[sticks.bcs]

Why is there green residue on the gas valve, piston, and gas tube? Is it copper being shaved off as it passes the gas port in the barrel?

 

[GoodGuy]

I've seen certain brands of factory ammunition use a bright green sealant around case mouths and primer pockets. It's possible that some of the green sealant is getting into the rifle's gas system. Check out your ammo to see if it has green sealant.

 

[sticks.bcs]

No green sealant. All my rounds have been handloads with sierra bullets and varget powder. The primers however are nickel red box Winchester small rifle primers. You don't suppose.............

 

[sticks.bcs]

I meant to say the primers are White box with red lettering WSR. The green that appears is the color of copper patina.

 

[digger440]

It just jacket material as you said in the original post. Perfectly normal,clean your rifle as you normally would and carry on..

 

[sticks.bcs]

Thanks Digger, I will!