I highly doubt that soldiers in the early stages of metallic cartridges were expected to handload any more ammo than are current soldiers. I've heard war stories first hand from different generations in my own family, with the earliest being my great-grandfather who served in WWI. Granted, he died in the early 80's when I was pretty young, but there was never a mention of collecting brass from the battlefield to reload. Nor from great uncle's in WWII, both grandpa's in Korea, cousins in Vietnam, etc...
Seems they were always kept pretty busy doing other stuff.
Actually after the civil war budget cuts caused soldiers to do exactly that. It's been documented and is what it is. Likely soldiers in the 1870's - 1880's shot more handloaded rounds than they did factory ones, because the handloaded ones were what they had more of.