"The military rounds were not black powder,"
.38 LC cartridges, at least those manufactured for military use by Frankford Arsenal, used black powder (15.4 grains) until early 1900. The last Frankford-made lot using black powder was loaded in late 1899 and early 1900. The very first BP loadings used 18 grains, which Army Ordnance later decided was too heavy. The only .38 LC loads using the heeled outside lubricated bullets were those early ones (beginning in 1889) made by outside contractors for the Navy and they also used black powder. From 1892 onward, all .38 LC produced for the Army used the inside-lubricated bullets. From 1909 onward, most .38 LC military procurements were made from outside contractors (USC, Peters, Rem-UMC, Win, and Western). Presumably, all those used smokeless powder.