Dear Bob:
I've had some interesting experiences with my Yugo SKS I'd like to share.
By the way, I'm pretty sure my Yugo SKS was unfired like you said yours was.
I've had cycling problems during the first (post cosmolene removal) box of Russian rounds which I believe I then cured via enlarging the barrel by-pass hole to a diameter half way toward that of a Norinco SKS I used to have. FYI, the by-pass hole diameter in my Romanian AD-47 is REALLY LARGE, way larger than that Norinco SKS's. I can give you the drill sizes/hole diameters I'm talking about if you wish.
During the next 40 rounds or so, my firing pin stuck due to the metal forward of the fp retaining pin, metal on the fp itself, literally plowing up (upsetting) and locking the fp hard in a position of lightly denting some or most primers. I found this was not a dirt fouling issue, rather actual upset/shearing forward of the fp metal, thus dragging on the passage way in which the fp fits. One would think the fp would be very hard, and would dent the retainer, but no. I easily filed away the upset metal on the fp with a regular file, but I've not used that original fp since. It's a wonder the SKS didn't go auto on me as the fp tip was protruding out of the bolt about as far as a regular fire-travel. The gun actually fired singly, after reloading the lightly dented round. Sometimes I'd only get a "click" though. I had to drive the fp out of the bolt with a drift punch with pretty good hammer effort.
Thanks to you and Brownells, I now have a Murray fp and it works well. However, I'm not thrilled with the shape of the Murray unit, as I feel the original fp design has a broader tip, other than the possible hardness issue that caused the metal upset problem. I'm not convinced Murray's spring idea is needed or worth the trouble. AK's don't have a spring, nor did my well-working Norinco SKS.
To go on, again, now I'm getting that primer-punching protruding metal ring on the bolt face I read about. I've filed that down (with another diamond file), but now wonder if the Yugo people didn't heat treat the bolt correctly. It seems to rebuild itself in about 40 rounds of fire. I believe the bullet bases are actually extruding the folt face. And, maybe Murrany's fp design is contributing. I'll be looking for another bolt at gun shows, or trying one from Numerich or someplace. Maybe the new one will be from another country and be harder. I believe all SKS bolts, whatever the country of origin, are the same design and size.
Lastly, I installed a 30-round magazine which works very well. It is a "USA Mag" unit, which, contrary to your comment, DOES hold the bolt open nicely when empty. What make did you try?
Interestingly enough, none of my AK mags held the bolt open until I found a Yugo AK mag. which does. As a sidelight, somebody showed my how to modify non-holding mags via disassemble and reworking to hold a bolt open.
That's all for now.
I'd like to hear if you got this note and if you think I'm on the right track with any of my Yugo SKS comments, etc.
Ps, my next move is to try a buffer. Numerich has them for $9.95, but I'll look at gun shows first. Think I'll get one for my AK, and maybe my Smith and Wesson .22 caliber model 41 target pistol too.
Don of Milford (Cincinnati) Ohio.
6 comments:
Don, thanks very much for the letter. I'm not a gunsmith, so I'm not qualified to comment on your modifications. Maybe one of my other readers would like to post a comment. I've never had any of the problems you've spoken of with an SKS. Like I said, I'm no expert, but I do know that many of the SKSs for sale have fake serial numbers engraved on their parts. I wonder if it's possible that your parts don't really match correctly? SKS's are simple and should be extremely reliable. Have you taken it to a gunsmith for suggestions? I actually would have done that prior to making any modifications. If I had real problems with one of my purchases I would have returned it and asked to swap it out for another rifle. Everyone I know who owns an SKS says that their rifles just keep shooting. At times a gas valve may need replacing, but that should be it. The firing pin replacement is only to stop the possibility of a slamfire. The stock pin should simply work. I wish I could help you more Don. Maybe someone else who reads this can. My Buddy Dirk is very knowledgeable. I'll shoot him an email. maybe he's run into some of these issues. Regards
One more thought Don. My parts seemed unfired (piston, gas valve, etc), but I think they replace them when SKS's are refurbished. My rifles were obviously refurbished. If you look at the stock, if the screws are near the surface of the wood, that is a clear indication that the gun has been reworked. They sand down the stock to make it look new, which brings the countersunk screws to the surface. Also, the butt pad usually will look like someone hit the sides with sandpaper for the same reason.
Don,Have you tried shooting a couple boxes through it with the gas valve closed to see if the bolt face is getting beat up? Drilling the gas block could be the problem.
Don I to have two SKS rifles one Yugo refurb and a NIB Chinese I bought several years ago. The only issue I've ever experienced was with the Yugo and some cycling problem shooting the Wolf ammo several years ago when I first got the rifle. I installed a new gas valve and that issue went away,I learned later that the issue was with the Wolf ammo because the old gas valve worked perfectly with any other ammo I used,that particular lot of Wolf ammo was loaded weak and the old valve had just enough wear on it to not cycle the rifle.
