For your consideration one Columbia, SC arsenal bullet listed in Thomas RBRF4 page 195 bottom right. You will find this bullet to be in excellent fired condition. The patina is a thick, slick, light brown color & I do not see a single patina. Notice the long base stem*. In the right light both grooves can be seen. Measures about 0.51 x 1.105 inches.

*Seems this bullet type comes in a least 2 variations. The one listed in Thomas has a base stem (tie ring) much like an old pattern ringtail Sharps. Its also the easiest of the 2 to find & often has a blackish patina from being dumped into the Congaree River for 150 or so years. Then the one listed here at TennesseeLead.com, Much harder to find & the base stem does not look like a tie ring to me. Just a few of these bullets made it out to troops, this one did & somebody also shot it.