Few notes -

Some years ago I hit a red-tail hawk on the left windscreen of a 707
at 16,000 ft climbing out of Houston. Made a mess - no damage. If we
lost windshield heat, our limitation was 250 kts below 14,0000 ft.
Guess that bird didn't know he shouldn't fly that high.

Also some years ago, I saw a Gulfstream that belonged to a Middle
East head of state at a US repair facility with a bullet hole that
entered in the belly and went out the top. They flew it normally all
the way to the States The Gulfstream carries a higher pressure
differential than any airliner I know of with an 8,000 ft cabin at
51,000 ft. and usually cruises about M .82 on long flights.

Aircraft pressurization is controlled by how much air gets let out by
the outflow valve/s. With a small hole or two, the outflow valve/s
would automatically close a bit and the aircraft would pressurize
normally anyway. If you do a ground pressure check on any aircraft,
they leak all over the place anyway. In flight it would just whistle
a bit louder and that's all.

Forget the pressure vessel as far as I'm concerned. What about those
rather large wire bundles being fed by a couple of 120 KvA generators?
Ask Swiss air. How about the primary control system, hydraulic
systems, or 20,000 gal of fuel? Fuel; ask TWA/ American. What would
happen if that 9 mm went through the fly-by-wire boxes on a B-777 or
Airbus? Don't know that one yet, but I hope we never find out.

Myself, I'd be just as happy if they'd leave the cockpit door locked
and used the crash axe if necessary. Besides, I know some of those
guys that fly those things and there are a few I wouldn't want to see
with a gun!!!