TFoN, wiki this: "High Explosive Incendiary/Armor Piercing Ammunition". technically it does not mention them as shotgun shells, but then again thats a HEAP round, which is armour piercing, and SG's in real life are notorious for being useless against armor. then again, they dont have to be, as the spread will rip limbs off, even heads. also HEAP is for rifles, and other point-tipped ammo types. but you can see it has been done. and if it doesnt exist why is it mentioned in almost everything?
punching the cyberdemon to death is pure suicide. even if u had all the bonuses, and lots of meds, and lots of armor... ull never get close enough. his rockets knock u back a space always, 2 usually, i think ive even seen 3 spaces of knockback at point-blank! the closer u get, the more likely he will hit, and the farther back you will get pushed! pure suicide. even if u used the chainsaw!
oh... i had a revelation on the whole special ammunition idea! if Doom 2 had the shotgun, and then the super shotgun, which are basically the same thing, except double the damage and reload time, then why not alternate ammo?