Need help with bullet id

[bearbqd]

Not sure if this is the right thread to post in for this but I need help with a bullet id. I braved the cold on Sunday for several hours and went to a field that has produced many civil war relics. I'm glad I brought my Eastman geologist pick with me or I wouldn't have been able to recover anything in this frozen ground. That sure was fun--NOT. Anyway, didn't find much with the corn stalk remnents, and a lot of snow still on the ground. The only reason I found this bullet was because it was so close to the surface.
Anyway, not really sure what type this is. It looks similar to a colt .44, but it has an oddity. It has a small conical base (#13 cavity type in the Civil War Projectiles II book). Of all of the bullets in this book it looks the most similar to 488 and 489. The are from a Colt Dragoon-early model or colt revolving rifle. But as far as I know these are solid base, which mine is not.
The ones in the book are .464 and .453 in diameter. Mine is .452 and .806 in length. Any idea?

[vayank54]

Most of the colts and watervliet arsenal bullets had solid bases Some did have cone shaped cavities. I don't know if this was due to different manufacturers or what. I've dug a few of both with the cavities in VA. I guess you have Mason and Mckee's bullet book. It is a good book but there are bullets that aren't listed in there. I've got a couple that aren't listed.