Howdy to the camp,
I have been researching the .46 short rimfire that was used in the first conversions of NMA 44s for the Army in 1869ish. UMC had a loading of 227 grain .456 diameter bullet with only 20 grains of powder.
The Winchester load, however, boasts a 230 grain .456 diameter bullet with 26 grains of powder! That is just shy of the .45 Schofield with 27-28 grains of powder and a 230 grain .454 bullet, and for that matter, the US Army standard reduced .45 Colt loading of a 255 grain bullet with 30 grains of powder.
I image that the effectiveness is close to the same as they Schofield. I can see why it might have been very popular. For my Uberti gated conversion and Uberti forged frame with conversion cylinder I am going to duplicate the Winchester load with .45 Schofield brass. That is about as close the original rimfire as I can get!
I am working on some period type labels for both loadings that will glue onto Pioneer products Schofield boxes. When I am done, I will post as an attachment ot a new post.