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Confirmed... Optic Rail Not Useless after all! <edit>


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Well all this time I've been swapping hammers, springs, re-profiling and polishing parts (still haven't done the bolt & carrier yet because I wanted to make it run on low brass first...) and trying to figure out why the damn thing still would not cycle even the Federal 100 rd value pack stuff, much less that Winchester Universal crapola...

So today just for the hell of it I removed my red dot holo sight from the top rail and BAM.... she cycled like a friggin wet dream. Put it back on again and jammed / stovepiped / munched every round. Took it off again and emptied a whole mag with hulls ejecting 6 feet out at 2 o'clock. What is the damn point of having the rail if you can't clamp anything down on it?? Gonna go out and give it another try with my Kobra next. Maybe a Russian gun just refuses to run with a Chinese Sight Mark optic on it... I dunno. Will soon find out though. I even tried moving it back to the rear end of the rail... same thing.. Jam Jam Jam.... WTF

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Well back from the range and it's definitely confirmed on my V-12 anyway, that it's prejudice and prefers Russian Optics...lol. At least the rail isn't useless.... smile.png

I went ahead first and put my custom FCG back in there, replacing the factory one I had tried going back to to see if that was the problem. With my reprofiled & polished FCG it ran like a scalded dog on the Winchester Universal crap, the Federal even better, and even this Estate stuff a buddy came over with last week that won't run in his S-12. It was so weak in the S-12 (with four ports and my bolt and trigger work...) it was shoving this Estate #9 shot right back in the pipe. But his gun ran fine on the Federal Multi Purpose 1200 FPS. Well the Vepr ate that stuff like candy and ejected great. So I put the Kobra sight on the rail, which is the clamp on pic rail type, very similar to how the Sight Mark clamps on, with side bars and a throw lever. Did awesome with everything with the Kobra. Put the Sight Mark on it again and same ol shit.... Jam O Matic. Well I guess I know which red dot to use on her now at least, and which one NOT to use except on a different gun. So strange....

 

This is the model Sight Mark I have....

http://www.sightmark.com/products/reflex-sights/ultra-shot-qd-digital-switch-sm14000

 

And this is the Kobra. Mine is like the one on the right with the throw lever style attachment base.

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You have to use a smaller optic and mount it at the rear of the rail as far back to your eye as possible. The round ejects out and up, clipping the edge of the site. There are slow mo vids on youtube detailing this. Several posts about it out there.

 

 

The sight ark should work if you mount it at the very rear of the rail.

Edited by ny5093@yahoo.com
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Here in Russia we do not use the Cobra.Any sight to put closer to the eye, otherwise there will be problems. This is well known.In the video, visible path departure sleeve

http://www.youtube.com/watch?feature=player_embedded&v=GJ8AF3kk2oE

 

In the photo shown by the arrow marks of departing liners 87097079.jpg

 

 

Sorry for my english smile.png

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It's that damned first long rivet, and I'm still not convinced that neither the VEPR 12 nor the Saiga 12 030 needs it. It's the culprit to causing bolt carrier rubbing friction, i.e. slowing down the cycling speed and rate of the carrier. I have asked this before but received NO answer... Will the CSS aluminum rail or the Performance guide rod allow us to run our gun without the first long rivet?

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I am very curious about this as well. Cobra reports moving the optic from front to back and still having the issue. If interfering with ejection is not possibly the cause cobra based on the positions you tried, let us know.

 

If this is a weight issue, I wonder. if not either of those, what is it?

 

I have replaced the rail on mine with the CSS but haven't been out to do any shooting since. I have an Eotech on mine. All the way to the rear, as I read about the ejection issues when PapaZ pointed them out.

Edited by ec4321
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It's that damned first long rivet, and I'm still not convinced that neither the VEPR 12 nor the Saiga 12 030 needs it. It's the culprit to causing bolt carrier rubbing friction, i.e. slowing down the cycling speed and rate of the carrier. I have asked this before but received NO answer... Will the CSS aluminum rail or the Performance guide rod allow us to run our gun without the first long rivet?

The front rivet must be longer than the other rivets. Velocity of the bolt carrier, it does not reduce.

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Thank you for that video Sergii! The way the hulls are bouncing off the charging handle and slingshotting forward / out makes me wonder if possibly some modifications could be made to the ejector to fling them more outward than back... Or if nothing else make some kind of deflector to keep them off the optic... similar to the SKS shell deflectors.

