Sorry for the long delay…
I run 124 gr JHP’s (nukes and the previous MPR’s) with 5.4 gr. Silhouette, at 1.075″ and it gives me consistent chrono readings of 1050-1075 fps in my 4 and 4.25″ barrels.  
I could run them longer as some have mentioned, but this works in every gun I’ve ever loaded for and is a very soft shooting and controllable load.  Yes pressure increases as OAL decreases but 1.075″ fits most book data for 124 gr. JHP’s and isn’t considered “short.”