BoxOtruth did a piece on the judge. In short, the slugs did about as well as the .45LC, but buck out of it was found seriously lacking. It did not have the energy required to penetrate to (let alone through) vital organs at a range of about two yards (IIRC). Federal supposedly came up with a new round for the judge in .410. It supposedly had one small slug backed by several buck shot. I haven't seen any testing on it, but I reckon the slug's energy is reduced greatly by its small weight, and the buck probably the same as results for just buck.



Edit to add: The testing a buddy of mine and I did with a 3" judge in calibrated gel got 3" of penetration with buck, and 14" with slugs at a range of 4 yards. FBI minimum to be considered an effective round is 12 to 18". Also always remember that unless specifically specified otherwise, energies advertised by ammo companies for revolvers are tested and figured using six inch test barrels.