Ok, did some comparing, and here are some energy comparisons all at 100 yards..

12ga Sabot slug 385 grain 2400ft/lbs
30-30 170 grain 1900ft/lbs
30-06 168 grain 2600ft/lbs
.375 h&h ultra mag 300 grain 4178ft/lbs

Again, just my opinion, but I think that if you are using anything other than the .375 (not recomended for deer sized animals) the delivered energy would be the most in a slug, as the nose is flat, and going to deliver more energy, as opposed to an easier, less resistant pass through with a rifle cartridge. Again...just my opinion, but I would like to see actual data on energy delivery formulas, as now i am just curious.