Hi guys. I was wondering if you could give me some tips on how to repair my ZCI 509mm 6.02 R-hop tightbore barrel. Story is that BBs disperse everywhere even when I am firing in semi automatic. What would you think it's the problem? I took it to a repair shop and they said they "fixed it" when the dang thing still shoots like cràp. The people whom I bought it from won't even bother to answer the phone. So at the moment I feel screwed and I dont know what to do. Any tips/suggestions on what I could do to repair this supposed to be "awesome barrel"?