I think your bullet is a Sharps, not a Gardiner. A Gardiner has a deep base, and is usually very easily noted by the ring at the base where a smaller piece of lead was used inside the paper cartridge to crimp it to the bullet itself.
A Sharps bullet is usually flat based, although they sometimes had a dimple in the base. The rings on a Sharps bullet are usually flat and wide, where a Gardiner is flat and narrow.
The toe tap is a nice find too. You may want to look around more, you could be just a stone's throw from a lot of relics. On the same token, you could have a hard search.
Good luck with it, and good luck digging!