I know 12 gauge is the traditional defensive shotgun caliber. For buckshot this makes sense, due to the increased payload of the 12 gauge. For a dedicated slug gun, does the 12 gauge still have an advantage? Looking at the data, it appears that 20 gauge slugs are lighter, but have higher velocities for higher overall muzzle energy.
I'm interested in a lower recoiling gun, plus the advantages of slug technology. Is there a reason to stick with 12 gauge?