SKS Mag Adapter

SKS Magazine Adapter Installation

Installation Instructions

Terms for you to be familiar with and How To - Test Fit The Adapter and Magazine to your SKS:

A – Forward Trunion- (L Shaped forward trunion original with all variants of the SKS Rifle). The trunion is part of the rear sight assembly. It is the portion of the assembly located at 6 O’clock on the bottom of the barrel. This is forward of the rifles magazine well. Do not alter this original Trunion; you need it to lock the forward locking pointo on the Adapter to it.

 

B – Rear SKS Original Box Magazine Latch- This is the spring loaded, original box style magazine latch/release immediately rearward of the rifles magazine well. It is part of the trigger assembly.

C – Trigger Forward Tangs- (These are the forward facing two tangs that are original with all variants of the SKS Rifle). These tangs will need to be made shorter. Measure from the back of the cross pin forward. The length should be .2000 to .2500 inches total.  Take care and remove a little at a time and refit.

The ‘trigger tangs’ on a stock SKS Trigger Assembly (left) measure approximately .4275” from the back side of the latching pin to the front edge of the tangs. These need to be shortened to .2000 - .2500 depending on your rifle.

Then set the Trigger Group aside.

D – This should really be item “T” for Tolerances: The SKS 7.62x39 has some very close tolerances to feed the x39  rounds. You need a big dose of PATIENCE. Do not get frustrated if it does not work the first time. Small adjustments make a big difference in running like butter or jamming. You will love the way this runs with the AR-15 Style Magazines. Go slow until you really understand the relationship of Magazine to Adapter, Magazine to Rifle, Receiver to Bolt, etc. All these parts have to be dancing to the same music, so think symphony orchestra not heavy metal. Thousands of an inchcan make a big difference.

E - Drop free bolt mod (DFBM)- The DFBM may not be required. However, if you wish to remove the mag with the bolt closed, you will need to do this mod, or, if the bolt is binding on the mag lips. The drop free bolt modification reduces the bolt width which allows the AR-15 style magazines to ride higher into the SKS Receiver magazine well.

F – Test Fit the Magazine with the Adapter before installing into the rifle – Take the AR-15 Style Magazine and adapter Hold the Adapter in one hand with it parallel to the floor (just like it would be when mounted into the SKS Rifle). Slide the Magazine into the adapter to see if it will latch up in the adapter before you attempt to mount the adapter into your SKS Rifle. The Magazine loads into the Adapter just like it would load into an AR-15 Style Rifle. Once you have placed the Magazine into the adapter hold the adapter level like it would be in the rifle and press the magazine release button. The Magazine should drop free. This test will help you see it work before you ‘live fire’ this system. This test also lets you see how the Patent Pending Adapter System works. If this test fails, re-think the test…The Magazine should lock into the Adapter and the Magazine Release Button should release the magazine and Gravity should cause the magazine to drop out of the Adapter System freely. Some ‘wear-in’ of the mag may be needed to ‘loosen’ it up. Also if the mag binds up as the adapter may be sanded to create more room. Especially if it’s a specific portion that is binding.

Modifications to SKS Rifle

The rifle needs to modified for the magazines to fit properly.

Step 1: Modify the trigger assembly. See “Trigger Forward Tangs” above. This can be reversed with a new trigger assembly.

Step 2: Remove the BHO device and shorten it by .2000 approximately from the bottom. This is necessary so the rear of the mag will penetrate high enough for it to lock up. This can be reversed with a new BHO. I havent had to do this but may be necessary on some rifles. Best to see if the rifle feeds first.

Step 3: Using a mill, X/Y axis drill press, Dremel or similar. Best to have a machinist or gunsmith do this. Remove the bullet ramps at the rear of the chamber on either side of the receiver. This is necessary for the mag to insert high enough into the rifle magwell and lock up. This step cannot be reversed.  remove enough material so the reciever edges are level all the way all the where the mag would touch.

