Will Bison:I did some quick research in my limited library.
Fracsa & Hill, "The .45-70 Springfield" (1980), claim that Frankford Arsenal carbine rounds had "paste board" wads to take up the excess space (p. 235).
They further state that in 1886, the use of wads was dropped & the bullet was seated deeper to take up the space formerly occupied by the wads (p.236)
Waite & Ernst, "Trapdoor Springfield" (1980) state the same information & give the same dates (pp 159 & 168).
Your guess is as good as mine as the composition, dia., & thickness of these "pasteboard" wads....