Naw, just get a Colt 1911 .45 caliber. pretty reliable gun. Just the remotely occasional "stovepipe". The .45 has great stopping power, -- almost twice the 9mm. You hit a hijacker with a .45 or a .40, he's going down.
Does'nt matter anyway, the public still thinks we "need to stay up in the cockpit where we belong". I think the public's perception is that we'll put on spurs and do the ole Clint Eastwood routine down the aisle. Oh, and a bullet penetrating the side of the plane will result in some wierd, cosmic physics reaction where people get sucked out and papers fly around.
The reality we all know is that one pilot flies, the other sits there with the muzzle pointed at the door. What's so hard about that?
As usual, we pilots are the only ones who knows anything about how pilots operate.