49/50 Tula SKS

[jstin2]

I just added a couple pictures of my trigger S/N for your inspection. It is quite odd that there are similar features between krislhull's carbine and mine. Dated receiver cover - 49, solid latch pin and early style cover, 45 degree port, blade bayonet and the first letter on S/N which is usually found on 50s. Also my trigger doesn't look scrubbed, but bolt carrier was.

[jstin2]

I was just looking at survivor forum and  there was a question about 2 recent 49s on gunbroker. One looks like 49 cover with 2 line S/N and refurb mark, 45 degree gas port, solid latch pin and blade bayonet. The other was similar but couldn't see S/N on cover and it looks like cover was partially scrubbed. Possible 2 more examples of krislhull and mine??  Now 49 or 50??

[running-man]

jstin2, I don't understand this fixation with '49 covers automatically making the gun a '49.  All these guns have no other '49 features except for the early bolt which wasn't changed until '51.  S/N analysis shows a strong trend of yours and the OP's Ш prefix both being '50s. 

The CM2345 on gunbroker has a long tab receiver cover lever.  It also has this cousin in the survey:
Actual Year   Prefix 1   Prefix 2   #   Suffix   Rec. Tula Star   Refurb.   Receiver Cover Year   Stock Year   Stock Type   Refurb Stamp   Refurb Stamp Location   Gas Block   Receiver Cover Latch   Bayo Lug   Receiver Type   Gas Tube Latch   Bayonet   Importer
1950   С   М   875         Heavy   1950   Refurb   Hardwood Amber   1st GRAU / Balakleya   Receiver Cover   45°   Long Stamped   Square Ear Solid   Early Tall   Tabbed   Blade Matte   CAI Unk

The ИK252's receiver cover is ground so much as to almost be unreadable.  It also has a cousin in the survey:




Note the receiver takedown lever is a late hoop.  The late hoops have not been observed on a '49 (yet) but have indeed been observed on a '50.  These late hoops are incredibly rare, likely because the thinness of the metal at the bend caused them to break easily when the hoop was tugged with a tool.  The long lug takedown levers quickly came about in early '50 and by mid '50 the standard short lug takedown lever was here to stay.

[Loose}{Cannon]

jstin2, I don't understand this fixation with '49 covers automatically making the gun a '49

Or and refurb guns cover for that matter. 

[jstin2]

R-M -  I see what you mean about the latch lever. When did they stop using a solid lever arm with eyelet and go to having it riveted? From what I could see 49 and early 50s had the solid arm attachment. From my limited collection, the solid arm with eyelet was being used when date was engraved. I have one that is date stamped and the arm is riveted but still has a eyelet hole. Also if the latch pin was damaged, what would refurb replace it with a stronger latch, as the eyelet holes are a week point? From what I can see, there were 3 different latch pins that could be used on 49/50 receiver cover. Eyelet with solid arm(no rivet) 1.52 mm, eyelet with solid arm(rivet) 1.17 mm and then the no eyelet with rivet.

[Justin Hell]

Interesting, I didn't know about there being two types of eyelet latches.

Is the progression like this?
49 solid eyelet
early 50 stamped/riveted eyelet
earlyish 50 long stamped/riveted
late 50 short stamped/riveted

At least that nudges my 49/50 closer to being a 49.

I measured my solid eyelet shaft thickness vs. a Chinese I had loose and laying around...both actually have the same diameter, 5.5mm.  The difference is the diameter of the retaining pin.  I would measure those pins, but with only 11 rounds down the pipe since restoring it, mine is GONE...and the Chinese one never had it either. If one were to file down that pin to the correct diameter for the OP's cover, that would be all that is required to make that work.  At this point, sans pin, I could put my loop on my Sporter....and this pinless Chinese would slip right on into my 49.  For some reason, likely an optical illusion...the diameter seemed smaller to me....but they are the same.  Running a file through the pin gap on the cover could also be done.  ( I haven't checked out the photos you guys posted yet)

Perhaps during the lever hoopla going on in 50 they actually made some of the stamped levers with the smaller pin?

