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Inspection Protocol for SKS Carbines

General

1. This concerns the inspection of certain Russian made SKS carbines to determine if they are susceptible to firing in the full automatic mode.

2. The protocol is designed to be quick and simple and not involve the discharge of live ammunition. While revealing obvious potential for full automatic fire, there may be some conditions not detectable through this protocol. Suspect firearms should be isolated for more detailed testing.

3. The full automatic fire issue addressed by this protocol is caused by deficiencies in the trigger mechanism and is not related to previously reported instances caused by hardened grease or other foreign materials embedded in the bolt and interfering with the free movement of the firing pin.

4. One sample was inspected in October, 2014 which would fire only in the full automatic mode, was prone to shock discharge, and had an incomplete safety switch mechanism. Discharge of the carbine could be initiated simply by following the normal loading and cocking sequence. The full automatic fire capability could be migrated from one SKS carbine to another by moving the trigger mechanism thus establishing the problem lies solely in the trigger mechanism.

Scope

5. This protocol applies to Russian made SKS carbines manufactured in either the Tula or Izhevsk arsenal. These carbines are identified via the manufacturer's logo found on the upper rear surface of the receiver cover. Typical markings for the two main arsenals where the SKS carbine was manufactured are illustrated in figure 1 and figure 2. Note that the exact nature of the arsenal marks varies slightly from year to year.

Figure 1: Izhevsk arsenal marking

Figure 1: Izhevsk arsenal marking

Figure 2: Tula arsenal marking

Figure 2: Tula arsenal marking

6. This protocol applies to SKS carbines having the later (post 1951) simplified version of the trigger mechanism installed. The differences are depicted in figure 3.

7. The later version of the SKS trigger mechanism has an enlarged inspection hole (a); does not have the pin holes for mounting the semiautomatic disconnector (b); and the semiautomatic disconnector (c) is absent.

Figure 3: early (below) and later (above) SKS trigger mechanism

Figure 3: early (below) and later (above) SKS trigger mechanism

The Inspection Protocol

8. The inspection protocol is detailed in the table below. The same protocol is attached as Appendix A in a checklist format.

STEP PROCEDURE
1 Prove the SKS carbine unloaded.
2 Degrease the SKS carbine as required.
3 Apply the safety switch and verify that the carbine cannot be discharged by pulling the trigger.
4 Verify the Russian origin of the SKS carbine.
5 Dissassemble the trigger mechanism and verify the presence of the later version of the trigger mechanism.
6 Reassemble the trigger mechanism.
7 Release the magazine to permit free movement of the bolt and bolt carrier.
8 Cock the mechanism gently restoring the bolt carrier to the forward and locked position.
9 Pointing the carbine in a safe direction, fire the mechanism, and keep the trigger pulled fully to the rear. A distinct "click" should be audible as the hammer falls forward.
10 Re-cock the action manually releasing the bolt carrier at the rearmost point permitting the bolt and bolt carrier to move without interference to the forward and locked position under the power of the return spring.
11 Fully release the trigger and immediately pull the trigger to the rear again. If the "click" of the hammer fall is heard, the firearm is operating in the semiautomatic mode. If no "click" is audible and there is no appreciable resistance to the rearward movement of the trigger, the carbine is most likely operating in the full automatic mode.
12 Carbines which appear to be operating in the full automatic mode are to be quarantined pending further testing.

Follow-up

9. The results of SKS carbine inspections are to be reported to the CFO office in the province or territory where the test was conducted.

10. Questions about the test protocol and related procedures are to be directed to the CFO's office.

Murray A. Smith
Manager, Specialized Firearms Support Services
RCMP Canadian Firearms Program

Appendix A

SKS Carbine Test Protocol

Serial number  
Date of inspection  
Business name  
Name and signature of inspector  
Comments  
STEP PROCEDURE RESULTS and COMMENTS
1 Prove the SKS carbine unloaded.  
2 Degrease the SKS carbine as required.  
3 Apply the safety switch and verify that the carbine cannot be discharged by pulling the trigger.  
4 Verify the Russian origin of the SKS carbine.  
5 Dissassemble the trigger mechanism and verify the presence of the later version of the trigger mechanism.  
6 Reassemble the trigger mechanism.  
7 Release the magazine to permit free movement of the bolt and bolt carrier.  
8 Cock the mechanism gently restoring the bolt carrier to the forward and locked position.  
9 Pointing the carbine in a safe direction, fire the mechanism, and keep the trigger pulled fully to the rear. A distinct "click" should be audible as the hammer falls forward.  
10 Re-cock the action manually releasing the bolt carrier at the rearmost point permitting the bolt and bolt carrier to move without interference to the forward and locked position under the power of the return spring.  
11 Fully release the trigger and immediately pull the trigger to the rear again. If the "click" of the hammer fall is heard, the firearm is operating in the semiautomatic mode. If no "click" is audible and there is no appreciable resistance to the rearward movement of the trigger, the carbine is most likely operating in the full automatic mode.  
12 Carbines which appear to be operating in the full automatic mode are to be quarantined pending further testing.