I am using a 300 gr XTP eather a 44 or 45 Cal with 100 gr of 777 or Pyrodex and a 209 primer out of a Rem.ML 700. Ether bullet or powder combo. groups about 2-3 in. at 100 yd. My question is how many gr. of loose powder can be safely loaded? I know my gun will handle 150 gr. of pellets but have never seen anything about how many gr. of loose 777 or Pydrox it is proctical to load.