K31 woes

[smle-man]

I purchased a Swiss Products muzzle brake and took the rifle to the range today to give it a quick try.

I shot it first without the brake



Then with it



Recoil was noticeably less with the brake and the accuracy potential enhanced. If I hadn't been hurrying, I could've shot a tighter group.

The woes started around round 12 when the bolt wouldn't come back. It was stuck but good. I had to use the boot to the handle to get it open and once I did that it didn't want to go forward very far. A close look showed a crack in the bolt sleeve that also raised a spot that stopped the bolt from going past the bolt stop.



I had read that some wartime bolt sleeves had an issue with cracking and now I see it to be true. All of the bad sleeves were supposed to have been washed out of service over the years but you see how that went..

If your sleeve is marked Cn you are good to go. If not, it's gonna crack eventually.

[SVT-40]

That sucks. Are replacements available?

[smle-man]

That sucks. Are replacements available?

I found one at Apex. The on-line picture didn't look very nice cosmetically but if it works, it's good.

I wonder if the crack in the sleeve could be welded and smoothed so that it would function?

[FeuerFrei]

I'd try another part and forget repair. Heat treating disparity and other unknowns.

Good accuracy out of that old girl! She's a shooter that deserves a second chance at life.

[five.five-six]

Did you check your spent brass for cracks or bulges?

[TKM]

Check with Latigo for parts.

[smle-man]

Did you check your spent brass for cracks or bulges?

Yes, they are fine. A shooter on the Swiss forum on Gunboards has the same issue in the same place with his wartime K31. It is an interesting place to crack since it is a radius and shouldn't be under particular strain but that where it apparently happens.

[five.five-six]

I don’t presently own a K31 but I love that gun. Good luck with your repair.

I still have a few hundred rounds of 7.5 Swiss.

[Dan_Eastvale]

Did anything like this happen with any US service weapons back then?

[smle-man]

Did anything like this happen with any US service weapons back then?

There was the M1 rifle receiver heel breakage that I can think of for WW2 era U.S. small arms.

[FeuerFrei]

Did anything like this happen with any US service weapons back then?

03 Springfield had a low SN range that had brittle receivers. http://m1903.com/03rcvrfail/

[Latigo]

Good afternoon, gentlemen. I should be checking the board a little more often. I did have a gentleman asked about a sleeve, but unfortunately we don't sell of our own parts out of the Swiss products Armory, however if you are looking for parts, these are the places to go. BTW, a cracked bolt sleeve isn't all that unusual. If none of these contacts have that bolt sleeve, contact me on the Swiss products helpline. It's at the top of the page on our website

Apexgunparts
libertytreecollectors
gunpartsCorp.
Alwayscollectible.com
everygunpart.com
Schludershots.com
cogunsales.com (expensive)
Edelweiss.com
cogunsales.com
libertytree.com

https://www.gunpartscorp.com/gun-manufacturer/schmidt-rubin

https://www.schludershots.com/gun-parts-by-model/swiss-military-gun-parts.htm

[Latigo]

I forgot to mention, it's definitely not a good idea to try welding a cracked bolt sleeve.

[smle-man]

Thanks, I found one at Apex and it is installed already. I did find the Cn stamp on the cracked sleeve which surprised me. I managed to bend the LHO getting the locked up bolt open, so I'm going to have to use a hydraulic press to get it back in alignment. I can't see how I had enough power to bend that thick piece of metal but I did!

[flatbedtruckin]

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