I just finished building an MP5-40 parts kit on a Vector V89-40 reciever. When I finished up and went to the range to do the shakedown run, I couldn't get it to feed. At all. When I drop the bolt, the round starts to feed forward, but it doesnt start to funnel into the chamber. Instead, it feeds straight forward out of the mag into the side of the barrel at the breachface. This happens with enough force to mash the bullet back into the case 1/16" to 1/8". At first I thought that maybe I was sold the wrong magazine with this kit, but after doing some research I understand that the 40, 10 and 357 MP5's all take the same mag. (My mags are both no name black plastic things.)
I looked at a factory Vector the other day. The feed ramp (or maybe more rightly called the "feed funnel") was opened up a little wider than on my barrel. I want to make sure there are no other options before I start taking material off the barrel. Any suggestion where to start?