K31 Cracked Receiver Help Please !

Hello...I bought a K31 Swiss Ricle and under close inspection I noticed it has a crack in the receiver, on the top...Can anyone tell me if this is dangerous to fire, how it might have happened or if anyone has seen anything like it before ?? Thanks a bunch I appreciate it !

---------- Post added at 03:13 AM ---------- Previous post was at 03:09 AM ----------

I apologize I forgot to include the pictures....

https://www.milsurps.com/images/impo...96a85343-1.jpg

https://www.milsurps.com/images/impo...05376f84-1.jpg

Are you sure it is a crack and not a scratch? I can't imagine what would cause a crack in the rear of the receiver. The locking lugs where all the pressure would be is at the front of the receiver.

That being said, if it is a crack, I wouldn't fire it no matter where it is on the receiver.

The photos don't really show if it is a crack or a scratch. It looks perfectly straight which would seem unlikely for a crack. If it is a crack you should see it going down the wall of the stripper clip guide. You can also wet it with a fast evaporating liquid. If it is a crack, it will stay wet where the surface of the receiver will dry almost immediately.

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Originally Posted by Aragorn243

Are you sure it is a crack and not a scratch? I can't imagine what would cause a crack in the rear of the receiver. The locking lugs where all the pressure would be is at the front of the receiver.

That being said, if it is a crack, I wouldn't fire it no matter where it is on the receiver.

The photos don't really show if it is a crack or a scratch. It looks perfectly straight which would seem unlikely for a crack. If it is a crack you should see it going down the wall of the stripper clip guide. You can also wet it with a fast evaporating liquid. If it is a crack, it will stay wet where the surface of the receiver will dry almost immediately.

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Correct ! I thought it was a scratch as well, but it sure seems to be a crack even though it's straight, that was the best pic I could get but it doesn't show where the crack originates in the corner of the slot....Although it seems unlikely it would crack at all that would be the place, in a corner like that to start a crack if indeed that is what it is for sure......I will try your liquid trick, and pull the bolt out and see if I can see the inside of the receiver in that same spot and see if the crack is all the way through, I imagine it would be ??

I don't know this sure is a mystery, I have never heard of this problem with a K31 and the Swiss built/build high quality rifles...

+1 using evaporating liquid. If it is a crack the rifle is no longer safe to fire.

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Originally Posted by WarPig1976

+1 using evaporating liquid. If it is a crack the rifle is no longer safe to fire.

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I agree, a crack anywhere in a rifle receiver makes it a bad idea to fire, but I wanted to be sure......Wha would you use for a quick evaporating liquid ?? I have carb cleaner,model paint thinner and nail polish (non-acetone) on hand....

Well I took the bolt out and can't see anything on the inside indicating a crack.....I used brake cleaner, carb cleaner, paint thinner and non-acetone nail polish remover on the mark and they all dried evenly so the rifle is ok I think....With the "what if" factor in the back of my mind though I highly doubt I will ever shoot it.
Thank you everyone for your imput and suggestions, I really appreciate it !

I doubt it is a crack but you are the only one that can make that determination short of taking it to a gun smith. The location doesn't make any sense for a crack, that section is simply a guide.

K31's are known to have a weakness in the bolt guide groove. There are examples of cracks in this area, generally forward next to the chamber. These are caused not by firing the rifle but by using the rifle as a step, stretcher, seat, etc. I've seen training photos of them using the rifles in this manner. The stress of the weight of the individuals on the center of the rifle are what causes the cracks. I suppose it is not inconceivable that a crack could occur at the rear of the receiver and that's why you should check it out very carefully.

Raven, You might try an NDI inspection shop. It could be magnafluxed or dye pentrate inspection checked. Some machine shops can do this. Also aircraft repair inastallations. Salt Flat

It looks like a scratch. You should be able to look at the inside corner of the receiver where the scratch/crack originates and see if the line extends downward.