Most here are not fans of Power belts or Pellets. Power belts have been reported to blow up on game if pushed to fast. 2 pellets would be more than enough for them but there are much better bullets out there that are usually much cheaper. The Price on the T7 powder is great and that would be a much better option, here on Long Island it runs about $28lb. Loose Powder is not hard to work (Be sure to get a good Volumetric Powder measure and bottle funnel) with and you can really experiment with the amount of charge to see what the rifle likes. Those Shockwaves would be a better option over those power belts, but I would not personally shoot them with the pellets and would get the loose T7 and start with at least 100 grains and work up. If they have any 300 grain Hornaday .452dia (45cal) XTP's (for Loading in Pistols) get those and some Packs of Harvester Crushrib sabots is a great cheaper option. Most don't like pellets for many reasons, 2 of which are that those boxes are not sealed and can draw moisture and you can't really change the powder charge in smaller increments.