I never used SR-4756 until led to it by the late Ken Waters in one of his "Pet Loads" columns in Handloader magazine in the early 1980s. The article dealt with reloading the 32/20 WCF in revolvers, which are a cantankerous lot in general if you plan on hitting what you aim at with the loads. Mr. Waters' Pet Load used a 118 grain cast bullet (Lyman #311008 IIRC) atop 6.0 grains of SR-4756 and a small pistol primer. With bullets that fit the throat of the involved revolver, this load is MAGIC. In the Colt Police Positive Specials so chambered, I tone the load down to 5.4 grains (10% reduction), and the loads shoot very close to where the sights are looking. Likewise with the heavier loads in my Colt Army Special, S&W M&P, and Colt Bisley S/A.
The 32/20 WCF is one of those original black powder calibers that did not make the transition to smokeless powder usage seamlessly. That is a complex discussion not real germane to this thread's subject or evolved content, and I will take that up in a new thread later today. For the subject at hand--SR-4756 powder--I was very sorry to see the fuel get discontinued, and I have never used it in shotshell applications. The IMR shotgun and handgun fuels were never common in my area, Hercules/Alliant ruled the world locally--and still do. When In Rome.....well, NOW IMR is trying imitate Alliant with their new line of shotgun/handgun fuels that have followed the funeral of SR-4756. It IS the sincerest form of flattery, I suppose. A patent/trademark attorney might beg to differ, though.