I'm personally not a big fan of Powerbelts as I've had difficulty in getting them to group consistant in several different rifle and load combinations.

That said, there are scads of folks that are shooting them with good results. The general consensus is to stick with the heavier powerbelts. in .50 cal 295gr, 348 and so on.

The lead or copper powerbelts will equally work just fine and you should not see copper or lead fouling before 50-100 shots depending on your charge. When fouling does occur, then a brass brush and some good solvent and your back in business.

A powerbelt is also considered a conical.

A good conical is really effective out to 150yards with the right charge combination.

Back before powerbelts and sabots. All I used were large conicals or patch and roundball for bigger game. Killed several dozen deer with them.

If cost is an issue and/or you like to shoot more often, then consider a pre-lubed Conical on top of a lubed felt wad.
They are also easy to load.
A decent conical will really lay the lumber on larger game. I also use them for small game with lower charges.

No Excuses Conical Bullets (50/$20)
Hornady Great Plains Conical Bullet (20/under $10)
Ox-Yoke Wonderwad Felts (50/$5-7)

Good luck!