SKS has problem firing

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blinddog
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SKS has problem firing

Post by blinddog »

I have a 1958 mod. 56 SKS that does not fire all the time. Sometimes it will fire one then skip one or fire two and skip three or four etc. I removed the bolt and the firing pin, the firing pin was way to easy to remove, I did it with my fingers no tools required. I was wondering if I need a new firing pin, one with a spring, or do I need a gunsmith. I have the bolt squeaky clean so I know it's not varnish inside of it. If anyone is familiar with this problem I sure need your help.
max30109
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Re: SKS has problem firing

Post by max30109 »

I'm not an expert by any stretch, but on the Mosin I've been working on there's a firing pin adjustment. There is a gauge as part of the kit that helps you set it. I've been told that the best way to adjust it without the gauge is to tinker until the firing pin sticks out just a bit which you can tell because it will fire in an auto burst and then backing it off just a bit.

So I'd guess the firing pin is not properly adjusted (maybe because of wear). I'd assume there's some kind of adjustment for the firing pin strike and you may be able to fix it that way. If it's not adjustable, then you'd probably need a new firing pin.

But that's just a guess based on the work I've done on my Mosin in the last few weeks.

Max
blinddog
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Re: SKS has problem firing

Post by blinddog »

You kind of verified what I was thinking. The firing pin on my sks is free floating, it has no adjustment as far as I know and there is no spring, however, Murray has a spring loaded firing pin for $39 which I may try after reading your post. Thanks for your input max30109.
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Re: SKS has problem firing

Post by juniustaylor »

I've never messed with a SKS rifle. Looking at the bolt disassembly/reassembly, there are no measurements of the firing pin protrusion, etc.

When your rifle skips a shot or two, are any dimples left on the primers? If the pin is free-floating in the bolt easily, then it sounds like that is okay. You may need to check and verify your firing mechanism is operating properly. Start at your trigger and work your way to the hammer and see if anything isn't right. Check and make sure the hammer is striking the firing pin with good force. I'd probably hold off on spending $39 on a different firing pin with a spring and check your trigger assembly. Is this your first SKS and how long have you had this particular one?

To max30109, to check firing pin protrusion on the Mosin bolt you can use a set of calipers and measure it that way. MIN is .075" and the MAX is .095". I misplaced my tool, so now I have to use calipers. I rarely take it apart though. You can normally eyeball it and get it right on, but I never trust a "calibrated eye", I measure it.

EDIT: That Murray firing pin won't do a darn thing for you. This is its description.
This “New For 2007” replacement firing pin is designed after the original Russian design. And, it will fit all SKS’s. Even pre-51 versions. But, with pre-51 versions you’ll need a different spring. This is due to the hole in the bolt being drilled deeper in “later” versions. This new firing pin will eliminate slam-fire and uncontrollable full-auto incidents! And, it will allow the use of “soft primered “American” ammo, or reloads.
The key points are in the last 2 sentences (underlined). This will not give you a harder strike, it will give you a reduced strike if anything. It would be a waste of $39. It is simply a firing pin with a rebound spring.
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Re: SKS has problem firing

Post by max30109 »

Dang, why would anyone want to eliminate slam fires? That'd take the fun out of owning an SKS... :-)
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Re: SKS has problem firing

Post by Foo Bird »

I had an SKS years ago. The firing pin has no provisions for adjustment. All I knew was to NOT install it backwards unless a magazine emptying full auto slamfire was your idea of fun.

What ammo are you shooting? That may be the problem. I was shooting surplus in my CZ-52 and had approx. 4 failure to fires. Cocked the hammer pulled the trigger again, bang.
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Re: SKS has problem firing

Post by blinddog »

I get a slight demple in the ones that don't fire, I can reload them and fire again with mixed results. I am shooting 2 different typs of ammo, Wolf and Remington, happens with both. I haven't owned the rifle long as a matter of fact this happened the first time I shot it and the guy I got it from said it was shooting great when he had it. Uh Huh! Ok, no Murray pin. I've taken all apart except for the trigger assembly and I will do that tomorrow. Sks is a simple rifle except there are no set specs that I can find. I am not showing any brass in or on the bolt. Thanks for the ideas guys.
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Re: SKS has problem firing

