I recently bought a Yugo SKS 59/66. I fired it for the first time yesterday, and it stove-piped nine out of ten shots. Today, all ten. Last night, I disassembled it and checked the gas tube, gas piston, operating rod and spring, and everything check out ok. I cleaned it as well. I even went to the extent to order a new gas piston, operating rod and spring, just in case they might be worn out. Whenever it fires, the spent casing doesnt get out fast enough before the bolt moves to put another round in. I was looking at the spring mechanism for the bolt, and it has a sticky substance on it, like a real thick lubricant, but I don't think it might be cosmoline because it has no color. Can anyone tell me what could be wrong with it and how to fix it, or am I just dead in the water with a bum gun?