~16 years ago the late gunsmith and experimenter, Randy Ketchum, told me he put more and more 800X in a 200 gr 44 magnum and could not reach pressure sign.
~14 years ago I put more and more 800X into a 40sw 200 gr load and even got up to triple compression of the powder, and could not find pressure sign. The half burned flakes from the muzzle could burn holes in paint.
But in 32 S&W Long, 85 gr, I found sticky cases at the same top performance in 800X and LIL'GUN. The charge weight of the 800X was half that of the LIL'GUN. This exceeded the performance of other powders tested including H110.
Based on these and other experiments, I have modeled powders in (3) categories:
1) Linear: More powder, more pressure, more velocity. Unique, Bullseye, 4895
2) Peaky: More powder, lots more pressure. AA#5, Blue Dot
3) Fireballs: More powder, little more pressure. LIL'GUN, 800X, LONGSHOT
Quickload does not predict fireball experiments well.