HK HK HK HK HK HK HK .. U.S.A Hidden Content
I own three NIB HK's. Doubt that set's any records around here but I like them and they won't stay virgins for long.
P2K 40/357/40T RCM tube
P30L 40/357 RCM tube/40T RCM tube
VP40/HK 40T tube
Some old steel AK parts are like this. I like it. Nothing wrong with it, just a unique cosmetic thing. Likely due to metal heat treating and/or the bluing solution used at the time.