SKS inconsistent blueing on receiver cover

[flying_scotsman]

Is the underside of the dust cover also discoloured?

 

[Longshot84]

Good question!! I'll have to check in the morning

 

[dand883]

I think it's softer metal where it gets stamped. The ends hardened where you need it.

I have heard that before, that they intentionally leave it softer it the middle so it's easier stamping. Of course I heard it on the internet, so it must be true right?

 

[MapleSugar]

Now...does anyone know where to find an SKS crate like in MapleSugar's post??

Where do you live?

The importing dealers will have them. Canada Ammo and Lever Arms come to mind.

IIRC, Lever Arms used to give them away. Now, since they've gained popularity, I think most dealers sell them.

It helps to live near one, shipping would be a killer.

Edit: Lever Arms is selling them for $20 now.

http://www.leverarms.com/products/russian-sks-crate-empty

 

[agentcq]

Re roll stamping. I have a couple that are not stamped but still have this same discolouration.

PlinkyPlinker is correct - letter series rifles that are not stamped on the cover have the same discolouration. I had forgotten about this.

 

[fdr]

Some Russian books on repairing firearms describe two methods of bluing: heat bluing and chemical.
I have a theory this could be caused by chemical bluing, when the cover is submerged in solution down first one side, then the other.
For example: Babak, Repair of hunting firearms, 2006.