Bullet Pulled Question

Close up of hands breaking open a double barreled shotgun and loading it with a 12 gauge shell. A shot and discarded casing gets removed from the chamber.

This sequence of shots shows how the bullet looks when fired from a barrel in various states. Top frame is from a hot/fouled barrel. The bearing surface of the bullet is visibly darkened by fouling, and there's very little flame/flash from the suppressor, as it had been fired numerous times and was filled with combustion products. Contrast this with the shots after cleaning. The first shot after cleaning leaves the bullet very clean, with very little fouling visible. This appears as a 'clean' bu