Post by juniustaylor »

Of course it shot good when he had it ;). I wonder if the spring that drives the hammer is a bit weak. Supposedly Wolf ammo has hard primers. Remington should be okay though. Definitely check out the trigger assembly. Sounds like the firing pin is doing what it's supposed to, just isn't getting the necessary force to whack the primers with sufficient force.
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Re: SKS has problem firing

Post by blinddog »

I already have the trigger assembly taken out. I'm going to look for a new hammer spring since that seems to be the culprit. I am going to look around and see if someone has posted something that would be of use to me in finding a new spring. I'm going to go with juniustaylor and say trigger spring. Thanks for all the help guys.
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Re: SKS has problem firing

Post by normsutton »

blinddog

check your firing pin tip and see if its burned or ruff , I have 2 Murray he pins are tops in my book, and all my SKS"s have springs on them after I bought one of Murray's I turn the rest down and put a spring on them,

any way shooting wolf ammo , you could of pierced a primer and the cheap powder swiping's that wolf uses probably fried the firing pin

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juniustaylor
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Re: SKS has problem firing

Post by juniustaylor »

Well, some further reading on Wolf ammo makes it out to have soft(er) primers. Only a handfull of folks ever complained about having pierced primers... maybe I'm not reading in the right spot. I found one forum where Norm said they sucked back in 2007 (Wolf Military Classic). A lot of folks like the actual Wolf primers that you buy to reload with. As Norm said, check your firing pin tip over real well. If it all looks well (no carbon / pitting / etching) then proceed with your trigger assembly and that hammer spring. It just seems so odd how a 33-36# spring could wear out and not hit the firing pin with the necessary force. ?? Almost doesn't seem logical. Head scratcher for sure. With the bolt assembly all together, can you shake it and hear the firing pin rattle back and forth (ensuring it is not binding internally)?

Reading another forum, someone had a similar problem - light strikes. A person suggested that the previous owner of that firearm may have cut a coil or two off the hammer spring to achieve a lighter trigger pull. As a result, performance my suffer and the firing pin won't hit with sufficient force.

Give your hammer spring a look and see if it appears to have been modified. One of the ends won't look factory. Numrich sells the hammer springs for $5.50 each (stock hammer spring) - http://www.gunpartscorp.com/catalog/Det ... atid=11966 There are several other online vendors that sell these parts (buymilsurp.com for example). Browse them all and find the best deal for your dollar!

The sucky part of buying any small parts off the internet is that shipping rates are horrible. If any gunshows were coming up in your area, you could easily find one in there, however, if your gunshows are anything like the ones in KS, you have to pay an admission fee which is often more than the cost of shipping... :(

I really have NO experience with the SKS - never even shot one. I am simply trying to offer ideas to help you figure out your problem.
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Re: SKS has problem firing

Post by blinddog »

Thanks for all of the help. I think it has something to do with the spring. Norm, the firing pin is in excellent condition. It is nice and smooth with no sharpp edges anywhere. And, I will look at the spring to see if it has been modified. Thanks again for all of the goood ideas.
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Re: SKS has problem firing

Post by normsutton »

blinddog

is this the one you have had for years,or is this a new one, i know at one time wolf was making hammer springs for the SKS to lighten the trigger pull , and they didn't work with a lot of ammo this was a few years back, I think they may have corrected that now, if is the one you had for years it may just be worn out

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Re: SKS has problem firing

Post by juniustaylor »

Norm, I asked that question earlier. He said...

I haven't owned the rifle long as a matter of fact this happened the first time I shot it and the guy I got it from said it was shooting great when he had it.

It's hard to say what the previous owner did... old Wolff spring, hacked the original spring. I figure a safe bet would be to get a replacement original spring and see if the function improves.
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Re: SKS has problem firing

Post by blinddog »

I got the SKS back from the gunsmith today. He took it over the weekend and did some test firing to find out the problem. If any one ever has this problem here is the answer. The recoil spring has to fit at the rear of the reciever not on the little ledge that is at the end also. It has to fit loose or it slows the bold down just enough for the bolt not to properly lock up therefore causing the firing pin not to hit the primer hard enough for it to discharge. :oops: :oops:
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