Runnings in Dickinson, North Dakota (it's a large farm store whos sporting goods would rivel most gun stores here) had tubs of 12,500 rounds of .223 for $6,500. Listed as XM855BAR, 62 grain. Drum weighted 360 lbs. I'm not sure if they would ship but they had .223 ammo stacked waist high in a row 3' wide by 20' long in boxes of ever size. Lots of 17hmr, 9,40,45 and all the large caliber hunting rounds. They don't have any 22lr though.
Even saw bricks of 22lr for $35 each n Montana.