WinchesterX150

I got my 255 grain maxi hunters in today, which was super fast. I already had the gun loaded with a powerbelt so i fired that off @ 50 yards and took a look and it was about an 1 1/2" to theleft, gotta adjust it over a little. Next 5 shots were with the maxi hunters and 60 grains rs @50 yards. First shot 3" to the right, second shot, right into the same hole. After 3 shots and finding them all in the same hole i was thinking i was missing the entire target so i loaded up #4 shot and aimed to the left a hair and sure enough, right next to the other 3 shots. #5 shot i aimed back to normal and noticed the One hole was smudged a little to the right. 4 out of 5 shots directly into the first shot. I was out of maxi hunters so i loaded up 2 more 225 grain powerbelts and took 2 shots and these hit directly in the bulls eye but 1" apart. Even though the maxi hunters shot flawlessly im still not sure which bullets i will use this season. If i decide to use the maxi hunters i will need to adjust the front sight now, my rear is hanging a little to far over as it is.

Now the problem. I keep busting 2 caps and always on the #3 cap i have to put a little powder in the nipple to set the charge off. Im getting rid of this nipple and possibly dumping the whole entire #11 cap setup. Do any of you know what size threads the deercreek rifles used? I tried a couple out of my cva's and the threads wont work with it or the entire base is to big.