(If anyone sees a long nubbed FSB or a solid eyelet (with a pin) for sale anywhere, LMK)

Edit: I just saw jstin2's refurbed 49, and it indeed looks like it is a stamped lever with the small retaining pin. I didn't find krislhulls photos though....I am curious about his magazine though, does it NOT have the rivet for the spring post or is it just cut off in the photo?  That would be neat to see an early 49 mag on a late 50 too!

[running-man]

R-M -  I see what you mean about the latch lever. When did they stop using a solid lever arm with eyelet and go to having it riveted? From what I could see 49 and early 50s had the solid arm attachment. From my limited collection, the solid arm with eyelet was being used when date was engraved. I have one that is date stamped and the arm is riveted but still has a eyelet hole. Also if the latch pin was damaged, what would refurb replace it with a stronger latch, as the eyelet holes are a week point? From what I can see, there were 3 different latch pins that could be used on 49/50 receiver cover. Eyelet with solid arm(no rivet) 1.52 mm, eyelet with solid arm(rivet) 1.17 mm and then the no eyelet with rivet.

Early to mid '50 is my best guess on when the changeover was made from early hoop (solid arm) to late hoop (riveted arm).  If I'm reading the red text correctly and you have a late hoop on a gun, I'd very much like to see the gun and particularly detailed photos of the late hoop.  As I said, these are incredibly rare and would very much like to get as much data on your specimen as possible. 

I've never tracked the diameter of the cross pin, it makes sense that they would be different if there was a design change.  It looks like there's a 0.013" difference in the diameter from the two pins you measured.  That pin fits through the slot in the receiver cover, but it rests in a slot milled out in the receiver in the closed position (keeping the takedown lever pulled tight into the receiver while closed).  I wonder if that slot changed width or position with the cross pin change?  You would think it would have had to but it's not something I've ever measured.

Interesting, I didn't know about there being two types of eyelet latches.

Is the progression like this?
49 solid eyelet
early 50 stamped/riveted eyelet
earlyish 50 long stamped/riveted
late 50 short stamped/riveted

Justin, my understanding is:
'49 - Early Hoop
'50 - Early Hoop -> Late Hoop -> Long Tab Stamped -> Short Tab Stamped
'51 onward - Short Tab Stamped

These did get replaced, you see short tab stamped takedown levers on refurbished '49's with all other early features and matching prefix specimens with early hoop levers.  I suspect they could get snagged on things and broken off or perhaps wear/spring out of shape resulting in a floppy lever that doesn't stay closed in the detent during firing.  I know one of my Chinese Sinobanians has a takedown lever you have to pay special attention to as it has a tendency to work itself loose during the course of going through a full magazine. 

[jstin2]

The measurements that I gave were for the thickness of loop. Heading out, but will take pictures this afternoon.

[running-man]

Ahh, I was thinking it was the cross pins. 

Kool beans! 

[jstin2]

R-M - I took some pictures and to help you out, I used a micrometer to take measurements. Early and middle are on my 50s and the later is on my 49 refurbed.
                Pin       Tab thickness      Inside eyelet     Outside tab    Total arm length
Early   -  2.01             1.62                   5.08                 8.93               25.30
Middle -  1.98             1.34                   5.12                 7.84               25.64
Late    -  2.05             1.33                    ----                  7.77              33.05

It was hard to measure the diameter of pin and take pictures, so measured and wrote it down.
Tab thickness is different from my first readings. On first set I used the blade of the calipers and second I used flat part.
https://ibb.co/album/imDMiv

[running-man]

Great stuff jstin2.  Pin diameters are well within manufacturing tolerances.  There is no reason this pin would cause any problems for any type of receiver cover - early or late.

The arm length is interesting.  They must have wanted a bit more leverage or needed additional length for the bend in the short tabbed design.  The fact that it fits into the '49's receiver detent tells me the detent locations are identical and the extra length is all in the tab.

[running-man]

I got some photos from jstin2 showing his late hoop takedown lever in excellent detail. I knew these were neat, but now that I get to see the nuances for the first time, they are simply awesome! (click on any photo to enlarge)

So here's a typical early hoop takedown lever:





Now here's justin2's late takedown lever:




They went from a forged lever that was either integral with the pin or at the very least welded and heavily ground to a lever stamped from sheet metal, bent in two different directions, and finally swaged onto the pin.  This is a simpler method of fabrication.

