Save the powerbelts for quick reloads and second shots. If you can get the SSTs to work in your rifle, you will be much better off. The difference is very impressive.

I started off with powerbelts, killed 4 deer with them. On the firsttwo, I was marginally impressed with their performance, on the last two (same load and about the same distance) I was witness to the "exploding bullet" experience. In both cases the bullet went about halfway through a broadside deer at 70 yards, penetrated about halfway and fragmented. Exit wounds consisted of several holes from chunks of broken bullets. Blood trail was poor. Yes, it did knock them down, but not for good and while the deer would have died (the placement of the shots was perfect) eventually, they should have been nearly instantly killed. I don't even try front shoulder shots unless that is all that is presented, I shoot a muzzle loader more like a bow for placement; looking for double lung shots and a large blood trail. Just behind the shoulder and the double lung with through and through penetration is my goal. Ballistics, I used the 295 grain aero tips, also left something to be desired. As far as accuracy is concerned, I was not impressed w/ the powerbelts. Inside 75 yards they were ok, but not great and even then had occaisional flyers and inconsistant performance.

The SST style bullets have much better ballistics and the 6 I have killed have had increadable performance. That very tight trip down the muzzle apparently translates to improved performance in accuracy as well.
Getting them down the muzzle can be tuff though. A different sabot, as already suggested, might solve the problem.
So, when I hunt, the load in the gun is behind a SST. Once fired, I reload w/ a 295 g powerbelt because it loads fast and easy andgoodenufffor a "finish off" shot (which I have not needed w/ the SSTs, unlike the last two powerbelt shots).
All that said, every gun is different and you may have fantastic luck w/ power belts.
Good luck
Hank