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Selectable gas system fix


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Herb Adams was a brilliant automotive engineer, from whom I learned a tremendous amount. The most important principle that he taught was in engineering everything you do is a compromise of some other factor. There are no freebies. To make something heavy duty, means it usually heavy. If you make TSL bogge super swamper tire to go through the deepest mud it doesn't do so hot on road noise and mileage. So what I learned when I design something is to consider all of the factors average that out and come up with the best possible solution. Price, availability, ease of installation, versatility, and effectiveness are just some of the factors that need to be considered. Springs are an excellent tool to To a gun with. The compromise is, they are at the back of the gun. And the gas system starts at the front of the gun. Therefore before the spring has a chance to interact the entire action has already been acted upon the entire "action" has already been acted upon, affording no protection except for the rear trunnions.

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Let's talk about springs shall we? Springs are measured in rate. That rate corresponds 2 pounds per inch of movement. So an 18 Spring is in fact 18 pounds to the press it 1 inch. And so on and so forth. Where this gets interesting is when you start to look at an elastomer such as the type that buffers are made out of. What you find is they also have a rate. There's our progressive though. Much like you can buy a progressive rate spring. Now without getting into the dynamics of spring calculations and modules of elasticity(which I can if you want on another thread) what the rate ends up being on that type of material is the initial rate is zero, and the final rate is infinity. The reason they use this material as bump stops on A-frames and suspensions when the original coil spring cannot control the forces is it Contacts softly at first and continues to ramp up exponentially to resist the force until it does finally control stop the motion. There is an appropriate application for this principle. It is however an end the wine last ditch effort to prevent a metal on metal collision. So now that we see that a coil spring and a piece of rubber or polymer are both in fact springs. Why don't we just grab a handful of buffers slap them in the receiver, grab some 3"inch magnums and letter fucking rip!

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Please excuse my grammar, I will blame it on my iPhone, as I'm driving thousand mile trip and started at 4:30 this morning. I do not however at this point wish to apologize for my passion. If there isn't things in life that get you excited make you feel alive you need to get off the fucking computer! Lmao

None of my comments dismiss what Jack suggested, I will let it be stated however though that tuning with the recoil spring on the piston operated Gun should not be a starting place. It is however excellent for fine-tuning let's say getting that last 2-3%

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I was very pleased with it. Thank you. It's fun when you predict something, but it's even more exciting when it orks! I know, you know, that feeling. I will trade numbers for satisfied "individuals" any day of the week. I'm not sure what you got cooking over there at evlutionz but it sure smells good, hopefully we're going to get a taste of it soon!

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So is the single puck adjustable? Or are there different pucks for each? I'd love to see the adjustment method if it's one puck with different settings. I understand if your waiting to unveil the design until You get all the patents in order

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I have 3 VEPR 12's and I am very interested. BTW, will it work on the Saiga 12 type 030 Shotguns also?

The saiga 030 has a different length op rod, and corresponding depth change for the pocket on the puck. So the pucks are different Vepr 12vs Siaga 030. There seems to me more veprs so I will build that model first. I do intend to provide the system on the saiga platform too. Once production has started it will take very little to release the izzy option.

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Id be interested. Wish someone would make something as well to beef up the op rod/bolt carrier connection, let alone a replacement oprod/bolt carrier for it...like a bolt carrier and op rod thats all one machined piece. Its threaded out to meet the gas puck I guess. But im suspicious about the fatigue on the threads of the bolt carrier there. I wonder if putting a couple light tack welds on it could beef it up and take the stress off the threaded connection? My VEPR would probably be overgassed if I shot 3" magnums so im sticking with everything 2 3/4". I dont think recoil is that bad on mine and im about to add a GK-01 muzzle brake.More worried about integrity of the action.

Edited by asdaven
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Yeah but considering my 870 has practically a 30" barrel and weighs more probably compared to the VEPR with a 19" barrel and light weight furniture , I was pleasantly surprised. And that was without a muzzle brake. Now I got one of the clones of the GK-01 brake for it so ill have to how it works. Recoil is practically null with low brass target loads.

