Is it possible to loot four horseman (Naxxramas)؟

Hi, so i want to get Armagdon http://www.wowhead.com/item=40343/armageddon but it seams the loot is bugged, every time that i kill 4 bosses i get no loot, is it possible to get the loot ? i mean is there any specific routine like priority kill or something ?

No.
The only way to obtain Armageddon in-game atm is from 'Gluth', but the drop chance is below 1%.

you can,its on marketplace. at least thats where i got it from