When they decided to move on from the late hoop to the long tab and finally the short tab, they simplified even further, eliminating the pawl and replacing it with a dimple to fit the detent on the receiver.  The whole stamping and bending operation could then be performed with a single die in one step and then easily swaged onto a pin.




The extra length in in the long/short tab levers comes from the fact the dimple aligns to the same detent on the receiver, but this used to be the tip of the lever on the early and late hoop versions.  Neat stuff! 

[Phosphorus32]

Cool series of photos.  Yeah that stamped lever with a big hole in it doesn't look like a weak point at all   

[running-man]

I've only seen the late hoops on И prefixed '50's.  It will be interesting to see if any others turn up.  I suspect the Russians realized they had made a design error pretty quickly based on the sudden appearance of the long tab levers. 

[Justin Hell]

So the real question is what is Jstin2 going to do now that his Russian SKS takedown lever collection is complete? 

Neat stuff, those late looped levers look so frail it is a miracle any survived...I also hadn't seen the long tabbed ones before either, those just look awkward.  It's crazy how much change happened with those in such a short time.  I really like the early looped ones best, both in looks and how they feel in use. It's too bad the machining process must have been ridiculous vs. the final design.  It seems odd that the late loops seemed more complicated to make though.

I still would like to know the measurements on those tiny retaining pins though...and whether a replacement on a 49/50 with an early cover simply had a different size or different type of pin used.  I thought about a pin shaped like a Battleship peg for that problem...but that sounds implausible.  I can't help but try think about it until I can replace mine with something...the smallest roll pin I can find locally can't even substitute.

Right before posting I remembered seeing this the other day...it's a new aftermarket lever that is just crazy looking, and it comes with pin that looks like a Battleship peg.

https://www.ebay.com/itm/SKS-Rifle-RECEIVER-COVER-PIN-New-Part-BEST-BUY/282834905186?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2055119.m1438.l2649

[jstin2]

Justin Hell, until Running Man mentioned the latch pins, I didn't realize that there was a difference. It was only when I took carbines out of safe that I noticed and posted. Carbines are back in safe. Also you asked about pin diameter, I have them posted on reply #29.

[carls sks]

  have learned something , I didn't know they were made with a hole.  thanks everyone. 

[Justin Hell]

Justin Hell, until Running Man mentioned the latch pins, I didn't realize that there was a difference. It was only when I took carbines out of safe that I noticed and posted. Carbines are back in safe. Also you asked about pin diameter, I have them posted on reply #29.

I actually meant the length of the pins this time, since it seems that is the deciding factor on whether they will work with the early covers or not.

I was kidding around about your collection, and a little green with envy as I realize I will have as many Russians in the 49/50 era as Chinese by the time I get each variant seemingly possible.  It might be a futile cause considering how infrequent Russians are let go by people around here.  Now that the lever cat is out of the bag...I expect 50's to start becoming as sought after as 49s....maybe more so. This is fun.

[jstin2]

Justin Hell - It is not only the length of pin but also the diameter of pin that makes it possible.
1950 pin length 6.95mm  diameter  2.0mm
1952 pin length 7.30mm  diameter  2.9mm

[jstin2]

Now getting back to the original topic. I can now see why my carbine with a 49 cover could actually be a 50. I could see that at refurb they would replace stock ferrule, for a new stock and probably replace 90 degree gas port at same time and if eyelet latch was broken, replace it. Now as I mentioned earlier, I checked to see if barrel was bottom pinned for a spike but it was only had a  top groove for a blade stock ferrule. So they didn't replace stock ferrule. Strike one. If at refurb they were going to replace 90 degree gas port, it would have to be done before the newer gas port came out (unless done in 50). Strike two. Original eyelet (49 and early 50) latch pins look pretty strong and doubt if they were damaged often and my 49 has the later 50 pin. Strike three. Serial number also takes into effect and I am out. Okay I am humbled, but there are a few iffy 49s out there with these features. And I can't see why they would change covers? And yes I know, nobody knows what went on at refurb.