 

Yeah the op rod im not concerned about the exposed threads but rather how far its threaded down into the bolt carrier and the strength of all of it. They peened it so you cant unthread it but I dont know why they just didint weld it to the bolt carrier for rigidity and strength. Unless the design requires the op rod to have some latteral play. This to me would be the first thing to wear out if its being overgassed. Unless its smacking the back of the reciever and the whole gun is banging it self apart.

 

Is there no way for the gas to bled off with this design? I wouldve thought they would just put some vent holes in the gas tube somewhere like a normal AK. But of course most 7.62x39 rifle ammo is loaded around the same specs? There is carbon/soot in the gas/op rod tube behind the piston. So the piston must allow some gas by.

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Yeah but considering my 870 has practically a 30" barrel and weighs more probably compared to the VEPR with a 19" barrel and light weight furniture , I was pleasantly surprised. And that was without a muzzle brake. Now I got one of the clones of the GK-01 brake for it so ill have to how it works. Recoil is practically null with low brass target loads.

Yeah the op rod im not concerned about the exposed threads but rather how far its threaded down into the bolt carrier and the strength of all of it. They peened it so you cant unthread it but I dont know why they just didint weld it to the bolt carrier for rigidity and strength. Unless the design requires the op rod to have some latteral play. This to me would be the first thing to wear out if its being overgassed. Unless its smacking the back of the reciever and the whole gun is banging it self apart.

Is there no way for the gas to bled off with this design? I wouldve thought they would just put some vent holes in the gas tube somewhere like a normal AK. But of course most 7.62x39 rifle ammo is loaded around the same specs? There is carbon/soot in the gas/op rod tube behind the piston. So the piston must allow some gas by.

So you don't have a prob, you gun works great, you have a concerns about a 67 year old op rod design will millions and millions of working units. Explain your post again to me. Did you have question or comment?
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Yes, but it would be expensive and require moddification to the weapon, therefore shipping/smithing cost also. I'm working on a "drop-in" first so everyone a least has one option available to them, at a reasonable price point, as right now there is nothing. If there was an easy fix, directly crossbred from the spotter saiga you can believe it would be on the market already.

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So you don't have a prob, you gun works great, you have a concerns about a 67 year old op rod design will millions and millions of working units. Explain your post again to me. Did you have question or comment?

 

Yeah but that 67 year old design is for a 7.62x39 rifle round, not a 12 gauge. The VEPR 12 is based off of the Saiga 12 which has been around I guess 10 years. And yeah same aspect with minor modifications....reciever opened up for 12 gauge shells, bigger bolt head, barrel, etc. But the AK shotguns completely have a different gas system. Theyre short stroke instead of long stroke. The op rod is seperate from the gas piston.

 

But my point is the connection between the op rod and carrier. Its not fully threaded in. Seems like its only threaded in by a few threads. If you read on forum accross the internet, broken oprods and cracked bolt carriers are a major point of concern with the Saigas and even our "refined" VEPR 12. And if either of those break or both, its extremely hard to find a new bolt carrier or op rod if not impossible unless someone custom makes one. Point being im extremely interested in a gas system fix. But id like to beef up the gun in that area. A fix could be a op rod that is the correct length that it can be threaded all the way in or a machined one piece bolt carrier and op rod. Someone on one of the other forums was talking about creating a fix for this problem, but I forgot where.

Edited by asdaven
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IIRC "the Cobra" was looking into a HD op rod option. He was hot on the trail of the same concerns you are having. He seems to be very knowledgable and able to deliver. If I was looking for a beefed up op rod I would contact him directly.

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Sounds good. That and a gas system fix would probably make this gun perfect . Looking at the op rod again, its threaded down farther than I though. Must just have a long threaded section. It might be alright provided that the heat treating is good on the threaded area.

