SKS accuracy question?

Holleyman said:
I have my Norc scoped with a Choate drilled mount and a Leapers scope, a pinned compensator, Choate synthetic stock and some minor trigger rail polishing. This rifle will shoot 4-5" at 100 yards. By no means a "tack driver" but using surplus ammo I am very pleased with it for the money!
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My sentiments exactly! Don't get me wrong guys, I'm not questioning the benefits of bedding the action of an SKS and I think it's an extremely beneficial exercise, but at the end of the day as long as every round hits paper I'm happy :D Plus, it makes lots of noise!! Weeeee!!
 
Mike, the SKS does not have any support in the front portion of the barrel. there is no 'recoil lug' per se.

So that barrel has an extremely long lever arm on the back of the action. Throw in the movement of the gas piston and you set up for inconsistent barrel vibrations.

Like the M1A/M305, locking them tight in the stock yields significant benefits.

Is it likely that a stock will warp under heat? Is the barrel heat up enough to cause it to warp the stock?

I am going to say no. By the time any barrel gets that hot, it would have fired enough rds that accuracy would be joke. Might even have melted the epoxy but that's another matter.

Locking the barrel tight in the stock helps to stablize the bending of the barrel during recoil too.

If anyone has a chance, take a chamber cast of their rifle. I did and was horrified at how lousy it was. Basically, no throat for quite a long ways. With this style of chamber, the rifle is designed to spray bullets. Add in that surplus ammo is not match grade, and you get the accuracy we see.

I wonder how many SKS have chambers cut that way? Also, what would happen if a proper chamber was cut? Would it shoot as well as a M305?
Jerry
 
My gun goes bang every time now and hits the paper . good enough for me .
But this is such a cheap gun I just can't help to screw with it . Ever change a cam or intake just 'cause ? same kinda thing .
So Mysticplayer , you say ( if I get this right ) to bed the barrel in the lower stock as solid ( tight ) as I can ( I know , still removeable - but totally supported ) . This should help in accuracy over a " freefloated barrel " .
I'll shoot it this weekend unsupported and see the results , then next week I'll goo the living sh*t out of it and see how it does . JB to the rescue .lol
I'm going to screw with this thing until I screw it up or until I run out of ideas , I just can't help myself .
 
When bedding the front ferrul/barrel band, ensure that the barrel cannot move in ANY direction including forward.

An sks can move forward if the recoil cross pin is not a perfect fit to the action. I had a bolt through the cleaning rod hole to hold the front end in place.

It only takes a few thou of movement to cause irratic accuracy. The goal is a 'fully bedded' stock or in another way, an action/barrel that cannot move in the stock in any direction even when some very strong tugging is involved.

There is no way to stop the receiver cover and gas system/handguard from moving so that creates a variable to live with. From here, working up a load might just produce exciting results.

Also, use a sighting system that also doesn't have any slop. The orig open sites can and will move around. Most receiver scope mounts have play. Bolting a scope base to the receiver like the Choate, PSOP style or the mounts I can offer is the only way to eliminate any play in sighting.

If the barrel has a decent chamber, fed better bullets, it should shoot around 2MOA. Maybe better.

I don't think freefloating barrels in these types of rifles will work. Too many things hanging off it moving around at great rates of speed. Then they crash and clang at either end of the firing cycle.

Recent articles I have seen on the Sage M1A stocks illustrate the same problems (barrels are supposed to be free floated in these stocks). The accuracy results of these rifles was very poor. Certainly no better then an off the rack untuned GI M1A.

Jerry
 
The above is against all I know of bedding (very little). I thought that bedding means firm contact of the receiver with wood and no contact of barrel with wood anywhere in front of the crossbolt. A piece of paper should move freely between wood and barrel.
 
There are two methods for bedding. The most common is action bedded with barrel mostly or all free floated. The other is fully bedded. Some will also add pressure under the barrel at the front of the stock (pressure bedding).

All this applies to bolt actions where there are no moving parts during recoil.

A full stocked military rifle or commercial semis based on this military design is installed using a front ferrul and a locking mechanism (usually the trigger group) at the rear. The rifle is unsupported between these two points (except maybe a cross bolt). Add in the fact that nothing is well fitted, and you have alot of slop which affects accuracy.

