Cast Receiver Breakdown

[padams8888]

New acquisition.  Classic casting line down the center of the receiver. The trigger assembly frame is cast and shows the signs of rough cast where it wasn't machined. The bottom side of the carrier has an interesting numeric stamp. The rear sight block has a smooth milled finish unlike a previous cast rifle I've had.  Rough milling marks on the interior of the receiver. I'll get it entered into the SKS survey. The gas block almost looks like it has a plugged hole on the r/h side.

[Justin Hell]

Neat!

Interesting that it is also a DB and that 721 thing is kind of an eye opener too.  Its also funny that my DB probably has the cast RSB yours should have.

I wonder if the 721 could have anything to do with what seems to be a prefix to the serials (but all in the same size font) on the M21s...and possibly my DB.

It has the ShenYang City stamp as seen with other DBs as well.  I wonder if any of the other cast receivers were also DBs? I don't seem to recall seeing one.

Very cool!!! 

[Loose}{Cannon]

Nice...   a January 1972 gun.   

[carls sks]

nice pics, thanks for sharing. 

[Phosphorus32]

Very cool  Thanks for sharing the detailed pics Pat 

[PowerPlant]

LC - Other than the 'DB 721', how were you able to determine the manufacture date of January 1972.

[Fakahatchee]

New member here, I know this an old thread but I just picked up a DB cast receiver SKS produced 911 units after this one. I'm not a  collector  , just wanted a shooter and found this locally unfired, full of cosmoline and in the box. Didn't know it was a cast receiver untill I started doing some research and found this thread and others describing cast SKS's. Had a Norinco SKS back in the 90's but let it go.

I've put 400 rounds through it , and other than having a sticking firing pin due to some burrs on it that I stoned out it has been reliable. The gun is very accurate.Now the question is how durable are cast receivers, I can't find any negative info on anybody having any problems with them. My thoughts are 7.62X39 being such low pressure it should be fine . This gun is a fine example of well done casting, I would of never known without this thread.Well I'm going to keep shooting it and we'll see what happens. I'll let you know if it blows up.

[running-man]

Nice pickup!  I wouldn't worry about the reliability of a cast receiver SKS too much, the locking piece of keystock that the rear of the bolt locks against while in battery is made of a separate piece of hardened steel. The top rails that hold the carrier down are more likely to have issues, but I've only ever seen those fail when headspacing issues or poorly done reloads with excessive powder are used.

Glad you found the info here useful! 

[Phosphorus32]

Nice find! Have you had it out of the stock? (Engage safety before releasing the trigger group from the receiver.) I’m curious if you see the casting mold ridge in the center.

[Fakahatchee]

The machining and casting on this one is much better than on the OP's example. I don't see any hardened steel piece for locking the bolt, just locks on the frame.   

[Phosphorus32]

Very clean looking 

[running-man]

The machining and casting on this one is much better than on the OP's example. I don't see any hardened steel piece for locking the bolt, just locks on the frame.   

Ahhh it's one of those! 

Justin Hell had one like that I believe.  We hmm'd and haw'd at it a good while but never really came to a conclusion of what they might have been thinking when they made such a radical change like that. They are a bit of a scary beast since every other SKS has something hardened in there for the rear angled surface of the bolt to seat upon, maintain safe headspace, and keep the round in battery. 

The machined receivers all do I believe (I assumed all cast receivers were similar, but clearly they are not the same across all cast receivers):





Even the stamped SKS's had a trunnion style insert riveted into place in that spot:







50 years later, we probably have to assume that the Chinese knew what they were doing as uncomfortable as that might be.  You might check for wear on that surface if you use it heavily.  If it looks like it's rounding over or eroding in any way, I'd probably stop shooting it (though that would be the same for any carbine that was showing wear in a similar way).

[Fakahatchee]

600 rounds down the tube with no problems. The locking surface on the receiver is showing no wear, just a shinny spot were the bolt locks in. Same with the bolt. That casting area in the receiver were the bolt locks is pretty substantial. No wear on the rails, bluing is hardly worn. I think they got the heat treat correct. My guess is for as long as they made the cast receivers there wasn't a durability issue just wasn't cost effective.