesting to me.......I would get a warm fuzzy feeling if it actually worked.

 

Your thoughts?

 

Tony Rumore

Tromix Corp

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Sounds like fun! My first thought is, wouldn't you get little plastic "chads" in the gas system from the shells?

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.........thinking that if its actually possible that it can be accomplished, you can damn sure do it.........

After shooting that 6" running 3" magnums, I wouldn't want to shoot a 3" barrel more than 5-6 hundred times........YOW!!

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Sounds like fun! My first thought is, wouldn't you get little plastic "chads" in the gas system from the shells?

 

What might happen is that instead of clean chads, the plastic could indent into the gas ports and cause the hull to "key" into it and not eject. Or maybe this wouldn't be a factor taking into account the speed and heat involved. It would be an interesting experiment.

 

Do you already have an S12 with a ruined barrel?

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If this post had come from anyone else I would be making fun of them. :chris:

Why? WTF? Why be scared to make fun of a drunk engineer? If he pulls it off, you can always claim you were drunk when you posted and you honeslty always believed in him. There are lots of engineers out there mssing a finger, other parts of their body or have foreign objects permanently embedded in their flesh and bone.

 

My first thought here is there wil be zero choke. The wad will serve no purpose either. May not open up right either? So you might shoot at a target on the range and suddenly a small cesna drops out of the sky. To test it, maybe take an old single barrel, cut it to 3" (or 2 3/4") and see what kind of pattern you get when you shoot it. I am really curous about this now. I use to know a guy at Federal, I wonder if ammo manufacurers can give you a good idea of ballistic perfromance and issues on a round fired from basically no barrel?

 

 

PS at work today, I was thinking about a Saiga AOW. Not my first choice, but an SBS is the only thing I can not have in my home state..............go figure. An AOW pump is really a joke, but an AOW with a 5 round mag in semi auto is at least a good camp gun in bear country. I am not an AK builder and I assume you can not get virgin receivers BUT if you make the receiver, it seems you coud go down that path? Cut out the middle man!

Edited by Zoub

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Wow! Thats insane! (In a good way.) If anyone could do it I'm sure it'd be you. Has anyone ever attempted a shotgun that short?

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Someones been spraying MolyResin without a mask again :rolleyes: Hey, if you've got the motivation go for it.... If it doesn't cycle and you really want to go nuts with the engineering, try electro pneumatics on the carrier to cycle it? Your a trip sometimes.

Edited by 6500rpm

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I think it'll definitely breach the hull. Figuring out the gas port is gonna be tricky. I'd wear a heavy leather coat, gloves and a full-face mask the first time I shot it. The fireball is gonna be really IMPRESSIVE! If it works, I wonder how it'll bump? :D

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You could progressively open the port in the chamber until you get the hull to rupture.

I just wonder if you could get enough pressure to pull the ruptured hull out and cycle the action.

Since Saiga barrels are hard to come by you could take a single shot H&R and chop it down and then try the different port sizes until you get it to rupture.

I have an H&R Model 88 12 guage to donate if you are interested. It is just going to collect dust and take up safe space from now until I die.

 

Tom H (from Tulsa)

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hello All;

tony this is interesting. i think you will get a lot of gas out the breach. might blow the top cover off.

Zoub, you say you can own anything except SBS. if you can own DD you could always do a form 1 and build a less than 18 inch DD. just a thought.

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hello All;

tony this is interesting. i think you will get a lot of gas out the breach. might blow the top cover off.

Zoub, you say you can own anything except SBS. if you can own DD you could always do a form 1 and build a less than 18 inch DD. just a thought.

Yes I can own a DD. Thanks for the idea. I just found out there is a gun shop about 20 miles south of my new home who specializes in DD's. I think he does USAS 12's? I guess I need to go meet him and pose this question to him, but I have no desire to own a USAS.

 

Of course, if you can build a DD out of a Saiga 12 and did it, people in here might get hot about it? Shit man, I have only read a small amount about DD's. This is interesting. Can you build a DD of your own based on any 12 gauge?

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To me this is the realm of pure science. I feel the need for some length of barrel for the cartridge to speed up through, so at some point I would be looking into a shorter cartridge. In such a conversion, you may actually get better ballistics out of an Aguila short shell than a regular 2.75" shell, because the shot would have a longer effective barrel. If you did have a gas port using a blown out chad, it may need a self cleaning gas system of some sort, ie some way that the plastic would be reliably ejected.

 

It's always bugged me that barrels are measured and compared including the chamber. A 30-06 has about 1/2" less effective barrel than the same length barrel chambered in 308. That matters when you get down to 16-20". So in my book, an IZ-109 has effectively a 16.25" barrel, and this conversion would have a 0.25" barrel, using 2.75" shells. Ok, maybe a 0.5" barrel, considering that the shot starts from behind a crimp.

Edited by BattleRifleG3

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Not impossible idea.

 

...But plastic in gas chamber doesn't appel to me. I would make a gas collecting collar around muzzle. Germans had one semiauto rifle at the end of WW2 (Mauser, Sauer?) that collected gas pressure after barrel and used ring piston to operate mechanism. Now short stroke ring piston might also work here. Starts to remind Safir 410. It also used ring piston over barrel, with gas holes though. :lol:

But then again, AK needs both rails and piston to keep slide straigh. We did cut down one Saiga M3 to shorter than Krinkov and were able to keep piston quided even without gas tube. (Don't try to shoot regular AKs without one!) Now how to do that with longer stroke? SPAS-15 style quide rod? :o

 

 

-JumiKuula aka JamShot

Edited by JumiKuula

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I believe JumiKuula is referring to a muzzle-trap gas system, as found on the G41 and CZ-52 rifles-- originally designed by a Dane named Bang, if memory serves. It might just work, but it also might just fill up with more plastic from the lips of shot cups.

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Jamshot may be onto something....I'm thinking of a deal kinda like the booster on an MG-42.

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Im not sure it'll work... I dunno if the pressure will be enough to rupture the plastic hull considering the small port size. I'd say go for it though.

 

With a barrel that short I would just go direct blowback with the design, it shoulden't need to be ported. It shouldent be a problem to weld the bolt in place in the locked possition and remove the locking lugs. It may have a problem ejecting depending on the possition of the extractor/s. Im just going by memory here...

 

Muzzle velocity will be lacking but still a very cool "showtime" gun.

Edited by mike123456

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There were one proto version before G41 and G43 that had the gas-trap at the end of a muzzle. It didn't get too far since operating rods were too long and started bending. If I recall right it was equally as long as Mauser 98 and had the collecting cone at the end. Bang system was adopted after this failure.

 

Krinkov like cap might do as well as MG42 or Maxim booster.

 

 

-JumiKuula aka JamShot

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A straight blowback can't handle the 12ga round. A recoiling barrel that unlocks under recoil after the round exits is another story. And I still think an Aquila shell would be worth considering. The MAG-7 magazines through the grip may be the way to go. And it could be built from scratch as an AOW. Could be the shotgun counterpart to a DE.

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