Some companies in the US build M1 and M1A receivers where a lug is put in the front and possibly the rear of the receiver. This allows that rifle to be bolted to the stock just like a bolt action rifle.

In this case, the barrel can freefloat as there is support to help the receiver carry the barrel weight.

Unfortunately, there are lots of moving parts smashing and crashing about during recoil. If the recoil cycle is timed right, the bullet could be almost or out of the barrel before all this movement happens. Most of the time, something is starting to move before the bullet leaves.

By locking the entire rifle, except the 'pistol length' barrel, you are trying to eliminate these affects on barrel harmonics. If it can't vibrate the same everytime, make sure it can't vibrate at all.

The exception to all this is the AR. There are no parts moving to initiate the recoil cycle (gas impinged). Great for accuracy, problematic for fouling. Will be interesting to see how the new gas piston rifles compare. Will they have the same accuracy potential or share the same problems as other gas piston semi's?

Jerry
 
Ok, Jerry

Your idea is sold:) ....it will be a great project for this weekend....

Here is another interesting observation about the moving parts in SKS. I was trying to find a way to protect environment;) so I removed gas piston to change the SKS into a bolt action....then all in a sudden the hit point moved down 6" at 50 yards....and when I put the piston back, the hit point moved back (Note: I can be wrong, it mabe the other way around)....Can't figure out why.....:confused: ...it's ao consisitant....

Michael
 
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Took my SKS out on Sunday and put some rounds down range .:)
Still goes bang every time , no FTF anymore .:D
The bolting together thing has definately helped . It used to have two fliers out of five but they have been pulled in considerably . One weird thing though , the rifle sounds different now . I don't know if thats good or bad but its the most accurate its ever been .
I'm almost thinking of putting on a posp scope as I think my eyes are now the limiting factor . :eek:
 
RUPZUK said:
Took my SKS out on Sunday and put some rounds down range .:)
Still goes bang every time , no FTF anymore .:D
The bolting together thing has definately helped . It used to have two fliers out of five but they have been pulled in considerably . One weird thing though , the rifle sounds different now . I don't know if thats good or bad but its the most accurate its ever been .
I'm almost thinking of putting on a posp scope as I think my eyes are now the limiting factor . :eek:
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Looks like you had some positive results....

Mine is another story.....I fixed barrel into stock but didn't see any improvement....:eek:
 
Steiner said:
Would the synthetic aftermarket stocks help improve accuracy? Are the synthetic stocks a snugger fit?
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My butler creek stock has a relief at the rear that matches the rear lug and a bulkhead that slips in front of the front ferrule. It's definetely tight, when I pop out the trigger group everything, including the reciever/barrel, goes "sproing!"

I have also been told that synthetic stocks are made with a certain amount of "banana" in them, ie; curve against the shape of the reciever & action, to provide spring force to hold everything in place during firing. I can't really tell when I look at mine, but the amount of banana may be less than 1/8", which would be tough to see on an irregular shape like a stock.

All I know is that my SKS out of the box shot horribly. Spray and pray. I can hit beer bottles 3 out of 4 times at 70-ish yards now with the synthetic stock on (open sights). It did make a difference in accuracy.
 
loose tolerance=reliability

The SKS was designed for loose tolerances in its parts which is what makes it THE MOST RELIABLE AUSSAULT RIFLE, even more so than the vaunted AK. But this does not lend itself to great accuracy, The sight s are also hard to see, with mine I get 1-2" groups offhand at 25yds, at a 100yds from the bench a 8" group is about all I can do with the open sights. I think Ill put a 4x compact scope on it and see how much of a difference that makes. I bet it will shrink it in half.
 
RUPZUK said:
I'm almost thinking of putting on a posp scope as I think my eyes are now the limiting factor . :eek:
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Us the proper Russian built scopes, as they are tuned to the ammo you are using, also you will be using the proper side mount for these rifles, and not those stupid loose as a Gooses a$$ receiver cover scope mounts.

I think SKSman has some, among others.
 
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