Speaking of familiar, these 2 canister rounds are known to many forumites, but were reconstructed by Dave Gotter who lives near Mansfield.
The left one is for the 18pdr and is made of parts from Vicksburg, where there was only one 18pdr, the famous "Whistling Dick" cannon. This one was discussed here before when it was incomplete and in parts.
The one on the right is a 24pdr made up of 100+ 1.05" balls. This is not per regs which prescribed larger diameter shot, but we had one from Charleston like this. I got it from Greg Craven and it was mostly complete but still in water. It largely fell apart, but the wood sabot is being conserved now, and I look forward to someday pairing it with this round.