New 4095 jams left and right

I recently purchased a 4095 from a gun show, and when I took it out to the range, it jammed almost on every shot (using Winchester 165 grain fmj rounds). It started getting a little bit better towards the end of the shoot, so I am wondering if it is just some sort of "break in period". Another worry is the fact that my friend who owns the exact same carbine had his trigger lock up and barely got it working again. Did we get bad ones off the line, or did we walk into a rip off situation and buy a crap gun?