SKS Accurizing Thread...

grelmar

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So, earlier this summer, I picked up a minty SKS, a magwedge rail, and a scope, with the sole purpose of trying to build an "accurate" SKS. I got it all put together, managed to do a bit of plinking here and there with it, even took it on my summer road trip out to Vancouver Island. I was able to get a general sense of what it was capable of with different ammo, and where a couple of the "pain points" of the build were.

In the meantime, Ganderite started a thread on his accuracy results with his SKS, and I remembered "Oh, yah, I should head out to the range and actually put some dedicated time on this..." Thanks for reminding me Ganderite.

So, before I start to really work on getting this thing accurate, I went out today to get a bit of a baseline with 4 different types of ammo.

First, the rifle and range setup.

the_rig.jpg


An "undated" star on side of receiver SKS, so probably a late '55 early '56. This rifle may be a Polish Refurb, or maybe not... It's all matching #'s, and the bore is pristine. This is as good an SKS as I'm likely to be able to find nowadays. A good platform for an accuracy project, anyway.

The rifle is a Vomz Pilad (modern Russian manufacture) 1.4-6x scope, with great optics. The glass is as clear as my Leupold. The only downside to it is that it's heavy. Rather than use high tech material to make a strong cylinder, in typical Russian fashion, they made it stronger by making the metal in the tube thicker. It's a bit beefier/heavier than a more refined scope, but the price was great for the quality of the glass inside, so I was willing to put up with a bit of weight. The magnification range fits with how I'm going to use it "in the real world" as a Ranch Rifle/Deer Rifle.

For accuracy testing at the range, I'm using front and back bags from a shooting rest, to try and remove as much "shooter error" as possible from the equation.

I brought 4 different types of ammo with me today. Some Barnaul "mil-spec" non-corrosive FMJ, some 70's Czech Surplus, some 80's Chinese Surplus, and some Hornady Flextip SST rounds - which is what I'm zeroed with (ref: intended as a hunting rifle).

First up, 5 shot group of Barnaul:

barnaul.jpg


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Yah, in theory that's a 5 shot group. One missed the paper entirely, although I suspect it's that hole on the backing board high and to the left of the paper. The 4 shots on paper came in at roughly a 4&1/4" group, which is about on par with what my experience is with the Barnaul in this rifle and my other SKS with the open sights. Decent, but nothing to write home about.

Next up, 5 shot group of the Chinese surplus:

chinese.jpg


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Again, a "theoretical" 5 shot group. I'd forgotten this stuff shot a bit hotter than my other ammo, so the group was kind of high. I'm reasonably confident the missing shot was just above the paper, and that the 4 shots I'm measuring are actually a fair representation of what the overall group would be if I'd held just a bit lower, this time as close to a 4" group as doesn't matter. Realistically, on par with the Barnaul, and again within what I was expecting. No surprises here.

Round 3 - Bring on the Czech surplus!

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Spectacularly bad group, only 3 on paper. Totally what I'm used to with this ammo. It's early 70's production, and I have strong suspicions that the powder is starting to degrade. I've gone through about 800 rounds of this stuff, and it's just miserable ammo. You can literally hear the difference in the pop from shot to shot. It's dirty as heck, black sooty crud throughout the barrel and gas system. The three shots that managed to connect with paper show a 4&1/2" group... Realistically? Double that for a 5 shot group. The Czech ammo has a decent rep, but I'm pretty sure I got a cruddy case of it.

And finally, an actual 5 shot group on paper with the Hornady SST ammo:

hornady.jpg


hornady_m.jpg


There we go. Right close to a 3" group, and that's about what I was expecting from results I've gotten with it from both my open sight SKS and from informal plinking/zeroing with this rifle setup. I haven't run a ton of this ammo (most expensive of the bunch by far), but it generally outperforms the others. Both my SKS's seem to like it, and that's a good thing because it's what I'm hoping to bag a White Tail with next month (if I can get the time off work to actually make it out hunting this year - still a bit up in the air).

For now, this is what I'm going to use as my benchmark ammo as I move forward on "accurizing" my SKS.

I know, I know. I should have shot/recorded more groups for a more empirical test. I actually shot a 10 shot group of the Hornady, and it came in at just over 4", but there are a couple reasons why I didn't take it further.

#1 - My goal today was to see which ammo I was going to use for a benchmark. Between previous experiences, and what I measured today, I'm fairly confident that the SST ammo is the way to go.

#2 - I started to get the sense that my Zero was wandering a bit. You'll note that the Hornady group was hitting to the left of what the 3 other groups were hitting. Vertical stringing could be just about anything. But a right-left drift made me check my scope/mount setup, and I quickly noticed something wasn't quite right.

If I grabbed the scope and pushed on it up and down, it seemed fine, but left to right, there was a slight movement at the front of the MagWedge rail where it fits into the rear sight base. When I got it home and started taking it down for cleaning, it became bleedingly obvious that yes, the front of the magwedge rail was ever so slightly narrower than the channel of the sight base. Over the course of shooting, it was drifting back and forth just enough to throw my left/right zero.

Which lead to part 1 of my accurizing: shimming the front of the Magwedge rail.

I cut a couple of narrow strips of tinfoil from a Chinese Delivery tray (a million and one uses - pan to keep random parts in while you're working in the garage, drip tray for chemicals, nice target for shotgun patterns, and now a handy source of tin for making shims). I took the two strips, layed them on top of each other (engineering guesstimate as to the thickness I'd need), formed them into a U shape and tucked them around the front of the MagWedge rail (which I'd removed) as I slotted it back in. I used an ardox finishing nail to punch a hole clear through, and hold everything in place while I tapped the roll pin back in, displacing the nail as I went. Then trimmed off the excess tin so it looked relatively clean (if you stood back and squinted).

