The 1886 is a 40.86; one of the original 5 calibers. I have a confirmation from Winchester that the gun shipped from the factory around 1895 (I’d have to find the confirmation to get the exact date).
The Colt is the US 1861 Army Model, 44 caliber. It was the model issued to the Union forces during the Civil War. The 1851 Colt, .36 caliber, was the Navy Model.
Now you’re confusing the heck out of me. The Cartridges of the World lists a 40-82 that they say was for the 1886. There’s no mention of a 40-86. It’s listed as obsolete but they recommend you buy .45 basic cases that can be cutdown.
As far as the Colts go, according to the Flayderman guide, the 1851, of course was in .36. They then made the slim framed 1860 in .44. They followed that with a copy that looks exactly like the 1860 but called it the 1861 and chambered back to .36.
You’re very fortunate to have originals. I can only afford replicas. I have to be careful though, since a lot of those Italian “Replicas” never existed in the first place.