Has anybody had problems with powerbelt bullets. year before last i had to shoot my buck 4 times to kill. 1 hour and 15 min later it died. all but one shot was right on money. last year i shot nice 8 pt never found and also didnt find hardly any blood (few drops).i felt shot was good but i guess you never know.been shooting 100 grains but thinking of moving to 150. any advice on new bullet would be greatly appreciated.