I have a 56-50 Spencer with an unusual bullet profile.
The cartridge on the left is a typical 56-50 Spencer the one on the right has a different bullet profile (heavier bullet?). Physical dimension of the two are very similar. All of the military contract loads I’m aware of have bullets profile almost identical to the one on the left. The cartridge on the right, with the wider bullet weighs 497.6 grains. After weight all of my other military contract style 56-50 Spencer (CD Leet, DC Sage, Jacob Goldmark and FVV&Co.) their weights ranged from 456 to 475 grains. The weights of commercial rounds (UMC, USC, Winchester and Dominion) are all in that same weight range also. To my understanding the standard military contact 56-50’s all had 350 grain bullets and 45 grains of powder and I think commercial loadings were similar.
Any thoughts on this heavy bullet version, who loaded it and for what purpose?