I am posting this for reference, as I sort of hijacked a WTB page. I thought it might be useful in the future for someone.
These are British Military issue horns I have. The top three are marked with an issue number. The fourth is the type issued during the American revolution, which was really an artillery priming horn that was used until pretty much the end of muzzle loaded artillery. The last is a Percy Tenantry issue horn.

The first and third are nearly identical designs and are marked with a company letter and a rack number, so I think these two were used by one of the 95th Rifle regiment Battalions.



The second one is an upgraded version of a type used in the American revolution. The base is very similar to some used in that war with the non-metering spout like that used on the gunner's horn.
It seems to have a half charge measure, whereas the other two throw a charge around the standard 4 dram charge. I think this one was for a volunteer unit, since it only has a rack number, and being as a volunteer unit generally only had a single Rifle company, no letter would have been necessary. It might have been for a unit like the Duke of Brunswick Corps, which only had a single Rifle company. There were a plethora of volunteer Rifle units though.

Comparing the measures of the "volunteer" (lower) and "regular" (upper) horns.

Artillery gunner's horn used by rifle equipped troops during the American Revolution.

Original Percy Tenantry horn missing its locking spring though.

Hugh Percy, 2nd Duke of Northumberland' mark

Comparison of the original to the Rifle Shoppe castings.

Note the original was sheet brass, so a lot of thinning needs to happen to the casting.

It is also interesting that the horn's seem to have been carried with a short strap or chain. Perhaps it was locked around the cartridge box? Two of these have such a strap method and they seem original. I have seen photos of other similarly equipped.
Mike