I just got the gbl on friday. Itching to go shoot it
H4198 and IMR-3031 are my favorite 45-70 powders for the Marlin 1895GS.
I have a plinking load I make with 405 grain cast bullets and Red Dot pistol powder.
Quickload predicts my max pressure around 39,900 psi which is in the safe range of Group II 45-70 loads.
Fired primers have lots of "round" left, easy extraction of fired cases and after firing measurements indicate minimal "brass flow" (case stretching in either direction).