Hey Everybody! I have a CVA Optima Pro and all the loads I've tried with this gun I get 4-7" of vertical stringing with successive shots. I've tried many loads - two different primers, two different powders, saboted and unsaboted bullets in various weights and I keep getting the same results. First shot will be on target and successive shots the POI moves up. My local gunsmith says this is due to the bore being dirty and I need to clean between each shot. This would make sense to me if successive shots were moving down, but they are moving up, which suggest to me an increase in velocity. Have any of you encountered this problem? how can I resolve it?