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Humm???.... I have 2 Vepr's 12's and have owned 3 Saiga 12's, (even going back to when they were $189.00 from CDNN). In my opinion , the Vepr's are a big step up from the original style Saiga platform in quality, (GEEZ, I didn't have to pull the barrel and uncover the gas ports OR re-drill any covered ones!).. My only interest is in shotgun competition, during which a mixture of  #71/2 birdshot / 00 buck and or slugs are usually required to complete the course of fire. Maybe, I'm missing the boat?.... I can't imagine a heavier recoil spring allowing the shotgun to function under these rapid fire conditions as ejection is the issue with "lighter FPS" rounds..(I have many Colt springs and know that "lighter "springs are the norm in competition. I run a 8 # spring in my 2011 SV compensated "open" 9mm pistol).  I've gotten the Vepr's  (with SGM 12 round mags) to reliably function with 1255 feet per second birdshot by using a cut stock front spring (3 coils) and have experimented with a lighter puck (ala Papa Zoro's post). I have the CSS version of the "tank break" on one gun and I just had the 22' barrel on the 2nd. EDM ported on the other. Of course the contoured  / polished Tapco trigger groups / bolts, etc. for "922" BS. Pic of the 22' gun.

 

If you can point me to any other improvements?, PM me or post. Mike in Arizona

post-3152-0-10118400-1402584163_thumb.jpg

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  • 1 month later...

Humm???.... I have 2 Vepr's 12's and have owned 3 Saiga 12's, (even going back to when they were $189.00 from CDNN). In my opinion , the Vepr's are a big step up from the original style Saiga platform in quality, (GEEZ, I didn't have to pull the barrel and uncover the gas ports OR re-drill any covered ones!).. My only interest is in shotgun competition, during which a mixture of  #71/2 birdshot / 00 buck and or slugs are usually required to complete the course of fire. Maybe, I'm missing the boat?.... I can't imagine a heavier recoil spring allowing the shotgun to function under these rapid fire conditions as ejection is the issue with "lighter FPS" rounds..(I have many Colt springs and know that "lighter "springs are the norm in competition. I run a 8 # spring in my 2011 SV compensated "open" 9mm pistol).  I've gotten the Vepr's  (with SGM 12 round mags) to reliably function with 1255 feet per second birdshot by using a cut stock front spring (3 coils) and have experimented with a lighter puck (ala Papa Zoro's post). I have the CSS version of the "tank break" on one gun and I just had the 22' barrel on the 2nd. EDM ported on the other. Of course the contoured  / polished Tapco trigger groups / bolts, etc. for "922" BS. Pic of the 22' gun.

 

If you can point me to any other improvements?, PM me or post. Mike in Arizona

the improvement will be made in longevity for those that will only fire full power ammo and lightened recoil.

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I really didn't want to rain on anyone's parade, but all you have to do is replace the recoil spring with a heavier spring if you feel your shotgun has too much gas.

 

I worked on a Vepr today, that barely would cycle Federal Bulk Pack.  They are all a little different.

 

Just because the shotgun came with "X" springs, does not mean they are consistent with the type shot shells people put through them.

 

It doesn't matter if it is a delayed blow-back pistol (1911) or a shotgun, they all can benefit from installing the proper springs for the shells being fired through the system.

 

It is day and night difference when the system is properly tuned.  Less felt recoil and less perceived muzzle flip.

 

Just go out to the range, with an assortment of spring and start changing them bad boys. 

 

You will find the combination that works for both your shooting style (mainly pistol) and the ammunition you are using. 

 

Standard Government 1911 Springs may be utilized as replacements.  Stock springs are at an average of 16#. 

 

Try an 18, go up a pound until the shotgun doesn't want to cycle properly and then start finding the perfect balance between performance and reliability or go down if your shotgun does not fully eject. 

 

You want a very fast action.  The fastest possible without causing any physical damage!

 

Jack

 

I am a little confused by the stock recoil spring tensions listed in this post.  I know you can use 1911 springs for your Vepr or Saiga 12.  I also know the standard weight for a 1911 is 16 lbs.  Am I reading this correctly that the stock weight for a Saiga/Vepr 12 is also 16l bs?  I was under the impression that it was anywhere from 20-22 lbs for stock recoil springs for Saiga/Vepr 12.  It seems this has come up on tons of posts, but nothing concrete.  

Edited by warthog984
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  • 1 month later...

Unfortunately, I don't have any updates. I just do this as a hobby. I have been working out of state on a 5 millon dollar project. Like most on here, I have to pay the bills first. I will have a reputable business sell the product. Just have to do my part and get it to them. Thank you for your patients. Will update as this progresses.

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