When first introduced however, the notable firearm expert Townsend Whelen noted the .32SL cartridge as displaying similar ballistics as the .32-40 Winchesterblack powder, low-pressure cartridge. He further suggests the best use of the .32 SL as being for rapid-fire target shooting for ranges up to 300 yards. Within such ranges, it is quite an accurate cartridge.
In October 1940. an Army Ordnance circular suggested development of a light rifle using a .30 caliber cartridge similar to the "Winchester Self-loading Cartridge, Caliber .32" to replace the pistol and submachine gun. This led to the production of the "Caliber .30 SL, M1" cartridge directly based on the .32 SL in February 1941 and, after a design competition, adoption of the Winchester-designed M1 carbine in October 1941.