Round for round.<quoted text>
Really? You think a sawn-off (a Westinghouse, wooden stock shotgun with a 2-cartridge capacity) can cause more damage than a high-capacity, fully-automatic AN-94 with .38s? What planet are you from?
Even if you upgraded your sawn-off to a banana clip (which you'd have custom-made for a few thou), you still wouldn't be able to out-perform a double-cyclone canister clip that's available either custom-made or available in the standard market for a number of upgradeable guns.
Yep, the guy in that link turned an AR-15 into a goddamn LMG. Your sawn-off ain't shit, bucko.
One round of 3inch magnum 00 buckshot vs one round 223. Do the math.