It is a "modern" bullet and I doubt you could get 10 cents for it sadly enough. Don't know who told you it was from a 1st generation colt, but that would be hard to prove, and if it were it still would have no real monetary value. Most of all the old muzzle loading round balls and slugs we find have no monetary value. Rare civil war bullets do have values, but after that period they are basically worth nothing to anybody but the finder. I melt all old bullets I find down for fishing weights.