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 Post subject: Suppressed Vepr 308?
PostPosted: Sat Oct 14, 2017 2:41 am 
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Joined: Thu May 08, 2014 11:51 pm
Posts: 28
Anybody put a suppressor on a Vepr 308? What all needs to be done to mount the suppressor? What is the end results? Is the rifle way overgassed as a result? Etc?


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 Post subject: Re: Suppressed Vepr 308?
PostPosted: Sat Mar 17, 2018 5:24 am 
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Joined: Thu Aug 08, 2013 9:44 pm
Posts: 20
tbryanh wrote:
Anybody put a suppressor on a Vepr 308? What all needs to be done to mount the suppressor? What is the end results? Is the rifle way overgassed as a result? Etc?


No, I haven't or heard of it. You would probably need to remove the flash hider and front sight then thread the barrel.

My Vepr is over gassed to start with, a suppressor would only worsen the condition.

Short answer? Yes you will need to modify the gas system on almost any gas gun to shoot suppressed successfully.

I have been working on ideas for the Veprs gas system, though I am not trying to suppress mine, just tame one of mine some.

I have two Veprs one is unmodified and the other is 922r and nothing Russian will be left on it when I am done accept the barrel, dust cover and receiver/trunion. I picked this one of the two to modify because it was the least accurate of the pair. Cold bore three shot groups avg usually around 1.5 to 2.5. The stock Vepr is a consistent sub MOA rifle in the right hands. Despite weighing less, it doesn't recoil as much as the other and it never has. I have put it down to the diameter of the barrel's gas outlet, but I can't say that's it for sure.

Regardless, I have come to believe that it has to do with the gas system, as I switched their BCG's and it didn't matter. They are only 6 SN's apart by the way, and appear to be identical except for recoil, accuracy and the severity of case dinging.

I really believe that accuracy on the Veprs can be improved by timing the cycle and eliminating/reducing BCG Slam through adjusting the gas volume and Guide Rod Spring...

I have looked at several means of controlling the BCG's speed and timing, and of the several I have seen and considered so far, these three are the ones I expect that I will adopt:

https://www.knsprecisioninc.com/product/ak-adjustable-gas-piston/ - I just received one - haven't installed it yet.

http://www.thefirearmblog.com/blog/2017/08/09/new-definitive-arms-adjustable-ak-gas-block/ - Can't find it yet...

https://dpmsystems.us/products/ak-47-rifles-5-45x39-7-62x39 - Waiting for this to come back in stock.

Most likely I will also cut the barrel down to 18 or 20 inches to stiffen and time it, crown and thread the barrel and then install a brake/compensator. Also been thinking I will have the barrel and receiver Cryro-Treated before I get around to doing a Cerakote or GunKote job on it.

At that point I am hoping that developing a few optimized hand loads won't be like putting lipstick on a pig...


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 Post subject: Re: Suppressed Vepr 308?
PostPosted: Sat Mar 17, 2018 2:16 pm 
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Joined: Thu May 08, 2014 11:51 pm
Posts: 28
For some time I was under the impression that the overgassing of the AK was affecting accuracy and if the gas port was shut off, the AK would be as accurate as a bolt-action rifle. This may not be the case.

One builder in particular in another forum said he put an AK together without drilling the gas port. He tested the accuracy of it, then drilled the gas port and tested the accuracy again. He said there was no difference in accuracy. It seems from this information that it is the explosion from the detonation of the round that causes the barrel to ring. This ringing is what affects accuracy, not the cycling of the bolt carrier.

The tightness of the chamber I think can affect accuracy too. The chambers on AK barrels might be deliberately a little loose to ensure rounds feed and eject reliably. Target barrels might have tighter chambers to insure the alignment of the round is the same for each round. This increases accuracy but decreases reliability.

Chrome lining decreases accuracy too. The grooves are not as precise once the chrome plating is added.

It appears there is a tradeoff between accuracy and reliability.


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 Post subject: Re: Suppressed Vepr 308?
PostPosted: Wed Mar 21, 2018 4:57 am 
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Joined: Thu Aug 08, 2013 9:44 pm
Posts: 20
Tbryanh, you are correct there is definitely a trade off between accuracy and reliability. I would still like to improve my rifle's accuracy and preserve it's accurate barrel life, as well as the rest of the rifle’s life.

I never thought that it would be AS accurate as a bolt rifle… but, I too am hopeful that it will tighten groups up at least some.
I will check for it by opening the gas piston's valve all the way and see what I get for cold bore groups of three with bolt locked throughout the shot, vs the minimum gas to cycle the bolt, and then with it closed all the way.

The builder you mention is correct, if the harmonics aren’t right, i.e. the bullet exiting the barrel right at the instant when it is whipped through the line starting from the firing pin and ending at the point of aim; then the bullet exits the barrel when it’s whipping has it pointed elsewhere. Gradually shortening the barrel and re-crowning as I go, it is possible I will find the proverbial harmonic sweet spot. Regardless a shorter barrel is a stiffer barrel, and stiffer barrels do whip less…

AKs not only have barrel whip (like every rifle), but receiver/trunnion flex which is also changing the orientation of the barrel during the shot. Veprs are designed to have less, but it is still there. Bolt Slam is just one of the factors that can affect accuracy. I hope correcting for it helps, it certainly will lessen the wear and tear on the rifle and me...

Regarding chambers... reloading allows for tweaking cases and adjusting bullet seating depth to correctly gauge the jump of the bullet to the lands for a individual barrel/chamber too.

Yes chrome lining does decrease accuracy. That’s why I am also going to give these bad boys a try too!

https://www.midwayusa.com/product/100192877/tubb-final-finish-bore-lapping-ammunition-308-winchester-box-of-20

Cryro treatment is cheap and it also reduces whip and wear too. That will be the last step in wringing the rifle out, after that it is just a matter of wringing me out…

A target rifle it will never be, but that was never it's purpose for me. It was always meant to be like it's 308 caliber and cartridge. Not perfect; but still a natural simply good all around, never-fail blaster.


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 Post subject: Re: Suppressed Vepr 308?
PostPosted: Wed May 30, 2018 9:43 pm 
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Joined: Fri Aug 08, 2014 7:04 pm
Posts: 127
Kns precision adjustable gas piston may work for your goals of suppression.


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