Need Help with Bullet ID

[Drumfish420]

I dug this bullet out of a creek back in August and thought for sure it was a Burnside. Fast forward to Weds this week I dug another bullet about 50 yards away in the same area that I am also sure is a Burnside (or possible Spencer). Problem is the bullet on the bottom, while very similar, is taller and has a larger diameter than the bullet on the top. I don't have calipers, but I'd say the top round is .52 and the bottom round is .54 or .56. I initially thought the top bullet was a pistol round when I first found it. Thanks for any help!

 

[Nathan Stuart]

What is the approximate length of both bullets?

 

[UCVRelics]

The top one is a Spencer. The bottom looks like a Burnside but need some better photos and the measurement for determining the Cal. The Burnside came is 3 different types.

 

[Drumfish420]

Thanks guys, I'll try and get more pics up today and the measurements when I get home from work.