He needs to be bigger. Remember, Owen is HUGE and yet he describes franks as the same size or bigger.
Maybe somebody from a super heavyweight division of MMA, like a Brock Lesnar, or Overeem, or Frank Mir...
Its hard to capture in a still photo how freaking huge Brock is/was.
Maybe holding a 50cal like a Rem 700 will do it.
Wikipedia says his bout weight is ~266lbs. My guess is that he was cutting a lot to hit that target.