 

Sergii I am interested in why you guys don't like to use the Kobra sight. They used to be very popular. I have three different ones and like them all. Only complaint I have is on my weaver mount one I have on the Vepr right now, the power switch broke and I need a replacement. Other than that they have all been great to me.

 

First thing I did when I discovered this problem in my gun was to examine the top of the carrier, and the rivets inside the cover. I could definitely see where it's rubbing, but it just didn't look all that bad. Any rubbing at all though is not good, so now that I've confirmed it definitely IS a problem, I'm going to grind that front rivet way down and polish it as well. I don't see why it needs to be over twice as big and thick as the others. I'm going to polish the top of my bolt carrier as well. Additionally I can see where the extra dust shield on the recoil spring, is chafing the side of the carrier. I'm going to polish the inside and leading edge of that as well.

 

As far as moving the optic all the way to the rear... I said I did that but actually since I didn't have an allen wrench the right size with me that day, I could only move it back as far as I've demonstrated in the last pic here. I have a TWS peep sight mounted there so it keeps the red dot from going all the way back. It's great for doubling my sight radius with irons, but just to see I'm gonna remove it today and try again with the Sight Mark mounted all the way back, and see if that does it. It probably will because now it's got my FCG back in there causing less friction, and I'm sure the rest of the mods I have planned will help it even more. It was already borderline last night when I tested it after putting my FCG in again. It would cycle with the muzzle pointed straight up, using gravity to help, but still not horizontal.

I'll test with the sight moved all the way back before grinding and polishing anything, just to maybe help someone else.

 

Pics of what I have...

 

You can see in #1 where the paint is rubbed off the carrier and the front rivet.

#2 shows the scraping on the side.

#3 & 4 shows optics and placement. I did have the Sight Mark all the way to the front where I would prefer it to be. I really hope to get it working because I really do like the sight actually, and I still need that power switch to get my Kobra back up & running. Right now it just wears that smiley face to fuck with me I think...lol.


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Sergii I am interested in why you guys don't like to use the Kobra sight. They used to be very popular. I have three different ones and like them all. Only complaint I have is on my weaver mount one I have on the Vepr right now, the power switch broke and I need a replacement. Other than that they have all been great to me.

Contact "Tantal" on theakforum. He may still have some replacement switches for sale.

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Eek, i second the dont do it. Unfortunately papazorro was banned and censored from this forum, but he explained it well, the front rivet is thicker, because it is a guide to keep the carrier aligned with the slot in the gas puck, without it you are sorta just tossing the bolt carrier in the general direction of the tiny recess it needs to fit inside of. I dont see this working out well.

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The longer front rivet isn't needed to align the oprod with the gas puck. You can see this for yourself by firing the gun with the cover open. The swelled part of the end of the oprod, right before the thinner section that interfaces with the gas puck, maintains the oprod's alignment by riding inside of the gas tube. Ever wonder why those star-shaped indentions are pressed into AK gas tubes? Now you know. :) You can see the wear marks if you examine your oprod.

 

I think the purpose of the long rivet is to force the top cover back to its top most position on each shot, since it has some vertical play in it.

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The longer front rivet isn't needed to align the oprod with the gas puck. You can see this for yourself by firing the gun with the cover open. The swelled part of the end of the oprod, right before the thinner section that interfaces with the gas puck, maintains the oprod's alignment by riding inside of the gas tube. Ever wonder why those star-shaped indentions are pressed into AK gas tubes? Now you know. smile.png You can see the wear marks if you examine your oprod.

 

I think the purpose of the long rivet is to force the top cover back to its top most position on each shot, since it has some vertical play in it.

 

 

I find the rivet interesting. One question is - if it is needed, why don't Saigas have them?

 

BUT - I will say this. On my vepr, with the cover open the carrier can be pushed up further than it can with the cover down and the rivet preventing the travel. Try it yourself. If that is important or not is a matter of debate.

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That front rivet is long by design, I wouldn't go messing with it. It keeps the bolt carrier from moving upwards and I imagine helps prevent breakage from possible deflection.

 

Rivet prevents excessive movement of the bolt up. This reduces the chance of breakage bolt carrier.

Edited by Sergii
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@ec4321

 

Did CSS use a longer bolt where the front rivet went for their rail?

