this is my first time make my own lures. Ive never had any dealings with injection molds. I made a shad body injection mold at work other night and when I inject it the tails fill out nicely but almost all the bodies are hollow. Sometimes the tail will fill then nothing in the body and the sprue will be completely filled out. like I said ive never done anything like this before and have actually never seen a injection mold before. m sprue is 1/4 diameter. My Im thinking it could be vent problem only vent I have is in the tail. I burp the injector before I shoot so I don't think that's the problem. thanks for any help