Shim SKS Stock

mosinmaster

mosinmaster

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Hi,

Just wondering if there's a sticky or somebody with know how on how to shim the sks stock so it wobbles less at the front ferrule. My laminated stock has dried up in storage and there's a bit of wiggle at the front. After seeing Riflechair's video on bedding his SKS and getting 2" groups at 100m consistently, I want to try a non-permanent fix and see if it works, and if it does for my rifle, then go to bedding.

Cheers,

MM
 
1. Remove the trigger group (remember to have the safety "on" -up against the stock) 2. insert a shim between the rear of the receiver and the stock.
This will push the receiver forward, tightening everything up. Not as good as bedding, but close enough. Shaves a couple of inches off my groups.
 
Do you mean where the spring is in this picture?
P1010094.jpg


Or on the rear inlet like this Mosin
July2010catscarsandlawnmowersM39051.jpg
 
Thanks for the clarification! Any recommendations on material? leather, waxed cloth, cut up aluminum pop can, cut up credit cards?
 
mosinmaster said:
Thanks for the clarification! Any recommendations on material? leather, waxed cloth, cut up aluminum pop can, cut up credit cards?
Click to expand...

Something stiff that can be driven in, would be good. It looks like you might need a shim that is quarter of an inch thick! Got a popsicle stick? Or any wooden wedge.
 
How much of a shrink in group size did you see? Were you using surplus? My rifle in stock configuration shoots all over the paper target at 100 meters, but somehow shoots a tight group with touching holes at 25 meters.
 
mosinmaster said:
How much of a shrink in group size did you see? Were you using surplus? My rifle in stock configuration shoots all over the paper target at 100 meters, but somehow shoots a tight group with touching holes at 25 meters.
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Shiming usually shrinks my 100m groups from 8inches down to 6 inches with surplus ammo and "as issued" SKS. Some of my SKS do a little better, some do
much worse. I wonder if your excellent 25m results might have to do with your being able to see the bullseye and "aiming small" as a result?
 
I bought an SKS in a timbersmith stock recently that had a bit of forward backward play and some wiggle, so I put a bit of work into the bedding. Maybe too much, I got a bit carried away honestly. This was the solution I came up with rather than shimming.

I used some marine epoxy to bed the rear of the action, and the draws area at the front of the action where the trigger group hinges into. I also bedded the crossbolt so it's very firmly fit against the action. There is now ZERO wiggle in any direction. And to take it the extra Mile I put some bedding under the ferrule where it holds the tip of the stock.
Lastly, my handguard was contacting on one side and not the other so I sanded the side making contact down so both sides were free floated. At that point it had some wiggle so I used automotive grade RTV silicone to bed the top handguard. I figure the silicone would be better than epoxy in that application as it will be more dampening of any contact between the stock and handguard when the gun is firing. And it feels super tight. Overall this thing feels rock solid now. I'm optimistic it'll shoot better than the last time I took it out. Which wasn't all that bad either.

Is this overthinking an sks? Maybe. So what, I bought it in this stock so I may as well have some fun tinkering with it.













 
The most complicated part of bedding the SKS seems to be the front barrel band thingy... Cus nobody for certain seems to know what to do there... What produces the best barrel harmonics? Some think it's having the stock to barrel fit very tight, others think having partial contact is better with a cork tensioner on the barrel somewhere, other think a total free float is best.... Idk
 
warrenlikesboats said:
The most complicated part of bedding the SKS seems to be the front barrel band thingy... Cus nobody for certain seems to know what to do there... What produces the best barrel harmonics? Some think it's having the stock to barrel fit very tight, others think having partial contact is better with a cork tensioner on the barrel somewhere, other think a total free float is best.... Idk
Click to expand...

That's something I put a lot of thought into and had to come up with my own theories as like you said, there doesn't seem to be any consensus about what works best there that I could find online.

My thought is it can go either way. You could keep it so that the tip of the stock is free floating inside the ferrule so as not to impart any harmonics. Or you can go the other way by reinforcing the tip in the ferrule, which personally is the way I went. And I'll tell you why.
First I can see the potential for a free floated stock tip to "rattle" inside the ferrule when the gun is fired, which doesn't sit well with me. Second I feel that thin barrels typically benefit from some form of support or pressure at that point anyway. But it should be done in conjunction with handguard bedding so it dampens barrel flex in all 4 directions, not just upward flex.
Think of the barrel firing in slo-motion, with the barrel moving up and down after the shots fired. By bedding the ferrule you restrict upward and to some extent, sideways movement of the barrel, and by bedding the handguard you restrict (or dampen in my case using silicone) downward movement of the barrel by way of the gas tube retaining mechanism. Assuming the handguard is bedded to both the gas tube ferrules and the lower forestock.
 
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Yah im thinking more or less the same thing, when I make my custom stock, im just going to make everything tight.... and then see what the accuracy is, if its poor, then maybe ill try playing with the harmonics a bit. Tony Ben (i think is his name) one of the big M1A dudes on CGN did an interesting video on bedding an M1A stock. For the front end, he suggested placing a cork pressure point on the barrel mid length and hooking the front ferrule on the stock bedded with some downward pressure. I wonder if that would work for the SKS as well.
 
That will be my next experiment after testing this. I'll probably apply a 4-5 lb pressure bed in the ferrule. But I'll have to re-bed the handguard so it doesn't put pressure on the gas system.
I also splurged and picked up some Hornady SST's to try in this thing. Hard to tell how accurate it is with mediocre ammo. But I'll still test its groups with the Barnaul too and see how it compares to the last time I shot it.
 
Check out this AGI SKS Armourer's course for the bedding and accurizing. He explains the stock ferrule and places to glass bed.

 
No he actually goes into in depth discussions on the weapons design. I.e. the gas block is at an ideal distance for reliability because at that distance from the chamber the gas levels are uniform. Any closer would be variable due to high or low pressure curves in ammo variances. At the gas block, the gas pressure is past the curve and is dependent on the amount of powder burnt rather than a peak or trough in the pressure curve. He also goes into detail regarding the chamber cut and 7.62x39 cartridge taper (fitting a peg into a cone = reliable). He also says the extractor (beefy) combined with the ejector that is an integral part of the receiver are ultra reliable. He then spends a lot of time talking about the safety mechanism of the tilting breech block design as well as the trigger assembly safeties.
 
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