 

The kit came with one screw that had a bigger head than the other two. The head wasn't as big as the original rivet, however, if I recall.

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Well thanks for everyone's input on the larger front rivet. Instead of grinding it down I'm just going to polish it smooth, along with the carrier where the paint is being rubbed off. Between that and polishing the dust shield on the return spring, and the re-profile and polishing of the bolt, carrier, and FCG, I'm fairly confident that will be enough to let me run about everything in it, including Winchester Universals. I don't like shooting that stuff because it's so inconsistent, but it's about the only thing I can ever find any more at my local Walmart, when they have anything at all.

I went down yesterday and put a whole box of them through it, along with some Federal Multi Purpose (bulk pack) Loads, and some of that Estate #9 shot that wouldn't cycle good in my buddy's S-12. First I tried moving the optic to the rear, which worked like a charm and cycled everything. Then tried again with it moved to the center of the rail. In that position it will cycle the Federal, but still not the other loads. Moved it back to the front again and got the same failures with everything. Tried switching to the Kobra again and it worked great again. Then tried a BSA red dot up front..... no good with Winchester, but it will cycle the Federal with it there. Same results from switching to this Eotech knockoff sight I have. My conclusion is it must be the actual weight of the optic, keeping the dust cover from being able to flex upward as the carrier rubs across the rivet. Something small like the Burris Fast Fire or Docter would prolly be alright at the front.

I then swapped out the forward recoil spring with a Wolf 8 lb replacement spring for a 1911. This allowed me to shoot the Winchester and everything without any problems as long as I kept the sight anywhere from the center position back. Just that small change was enough to make the difference. It even allowed me to cycle the Federal with it all the way up front, but only that with the Sight Mark. The light spring didn't help with the Winchester and front rail setting. I think it will prolly work though after I polish the rivet, and re-profile / polish the bolt & carrier the same as I do my S-12s. We'll find out soon on that.

 

A few pics... I'm actually liking the sight ok now in the middle of the rail, and it's already doing fine there with the 8 lb spring. Also after seeing how much shock is being transferred to the rail up there in front, I'd rather not try to put a sight there. I'm hoping after the work I'm getting ready to do, I can put the factory spring back in and be GTG!

 

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Must be another wide variance in spec issue from the russians.

 

I had a Eotech on my vepr, almost all the way to the rear, and did not have a single feed issue with it setup like that (did a shit load of shooting with it too). The Eotech will go back on, but the vepr is away being chopped and perm attached brake.


I will, of course, do more shooting like this and I hope to have no issues but the chop and perm and going to change other dynamics as well. We'll see.

Edited by ec4321
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Just off the top of my had; and I have not messed with the insides. I don't know if the length is available. But an idea.

 

If you could replace the front long rivet with a screw. Put the screw in from the outside. Threading the hole in the cover would be a nice idea. Get a piece of Teflon thick enough to cover the screw and hold the bolt carrier in place. Drill an undersized hole in the Teflon and screw it on to act as the nut while reaching far enough to hold the bolt carrier in place like the current rivet does. Or adjust the height of the cover; whichever it is there for. Probably put a good lockwasher under it. If you can do that, it should reduce the wear on the bolt carrier and not add nearly as much friction. You could extend the idea and put a piece of shaped Teflon in there with maybe an extra screw or two to make a real solid piece. You might want to make a couple of them so you have a replacement if one wears out.

 

Perhaps some Loctite on the screw/carrier hole. On the Teflon it won't help. Or some variation. If you have room, you could machine a piece of Teflon to span the whole cover area and perhaps be able to provide more robust retention.

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I would still like to know from our Russian comrades Sergii and Papa, (yeah I know NM) just why the Vepr needs that extra "support" of a rivet keeping it down so it can hit the mark. As has already been said and I do believe... the reason for the fluted gas tube is to keep the gas piston aligned. Why does the Vepr 12 bolt carrier even need that 'mother's little helper' to get it to cycle rounds like a true AK that has no such rivet?

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Alright y'all I just figured out the real purpose of the offensive rivet head...

 

It's only there to try and help that piece of crap, half ass LRBHO design that still only half works. Lift your dust cover, take out your recoil spring, and run your bolt & carrier back and forth on the rails.... with an empty mag inserted. The bolt glides right over the top of the BHO stop. It won't even touch it unless you press down on the carrier while pushing it forward.

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