Author Topic: SKS Saga - Recoil Springs  (Read 2435 times)

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SKS Saga - Recoil Springs
« on: October 19, 2012, 04:41:31 PM »
As many of you own and maintain semi-automatic firearms, you understand the importance of keeping recoil springs in top-notch shape. After all, recoil springs are one of the key components in the operation of the firearm.

If you have been following my SKS saga, you already know that I recently purchased two of them and that, as with most folks, want to assure myself that my firearms are completely functional and operational - ready to be used at any time.

SKS #1 was showing signs of the bolt battering the frame of the gun, as was SKS #2. SKS #2 was in worse shape than SKS #1 and it garnered my attention first. The recoil springs of both rifles were suspect as I did not know how long the recoil springs had been installed nor how many rounds of ammunition they had cycled. The frst step was to order new recoil springs and I decided than rather in just ordering the springs separately that I would replace the entire recoil spring assembly that includes the recoil spring, small guide, and large guide. This would make replacing the recoil springs a simple drop-in installation. Since I would have two spare recoil spring assemblies, I did order two replacement recoil springs so that I would have two spare drop-in recoil spring assemblies for future use.

Replacing recoil springs on the SKS takes very little time (about 30 seconds for dis-assembly and assembly - after you don eye protection) so I felt that although I could not recapture the time spent changing out recoil springs, the effort was well worth the time spent.

Now, I'm sure that the military services that used the SKS was not concerned about weak recoil springs. The SKS, after all, was intended to be a battle rifle and if one failed there was another one that would take it's place rather quickly - usually a battlefield pick-up from a former user of the weapon. Since there are no SKS floating around the neighborhood, I decided to start purchasing spare parts in case they should be needed at some time. Firing pins, firing pin retaining pins, extractors and extractor springs, gas pistons and gas piston springs, etc. are being accumulated. Due to the nature of recoil springs, several will be on hand.

After replacing the recoil spring assemblies in both rifles, I dis-assembled both of the previous recoil spring assemblies to see how the recoil springs compared with the original (original in the fact that they were both in the rifles when I bought them and I did not know if, in fact, they were recoil springs that were originally installed in the rifles). I was quite surprised at the result of the comparison and thought that I would share it with you.

In the accompanying image, you will see three recoil springs. The very top spring is a new recoil spring that measures 13 1/2" in length. Second from the top is the recoil spring removed from SKS #1 and measures 13 5/16". Note that I had mentioned about the beginnings of the bolt slamming against the frame of the rifle, as "peening" of the frame was a telltale sign. 

The worst of the lot is third from the top; the recoil spring from SKS #2. Note the length of the recoil spring as compared to the new (and the recoil spring from SKS #1). It's shorter length (12 7/8") is significant and explains the dominant signs of the bolt battering the frame. Notice also that the recoil spring from SKS #2 is deformed; a sure sign of spring failure. I suspect that this recoil spring not only contributed to the rear of the bolt slamming against the frame but also may have prevented the bolt from completely locking into place in the "well" and has contributed to the wear marks that I observed on the bottom of the bolt that may have resulted by the bolt carrier not being forced into complete battery that, in turn, forces the bolt into the well.

From this analysis I determined that I should keep the spare recoil springs uninstalled as an assembly until they are needed; they will remain 'not compressed' until installed. I also determined that ordering two more spares might be in order since they are a high-wear item and the MTBF (Mean Time Between Failure) is unknown. Besides, cleaning original issue recoil springs allows me the joy of using mineral spirits to remove all of the cosmoline packed in and around them and that protects them from rusting in storage.

The SKSs now have new recoil spring assemblies and to help protect the rifles a little more I have installed a Black Jack H-buffer in each of them, which prevents the bolt from slamming into metal. By the way, and by design, the bolt of the SKS was intended to contact the rear of the receiver to stop its rearward motion during recycling of the bolt. However, a weak recoil spring makes this contact excessive. Since I plan on keeping and using these rifles for a long time, I believe that the investment in restoring and maintaining them is worthwhile.

My advice is that if you own a SKS that you inspect the recoil spring and replace it if necessary. You can use the dimensions that I provided earlier (13 1/2" for a new spring) as a guide in determining if the recoil spring needs to be replaced.

As a side note, I have also installed the Black Jack "H" buffer in both firearms to try them out. The "H" buffer inserts into the frame where the bolt would normally hit the frame. It does shorten the stroke slightly, but the buffer can be trimmed back if the stroke is too short. I'll be at the range this weekend to try SKS #2 out and see how it fares with the new recoil spring and buffer.

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