So I just bought a used kwa kmp9 and it will only shoot a bb every 10 cycles. When I pull the trigger, it makes a quiet pop and the bolt cycles, but not all the way. It also doesn't shoot a bb when it does this. Occasionally, I will get the gun to make that loud crack when I pull the trigger and it does fire a bb, but that is very rare. After continuing to troubleshoot for a couple hours, I found that the cylinder was cracked. Is this the cause of the problem, or is it something else? The seal under the cylinder was also clear. Isn't it supposed to be orange? Is it a knock off gun? I'll also mention that the gun is about 3 years old, and the previous owner lived in chilly Washington. They said it wasn't used much though. I'd really like to know before I purchase parts and pay the hefty shipping charge. Thanks!