Try P&D, Wholsale Sports or Russell's Sports they should have both, the 300 gr come in a 50 pack. I used the 300 gr XTP in my muzzleloader for deer many times and they work great. Just add the www's below.
http:// .p-d-ent.com/
http:// .wholesalesports.com/index.htm
http:// .russellsports.com/files/81-100hs06.pdf