Yes, when you are working up a load swabbnig between shots will increase consistancy and give you better accuracy for the most part. Also it helps in the loading of the next projectiles as well. Before I hunt, I do like to shoot and then reload on a dirty barrel and see where that one hits as well. Just in case I really needed a very fast second shot. But even out in the field it is not uncommon to swab between shots. You can get these alcohol swabs at the dollar store, which you can swab with. Some people make up a small container of pre-wet patches for swabbing. The important thing is after a lightly damp patch you swab with, use a couple dry ones and swab with them as well to make sure the bore is dry, before loading again..

Personally if I had your rifle, I would forget the powerbelts and use the projectiles for what it was made for. Shockwaves and a powerful load is the Encore load on almost every hunting program I watch. Most of them are shooting 3 - 50 grain pellets and a Shockwave. Some of the distances they are shooting game at still amazes me. Other really good projectiles are Parker Extreme, Nosler Partitian, Speer, Hornady, and Sierra.