The pictures explain it better than my words:

shims_1.jpg


shims_2.jpg


shims_3.jpg


shims_4.jpg

(note about the last picture: the angle hides the shim on the other side, but they do form a U all the way around).

Once I got everything back together, and tried to get the front to move around again. It felt way tighter than it did before, although there might be room for one more layer in the tinfoil. I'm going to leave it as is for now, and possibly think of some other method of tightening up the front of the rail.

The other modification I made tonight was to remove the bayonet. It took a bit of oomph to crack the seal on screw holding the bayonet on, but I managed to do it smoothly without damaging the head of the screw, its threads, or the bayonet itself.

Why would I take off the bayonet? Because it moves. There's no way that leaving it on is going to help anything, and there's a decent chance removing the weighted rattle from the front of the barrel will actually help things out.

Also, if the Deer charge, I doubt I'll be fast enough to get it flicked into place to save myself. :p

And here it sits, in the configuration I like to call "Stage 2" (because I'm creative like that) :

stage_2.jpg


I have a few ideas of a couple other things I can do to tighten things up a bit more, and squeeze a bit more accuracy out of it. #1 is the rear retaining bolt/pin for the rail. I'm not 100% satisfied with it - it has a tendency to start to work loose after 50 shots or so. I have the "quick pin" from Magwedge, but that isn't going to improve things - just make it easier to take down. I have an improved design in mind, but I'm not sure if my machinist friend is into me for favours or the other way around (probably the other way around).

#2 is to bed and pillar the receiver. So far, nothing I've done falls into the category of permanent modification. I've kept every part I've taken off, and can put it back to stock configuration at any time. If I pillar and bed the receiver, it will be a permanent mod, and I'm not sure how much I want to do that. I might end up just shimming it, or maybe "soft" bedding it with layers of wax paper to tighten the fit without making a permanent change.

#3 is to detail sand the inside of the forend. I'm not sure how much this might gain me, but using a bit of fine grit sandpaper to polish up the barrel channel is a permanent mod I'm willing to make.

At some point, once I've got everything done, I'll collect up everything I've posted about the project and put it on my personal blog, so that the whole world can laugh at my foolishness. For now, I'll keep things in this thread so that the nutters get a first chance at poking fun of this whole crazy idea of making an accurate SKS.
 
Some things to consider... This was a military infantry rifle designed to pretty much hit a pie plate. Accuracy depends on your expectations from a military semiautomatic. Getting it to be as accurate as a bolt action sniper rifle would be next to impossible. Your head space in the chamber needs to be checked and the factory barrels aren't the best. Nobody would ever laugh a project, we all are obsessive!

However, your SKS will always not be about accuracy but the fun of putting as much lead down range as it can handle! Update us how you make out.
 
Some things to consider... This was a military infantry rifle designed to pretty much hit a pie plate. Accuracy depends on your expectations from a military semiautomatic. Getting it to be as accurate as a bolt action sniper rifle would be next to impossible. Your head space in the chamber needs to be checked and the factory barrels aren't the best. Nobody would ever laugh a project, we all are obsessive!

However, your SKS will always not be about accuracy but the fun of putting as much lead down range as it can handle! Update us how you make out.

Oh, I'm very well aware of the design intent and limitations of the platform. One of the big things working against it is actually the tilt-lock bolt, which is known for causing accuracy issues. And the barrel itself has a fair bit of whip to it. There will only be so far I can take it.

But that just adds to the challenge.

One of the things that's really working against accuracy is something that can, in theory, be easily controlled for. And that's ammo. Bulk surplus ammo is what it is, and has serious consistency limitations. Bulk commercial ammo (ie: Barnaul) really isn't much better. If you look at the guys doing serious accuracy work on any platform, they either spend big $$ on match ammo, or roll their own. That alone makes a huge difference in just about any rifle.

Oh, and the receiver is slopilly bedded... That's an accuracy killer right there. That isn't so much a design limitation as it is a production limitation. They pumped these out in such quantity, that they built in a pretty wide tolerance for the bedding of the action when the stocks were fabbed up. Remove the trigger pack from pretty much any SKS, grab the barrel and the rear of the stock, and start pushing it back and forth. Invariably, there will be a very noticeable play. Tightening that up should help a great deal.

And the stock iron sights are mediocre at best - and that really doesn't help. Especially with eyes that have 40+ years of mileage behind them. Which is why the first thing I did was to go with some optics and a decent mounting option.

Will it ever be a 1 MOA tack driver? Nope. But with a bit of work and the right ammo, I think I should be able to get to 2 MOA.

Out of the box, up against a full sized IPSC silhouette target, an SKS will do "minute of bad guy" out to 200 yards with almost any ammo. I've played around with my other SKS trying just that, and it's fairly easy to hit with stock sights and no mods. Which speaks well of the design of the platform - it really does what it was intended to do, and does it well.

This whole project isn't just about accurizing, it's about establishing what can, and can't, be done with the SKS to make it a more accurate shooter.
 
One thin i would keep in mind is its quite posible to get a good trigger out of it but it may result in reliability issues. At most i would suggestonly polishing the contact points. It would also be interesting to see if removing the while front sight/ bayonet lug assembly would have any effect on accuracy.

Good luck with your project.
 
You seem to have some realistic expectations on the level of accuracy achievable with the SKS and are working on the big things that affect accuracy.
Keep us updated on your progress.
 
Shimming at the very rear of the of the rifle to push it forward into the stock works very well. I have done nothing else to my SKS and am happy with the results I am getting with Czech surplus and iron sights. I haven't shot it for groups but ring 8x8 inch gongs at 100m quite consistantly.

My SKS had a lot of play, at least 1/8 inch back and forth. IMO shimming up and removing this play is the easiest way to get your SKS shooting better.
 
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