Options for Modifications to fit AR magazines

There are 2 options to fit the magazines.  The first it to modify the rifle receiver to accept the AR style mags.  The second option, which is recommended is to modify the magazine to fit the SKS

Option 1:

Modify the rifle to accept non modified AR 15 Mags

This option is for modifying the rifle to accept UNMODIFIED mags of any capacity. However, once done, it cannot be undone. 

Using a mill, X/Y axis drill press, Dremel or similar. Best to have a machinist or gunsmith do this. Cut down the cross bar (feed ramp) at the rear of the chamber. This is necessary for the mag to insert high enough into the rifle magwell and lock up. This step cannot be reversed.  Only enough material should be removed to allow the magazine to sit flush with the reciever rails.  When looking through the ejection port the feed lips of the magazine should be parallel with the receiver edges and tough all the way along.

Option 2: (Modify mags)

This option is for modifying the Magazine to fit the rifle.

Step 1: You need to cut down the front of the magazine case about 1-2 mm I’ve included pictures below that show a modified and unmodified magazine. Take of a little first then go to step 2 

Step 2:  Thats it, Test fit the mag. If it doesnt lock in place take off a bit more.. and try again

Maybe Step 3: When testing (always use snap caps or dummies) remember that you let the bold slam closed. If you finding that rounds are hitting just below the chamber and not chambering we have found this to be caused by the magazine. Make sure the feed lips sit right up against the reciever frames and doest drop down. The height of the magazine can be adjusted by adding or subtracing from the top of the magazine catch. In this case you would add material to the top of the mag catch to hold the magazine higher. I would suggest bondo as it holds well with the plastic, is sandable and can be finished easily. If the magazine lips are against the reciever the next step would be to unbend the little indents on the front of the magazine lips as these can push the bullet down on feeding instead of letting it feed strait.


The SKS Adapter – Test Fit and Installation:

HOW TO FIT THE ADAPTER to your SKS Rifle. THESE STEPS APPLY TO THE FITTING, INSTALLATION and TESTING PROCESS. 

1. Clear the rifle of all ammo. Remove the SKS Box Style magazine, follower, and spring. Ensure all magazines you are working with are free of any ammo.

2. Place rifle on your worktable, magazine well facing up, with the FCG (Fire Control Group) in place. 

3. Reinstall the trigger group into the rifle.

4. The SKS Adapter ships completely assembled. With the rifle lying flat on your work surface with the bottom of the rifle facing up, place the Adapter magazine well over the rifle magazine well and the  “duckbill” of the Adapter pointing forward, The Adapter should slide in and lock like a stock magazine, However, at this point is wont as the magazine catch won’t fit into the stock. Make a mark where the magazine catch meets the stock and start removing material from the stock. You can estimate by eye how much is needed, but remove a little at a time until when you instert the adapter it can lock in place (you may have to puch the original mag latch in as it should be quite tight). If the adapter is all the way down and touching the stock and still wont lock in place you may have to sand down some of the adapter to get the mating working between the mag adapter and stock so that the rear origianl latch will engage. When the adapter is locked in place make sure the mag release on the adapter works smoothly and isnt rubbing on anything.     

5. Try insterting the magazine. If the magazine won’t fully insert into the rifle then take it out and look through the magwell adapter. If you see any part of the stock that is visible through the magwell this part of the stock has to be removed. We usually only found the front corners visible through the magwell... its’ a very small amount but will catch the magazine and preventing from fully entering the magazine 

6 Place rifle on your worktable, with the rifle magazine well facing up at you.

  1. With the adapter on your rifle, make sure the front locking lug of the adapter is in place and holding in the front trunion.

  2. Make sure the rear of the adapter is held in place by the rear mag locking tab. You want to be able to slide the adapter body.

  3. Insert the mag with your other hand (it should easily lock into the Magazine well, if it doesnt’ you may not have done the magazine modification or feedramp modification). If you have done the mods and it still doesn’t catch, ie, it doesn’t go up far enough look though the ejection port with the bold locked back. The magazine lips should be touching or almost touching the reciever rails and be parralel to them. If they are dont reach the reciver then check your magazine modification or your feedramp modification, which ever one you decided to do.

