The FF grains are too coarse for sidelocks. Even the FFF is coarser than any FF powder around. I think APP better suits inline users. That's only my opinion thou - so take it with a grain of salt.
I shot better than a case of 2f and 3f APP or/ Clean Shot with no problems.
Powder was used in TC hawkins,renegades 12 ga and 12 ga cartridge.
At one shoot I fired 60 rounds and never cleaned the bore.