[Tramonto]

...and all 12 gauge shotguns.

How many bbs are in bird shot? Its going to be expensive to have every little one stamped with a serial number.

[relictele]

These proposals (if true) are comedy gold. It’s like having blind people develop the traffic code.

[PasorBob]

How many bbs are in bird shot? Its going to be expensive to have every little one stamped with a serial number.

My sixteen gauge slug gun must be safe since it won't be included.

[PasorBob]

How many bbs are in bird shot? Its going to be expensive to have every little one stamped with a serial number.

My sixteen gauge slug gun must be safe since it won't be included.

[SJSAMPLE]

Google “taggants”.
Small pieces of firproof “paper” that encode the lot of the propellant.

They have something very similar for Taser cartridges. When the taser is fired, serialized pieces of paper fly out to mark the scene, and identify the taser cartridge serial, leading back to the buyer/owner.

Same thing could be mandated for factory-loaded shotgun ammunition.