First off befor I change the Powder I'd dump the CVA (Powerbelts) I take it that your using? Go with and this is My Opinion and I have always shot CVA MLers and through all of them I use in My CVA ACCURA's 240gr XTP Mags with either 2 50gr Pyrodox Pellets or 100-110grs of Pyrodox RS Powder. The results are 1" groups at 100yds and 2" 1/2"+- groups at 200yds.
Yes the T7 will leave a Crud Ring , did you swab between shots? that would help. Also the T7 Primers should be fine I use them also. Powerbelts are good for Target's but not so good on Game.
(BP)