Hodgdon purposely "toned down" the strength of the T7 pellets to closely approximate the Pyrodex variety. I think their purpose was safety as well as making the transition easier for pellet shooters. Figure the cost of a weighed pound of either powder's pellets vs loose powder and, after you pick yourself up, go buy some loose.

Loose powder comparisons will yield a different result - considerably different. T7 is much more potent and will deliver significant velocity gains for equal volumetric loads of similar granulations.

For the sake of your shoulders, I would suggest no more than 100 grains of loose powder for any tests.

T7 has its pluses in that cleanup is a bit easier and it is more energetic but the hardness of the fouling and the problems that creates make good ol' Pyrodex a better choice for lots of uses.