Looks good as far as the shape but it's lacking a lot of that chalky white patina we see on aged lead. There is some present but it doesn't look as thick as others I've seen. Possibly a more modern muzzle loader?
When I first picked it up it was really white and and I thought it was a rock, if you want to see it when it first came out watch this video, it's around 1:10 in the video.
Ok, I watched the video. Good job! This is my WAG:
Because you found the lead on the ground, and modern clad near the surface, I believe it is a fairly recent muzzle loader round that should date to around the time of the most recent coin.
But as I said, WAG.