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* First is the possibility of a "slamfire," or worse the ignition of a round out of battery.
* The second
being accidental discharge due to poor hammer/sear engagement.
Slamfires
A "slamfire" is essentially an unintentional
and uncontrollable discharge of more than one round. It may be 2 of 3 rounds being fired instantaneously, or the complete
emptying of the magazine. It is usually caused by a seized firing pin--due to debris, powder residue, cosmoline, or a host
of other substances. It can also be caused by using commercial ammunition with soft primers. This is dangerous because it
can happen unexpectedly and without warning. Yourself or others could be harmed, or worse.
The SKS Carbine features
a "free-Floating" firing pin which means it has no spring to return and hold the pin rear-ward in the bolt. Since the firing
pin can freely "rattle" inside the bolt body, extra care must be taken to ensure the firing pin channel remains clean. If
the firing pin becomes stuck in a protruded manner, and bolt is closed, the pin will strike the primer and ignite the round.
It is also possible that the first round will not be ignited until the trigger is pulled, which will then jam the firing pin
forward to the protruded postition, triggering the involuntary ingition of some or all remaining rounds.
Since the
SKS Carbine is a semi-automatic firearm, it will reload instantly after the first round is fired. If the firing pin remains
stuck in the forward position, primers will continue to be struck involuntarily (without using the trigger) until all remaining
live rounds are fired. It is easy to see why this is an unsafe condition.
The easiest way to remedy this problem is to
assure your bolt is clean of any and all residue. This can be done by many methods. Complete dis-assembly, inspection, and
cleaning is my preferred method.
It is my recommendation that the bolt be completely disassembled and the firing pin
channel be cleaned thoroughly (I find myself using pipe cleaners and non-chlorinated brake cleaner). Soaking the bolt assembly
is not sufficient enough to clean out hardened, sticky cosmoline and other foreign debris. I also discourage oiling the pin,
as oils will only attract dirt and other residues eventually seizing the pin (and that is what you're trying to avoid!!!).
For a detailed technical artical on how to dis-assemble your bolt, visit Surplusrifle.com's article on Bolt Disassembly/Reassembly
A few side notes:
* Though firing pin orientation doesn't typically matter, in some Chinese variants the firing
pin can be replaced upside-down in the bolt body, jamming it in the protruded postition. It might not be a bad idea to mark
your firing pin's orientation with the body before your remove in from the bolt.
* Ben Murray makes a retro-fit kit that
replaces your firing pin, with a new pin and spring. This will virtually elimitate the possibilitly of a "slamfire" all-together.
For more info check out Ben Murray's website.
Hammer/Sear Engagement
This section will discuss the trigger group,
with emphasis on the hammer and sear.
There are 3 types of Hammer/Sear Engagement. They are:
* Negative Engagement
- As the trigger is slowly pulled, the hammer moves forward slowly before breaking and contacting the firing pin.
* Neutral
Engagement - As the trigger is slowly pulled, the hammer remains neutral and does not move before breaking and contacting
the firing pin.
* Positive Engagement - As the trigger is slowly pulled, the hammer moves rearward slowly before breaking
and contacting the firing pin.
Of the three types of hammer/sear engagement, the positive type is the safest and
most desirable.
To check your SKS, pull your bolt back to cock the hammer, then remove your receiver cover and recoil
spring. Take care not to let the recoil spring shoot across the room! You can now look down to see your hammer. Slowly squeeze
the trigger while watching the movement of the hammer. You may have to repeat several times, as the movement can and will
be minimal. (Keep your fingers clear).
Why is hammer/sear engagement so important?
The safety mechanism on
the SKS simply acts as "doorstop" to the trigger. It does not disconnect the sear, or cease function of the hammer. Instead,
it simply keeps the trigger from moving rearward. If the rifle is cocked and loaded, and is knocked, dropped, bumped, or the
likewise the sear can still move and the hammer can still drop. This is especially the case with a negative hammer/sear engagement.
The best way to describe how this could happen is to use an analogy.
Let's say your car is dangling on the edge
of a cliff, ready to fall hundreds of feet to the bottom of a canyon. (This is the hammer in the cocked position.)
*
If a bird lands on the hood of your car, which is over the edge of the cliff, your car will teeter and fall into the canyon.
(This is negative engagement as your SKS is accidentally bumped)
* If you remain motionless in your car, as it teeters
on the edge, you will most likely just remain there staring out the windshield at your possible demise. (This is neutral engagement)
* If a tow-truck happens by and hooks up to the rear bumper of your car, pulling you away from the edge of the cliff,
you will be saved from catastrophe. (This is positive sear engagement)
But that doesn't make sense! How does it work?
When the hammer is in the cocked (rearward) position, it's edge is resting on the sear. If you have a negative hammer/sear
engagement, the sear actually slopes downward toward the edge where the hammer releases. If the SKS is jarred or bumped, the
hammer can, under the tension of the hammer spring, slip down that slope to the end of the sear and release firing the chambered
round!
How do you correct this?
Positive hammer/sear engagement! If the sear slopes in the opposite direction
as it does in a negative engagement situation, if the SKS is bumped or jarred the hammer is forced away from the face of the
sear and the hammer cannot possibly be released!
My recommendation is: If you have a negative or even a neutral hammer/sear
engagement, GET IT FIXED!!!
I will cover a do-it-yourself method further down in this article.
In the mean time take
extreme caution while handling. Take special care not to bump or jar the firearm, as this could accidentally set the hammer
free.
Addressing the SKS Trigger
The SKS Carbine trigger, in general, is made to have a lot of trigger creep.
If your SKS is like most, there is some slack in the trigger. Once you get past the slack, the second stage of the trigger
is fairly rough and heavy. In most cases the "creep" experienced in the second stage is quite lengthy.
What is the
reason for this long pull 2-stage trigger? It is most likely a safety concern. It is not uncommon to have new military recruits
that have little or no firearms experience. It is safer to give them a weapon with a long trigger pull with a lot of slack
over one with a "hair-trigger." There is a lesser chance of accidental discharge by a jumpy cadet in a stressful situation.
This becomes especially critical when the user is running/jumping/diving around in the mud, concentrating on everything else
but his weapon. The extra creep helps to assure the SKS only fires when the user means for it to fire.
The creep also
acts as a cushion for poor hammer/sear engagement. In most cases this large cushion of creep will help keep the hammer from
releasing if bumped or jarred no matter how poor your hammer/sear engagement is. I still recommend you remedy neutral and/or
negative engagement as it is still possible for the hammer to accidentally release.
My first SKS had negative hammer/sear
engagement. As a test, I cocked the hammer and bumped the unloaded firearm firmly on the ground 3-4 times. "CLICK!" the hammer
struck. The test was repeated with the same results. Imagine if the firearm were loaded. A bump against a tree, accidentally
dropping it, tripping on a root...all of these situations could be potentially lethal with the unsafe firearm.
The
SKS trigger is fairly complex in design, so If you don't feel comfortable taking it apart or making any modifications then
please don't! If you would like to reduce the creep in your trigger, smooth out much of the roughness, lighten your pull,
and remedy your hammer/ sear engagement problems, visit Kivaari's Little Armory for an SKS Target/Match Safety Trigger Job.
He comes highly recommended, has a quick turn around, and will leave you in awe. You will shoot better, and more happily!
If you would like to learn a little more about how the trigger works, and possibly make your trigger function a little
better on your own, please read on!
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