You also have to remember that the Yugoslavian's didn't use steel case ammo in there SKS rifles,the military ammo was brass case,loaded to a slightly higher pressure and the primer cups although harder than your standard soft commercial primer are not as hard as the Russian primers so the wear and tear on the firing pin is much less of an issue as well as the pierced primers you see on some occasions when shooting Russian ammo in Yugo SKS rifles. To further understand the popped primer problem look on the Murry's web site under SKS owners for the info on how he mods the bolt face on the Yugo SKS rifle to help eliminate that along with the use of the spring loaded firing pin.
As far as enlarging the gas port on the Yugo it probably wasn't necessary but it shouldn't hurt anything,you can't really compare the gas port size of the SKS to the AK-47 because the gas piston and bolt carrier are one piece and of much heavier design than that of the SKS so more port pressure is needed to cycle the heavier action.
Also the firing and retainer pin design on the AK is different than the SKS as far as how the firing pin moves inside the bolt and how the retainer pin holds it in place. If the metal on the FP was being gouged it most likely that the pin itself was bent during firing or not installed properly,it's very easy to install the pin upside down.
The firing pin should always rattle freely when the bolt is shaken and it should never be lubed and moved freely from front to back by simply tilting the bolt as such. The first Russian SKS rifle has spring loaded firing pins but it was later dropped mostly to save a step in production. Ans since all other SKS rifle we basically built on the Russian design and technique all other mfg. followed suit.
As far as using any SKS bolt form another country or another SKS rifle it possible if it fits properly. Not all SKS bolts are the same length,also the SKS bolt head spaces on the rear of the bolt when it drops down into battery. If the bolt is to long it want lock into battery if its to short you get excessive head space,the bolt also has to drop down into battery and lock up so that it trips the disconnect in the trigger mechanism so the rifle will fire.
Lastly I wouldn't waste my money on a buffer for the SKS it serves no useful purpose your money is better spent on a TechSight front sight post.
Don,my first SKS was a Yugo I also own a NIB Chinese. You probably didn't need to drill out the gas port on the Yugo to make it cycle unless it just happen to be out of spec.
I had a similar issue with my 1970 refurbed Yugo it wouldn't cycle wolf ammo at all but would function without a hitch with any other brands of ammo including reloads,a new gas valve solved the problem with the Wolf ammo. It was just a combination of slightly worn gas valve and underpowered/lower pressure Wolf ammo. One thing you need to know is that the Yugoslavians didn't use steel case ammo in there SKS rifle,although it should work fine it may cause some issues if ther not addressed and the Yugo military ammo came in three version and most of it was loaded at a slightly higher pressure than your standard steel case Russian fodder so a leaky gas valve in a Yugo wasn't a problem,it was also corrosive so that accounts for some of the wear and tear on so many of the Yugo SKS rifle as far as the gas system goes if the rifles weren't cleaned properly pitted bores and corroded gas system are often a problem if a person doesn't pay attention to what there buying off the rack.
Part 2:
As far as the gas port of the AK being larger than the SKS that is normal,the AK has a lot heavier gas piston and bolt and carrier assembly than the SKS and requires more port pressure to operate/cycle.
Most likely if your shaving metal off the original firing pin either one of several things has happened,it's either bent,worn out or was installed improperly it's pretty easy to turn it upside down during reassembly. I dough it the latter,it most likely cause buy the Russian ammo's hard primer or possibly a pierced primer.
Take a look at he popped primer section on Murray's site and see how he reworks the bolt face on the Yugo SKS rifles. The Russian primers are very hard compared to other countries primers such as the Yugo and South African brass case surplus ammo.
As far as swapping out bolts on the SKS with another be very careful with that although the all look the same there not some a slight longer or shorter than others. The SKS bolt sets it head space on the rear of the bolt,the bolt locks in places when it move forward in the receiver and drops down into battery,if the bolt is to long it want lock u,if it's to short you have excess head space,also if the bolt doesn't lock into batter the disconnect in the trigger mechanism want engage and the rifle want fire.
Also all sks rifle with free floating firing pin will dimple the primer to some extent it's just the nature of the design that's why all the ammo is loaded with mil spec or primer made from hard metals,the exception to that is commercial American made X39 ammo which has a soft primer and should be avoided unless your have the Murray's spring loaded firing pin or reload your own ammo and use CCI or Wolf Mil-Spec primers.
One a side note the first Russian SKS rifles has spring loaded firing pins and were later discontinued why is not really known but since pretty much all the SKS rifle regardless of country were first built using Russian technology and technical advice it stand to reason that no other would have the spring loaded pin either.
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