Trapdoor Rifles

Does anyone know when the government started surplusing 1868 springfields out after adopting the 1873 Springfields? I’ve read of 1866 Springfields in civilian hands as of 1868 and I’ve heard references of .50 caliber “needle guns” being used in the buffalos hunts in large numbers but that could be any .50 caliber trapdoor I imagine. Was the 1868 present in large numbers on the plains in the 1870’s- 1880’s in civilian hands?

IIRC, some .50-70 rifles (I think M1868) were sold/issued/given to the Union Pacific Railroad for protection of the crews building the transcontinental railroad in 1869.

FWIW, Frankford Arsenal was still loading .50-70 Benet-primed as late as September 1882 (only HS known for that round) so they must have had a need for them. There are some references to people such as teamsters, packers, and other back-water troops being armed with .50-70s, so they were not ALL released to civilians too early at least.

Decades ago I read in an article that said during the Spanish American War, Florida and Wyoming were still using 50-70 ammo in their state issued trapdoors.

So these guns were most likely reserved and not released for sale to civilians? I know Buffalo Bill used an 1866 Springfield as did wild bill Hickok I believe, but I suppose they were both scouts and could get them from the government do to working for them, not to mention being an earlier obsolete model. I’ve seen pictures of native Americans with 1868’s but I suppose they could have been scouts too. I’d love to see an add somewhere from that era selling them on the civilian market. I know state militias bought and held onto the old .50/70’s well after the .45/70 was established. I swore I had read that the .50/70 trapdoor was the most common rifle among buffalo hunters vs the sharps and rolling blocks everyone thinks of, it got me wondering how that could be. Thanks for all the insight! I live in North Dakota near one of the oldest forts here. I have seen lots of .45/70 405 & 500 grain bullets dug and even a .577 British or Canadian centerfire cartridge but zero .50/70 which is surprising.