  4. If the magazine lips are against the reciever and the magazine still doesnt catch its probably that the magazine catch is too high and the top of the magazine catch can be sanded down (a little at a time) unitl the magazine catches and it fits well against the reciever rails.

  5. If the magazine catches but is held without touching the reciever, you may need to add some material (We recommend Bondo) to the top of the mag catch. Once dry sand smooth and level and try again. Repeat as necessary to get the correct height.

  6. Lastly, you can optionally fill any gaps inbetween the mag adapter and stock. Again Bondo works well, but apply it to the mag adapter, let it dry and sand as needed till you get the fit you want. This is an optional step. The adapter lcan be loose and as long as the adpater locks into the rifle fully and the magazine locks up properly in the mag adapter everything should work well and the magazine should be kept tight against the rifle.

5. Mag Function Tests of the system: Read ALL of Section 5 before you proceed. Once you have the Adapter position adjusted to your rifle (using the steps from #4 above), you should be able to insert and lock the magazine in your adapter using only one finger. If the magazine locks up and releases freely you are ready to cycle a few rounds as a test. If it doesn’t pass this test (the single finger test), Relook at the height of the magazine catch as some may need to be taken off to allow free use. Also make sure that the mag release on the adapter operates smoothly with the mag in and out and doesn’t bind. 

Using a modified magazine (unless you modifed the feed ramp), for the SKS Adapter, load 4 or 6 rounds into the magazine. Lock the bolt open (safety on) using the SKS bolt hold open (BHO) to keep the bolt locked rearward. Insert the magazine and charge the rifle. Please do this outside if possible and in a safe manner, or even better use dummy rounds or snap caps. The bolt should fly forward and scrap a round and go into battery ready to fire. You should be able to cycle the 4 to 6 rounds one right behind the other when pulling the bolt all the way back and letting it ‘fly’ forward repeatedly. Dont ride the charging handle down as the rifle is meant to slam the new round into the chamber.

5.1 Notes and experience from our tests: 

5.1.1 The Magazines should be cleaned on the inside and outside. If the magazine is not clean rounds may not move as freely as they will when clean. We use a dry silicone spray to lube the inside of the magazines and find this works well for us. 

5.1.2 Steel Case Rounds have less resistance inside the magazine than softer Brass Rounds. If you have steel case rounds we suggest you use steel case rounds during your adjustment to find the ‘sweet spot’ on your particular rifle. If you are having feeding issues please email us and send pics with the problems. We will work with you to resolve the issue including sending you a new modified adapter for your rifle if needed. 

6. Rifle Stock Adjustments to accept the Adapter – (every stock manufacture will have slight differences) The Adapter is wider than the stock opening in any SKS Rifle Stock. The adapter sits ontop of the stock and uses the existing magwel to help guide the magazine to the proper position. You will need to open up the stock to allow the stock to fit around the magainze. Hopefully this isn’t much and is covered in the installation instruction in 4.4.

At this printing, there are no after-market “ready-to-go” stocks for the SKS Adapter that are ‘drop-in ready”. But there is hopefullly little modification to the stock. If you have a stock that accepts the adapter and magazine without modification (not including the magazine catch). Let us know.

7. Final Assembly Of Your Rifle: 

Congrats you are almost finished. You need your SKS rifle, the FCG correctly trimmed, your stock properly trimmed, a modified magazine (Or modified free ramp) and your properly fitted adapter. Install the stock onto your SKS. Lock the FCG in place. Insert the magazine adapter per the above instructions. Check that the Adapter is locked in place correctly. Lock the bolt back using the BHO. Insert the empty mag and re-check for proper operation as you did in step 5.

8. If you still have problems call us via email: info@sksmagadapters.com 

9. Go to the range and have fun and be safe.