My son is in South Carolina working storm damage and found this today while setting a pole . Just trying to figure out how old it is .

Do you have a caliper to measure the diameter? .54? .58?

looks modern

I agree. It looks like a 38 semi wad cutter. When the snowbank at my house melts in the Spring they are everywhere.

Definitely from a brass cartridge given the cannelure. Ive metal detected for gold in California motherlode and have found many old musket balls and more modern projectiles from both pistol and rifle. The musket balls are neat but I leave them lay.

old bullets tend to have Large grease groves

once tumble lubes became available grease grooves started getting smaller and going away

Looks like a 350 gr Speer or Hornady copper bullet