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Vepr 12 Gas Block Removal Port Work and reinstallation.

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Heres some background on the situation. I have a vepr 12 that refused to run reliably any 1200 fps loads. It was running the 1290 stuff barely and weakly ejecting and dove loads at 1300+ were the same issue with similar reliability issues. My first step was to polish the hammer face and underside of the bolt carrier. This was still inadequate for me to cycle the loads that I wanted. So I decided to take a closer look at my ports.

Upon Closer inspection I was able to see that multiple ports were mildly or up to half way occluded. by the gas block.


The port in blue has only maybe 5-10% of it covered. the ones in red are far worse looking however. the far one in the picture is maybe 30% covered and the one forward toward the camera is probably 40-50 % covered.


Being a Vepr I said "IMPOSSIBLE!!!!" and decided to drown myself in a bottle of Vodka because I was so distraught. when I awoke from my stupor I decided I needed to do something about this problem.


I began by stripping the shotgun down and getting out some tools.


Very important for the gas block pins is a solid surface to beat on the thing with. Any give in the surface is wasted energy that is not moving the pins. I used my garage floor and a piece of wood to support the gun covered with a towel. these are the punches i used to drive the pins out.








The pins should be driven out opposite the direction they were put in. you can tell because i believe the factory installs these with a press and you can see dimples on one side of the gas block. For mine they were installed right to left so they were driven out from the left to the right.





a few good blows with a hammer and the pins should knock loose.


After the Pins are out it is time to press the gas block off. For this I used my shop press and a pair of bars running across the base being supported by the hand guard retainer. Slide the bars as close to the barrel as possible and on even footing. The retainer actually worked out very well for this purpose. a brass washer is used to protect the crown of the barrel while pressing.






When you are pressing make sure everything is well supported and inline with the press ram. and remember SAFETY GLASSES!!!!


When you start pressing the press will load up and you might have a bit of a jump and then it will slide out smoothly. Or it should. Some are tighter on the barrel and some are a bit looser at least that is my experience with AK gas blocks.


Here is the result





This is what the gas ports looked like with the gas block off the ports all fit a 5/32 bit and there are no burs or anything. the red lines are slightly outside of where the shadow was but the camera makes it damn near impossible to tell.





Here are some pics of inside the gas block and how the mouth looks. When the factory drilled it at an angle they also drilled straight down through the witness hole on the bottom of the gas block this created two ears that were very rough and what mostly occluded the right side gas port. the back seemed to just be bad positioning.



I was very careful to not take much if any material off of the inside. I worked with a small sanding drum and removed only what was needed to uncover the affected ports. I then very slightly beveled the mouth of the window where it sits on the barrel without taking any material off of the inside edge.





after that was all done a quick job with the dremel to smooth up and polish a tiny bit of those marks out and it was ready to reinstall. Throw a very small amount of moly grease on the first contacting surface in a very thin layer. This stuff goes a long way. Note that you can barely see any of it? That is how little to use.




The next step is to line up the gas block and press it back on. DONT FORGET TO REPLACE THE HANDGUARD RETAINER!!!
Utilize whatever method suits you best to line it up. Some people use clocking rods (cleaning rods work well) I like to use that and the Mark 1 Mod 0 eyeball and I usually end up pretty much right on.
Once you get it lined up give it a few taps with a piece of wood and a hammer. You can use this method the whole way or you can switch over to the press but go slow and check frequently. Before you start pressing further double check alignment because it only gets harder to turn that gas block the farther down you get. Once its good press it on almost all the way. I like to leave it just shy of the goal and finish by hand with a block of wood and a few hammer taps.
And this is the finished product.
Hard to tell but the ports are unobstructed and the gasblock mouth fits around them nicely. Here are some pics of the gas block with ports reinstalled.
I hope this was helpful and good luck to anyone looking at this sort of thing. Test run tomorrow!!!



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Looking forward to the test and see how much of an improvement you have. I have seen several other posts where people were frustrated with their new VEPR not cycling the same ammo as someone elses would. I wonder how prevalent of an issue this really is.


I would also post this directly in the VEPR 12 forum section. I knkw we have some tool guys who could appreciate it.

Edited by menace667
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Good news today everyone. I think it may have done the trick. I was able to run a variety of different shells today through my shotgun today including some low velocity skeet loads and they all worked flawlessly with the factory Molot 5 rd magazine. I had 1 stovepipe with the SGM Factory 10 rd Vepr12 magazine from the Winchester Super Target 1200fps. Other than that the gun ran great. Ejection is still not as strong as I would like but it seems to be doing a decent job clearing the shells with the exception of that one round out of the SGM factory Vepr 12 10rder. I may do some more minor tweaking and polishing up things to see if I can get a bit more positive ejection with the lighter loads.


I ran:

Winchester Olin 2 3/4" Military Grade Buckshot




Remington Heavy Dove Loads 1 1/8oz @ 1255 fps




Winchester Super Target 1 1/8oz @ 1200




Remington Gun Club Target Loads 1 1/8oz @ 1145 fps





Here is a video I shot of the gun running some modified Saiga 12 Magazines. 1 is an AGP and the other is an SGM. both are 10 rds. the last shot on both magazines stovepiped for some reason. I am not exactly sure why. I suspect it may have something to do with the angle of the follower or the height of the follower in the magazine relative to the Vepr 12 followers with the bolt hold open tab.






Edited by Tommyid1
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