A Congressional document published shortly after the war may answer a couple of questions regarding ammunition for imported arms. This document (House Misc. Doc. 152, 40th Congress, 2nd Session, Serial #1350) purports to cover all the guns and related items owned by the U.S. in 1867, and although it's a post-war document, the Union wasn't buying anything from overseas after 1864, so the items listed must be Civil War purchases or fabrications. The doc is divided into vertical columns, one of which is headed "Quantity in the hands of troops" and the other "Quantity at armories and arsenals." Under the heading "Cartridges for rifled muskets" we find more than 300,000 "Elongated ball, calibre .71" rounds still in the hands of troops (with another 440,000 stored at armories and arsenals), and under the heading "Cartridges for smooth-bore muskets" we find more than 600,000 rounds of "Buck and ball, calibre .71 and .72," in troops' hands, with many more (along with .71 and .72 caliber round balls) in storage. Note that these are entirely separate listings from the usual .58- and .69-caliber loads, also shown herein. Under "Cartridges for pistols" we see 3700 rounds of "Lefaucheux, army, copper, calibre .46" in troops' hands (with another 1-1/2 million in storage), and also a listing for "Lefaucheux, navy, calibre .36" rounds, with 17,000 in storage. (Below this is a listing for "Pocket pistol, metallic" rounds, presumably .22 rimfires.)
Hope this proves to be of interest.
Hope this proves to be of interest.