[quote=@Silverwind Blade]
<Snipped quote by Slypheed>

Ditto, and plus there's a lot more choice. They don't get in the way as much either when you've got to wear all of that flight gear and then wriggle into a cockpit as well. 


[/quote]
iirc, survival rifles are tucked into a compartment under the ejection-seat.

They were developed pretty much due to the realization that bringing a pistol to a stand-up gunfight is a bad idea.
-Such as the GAU-5/A, with a nominal barrel length of 10 inches and a half-assed suppressor.
-Later replaced by the GUU-5/P (essentially a rebarreled gun, as they retained the GAU-5's full-uto giggle-switch)

'course that's survival-kit stuff lodged deeply into the escape-kit, and not really a "sidearm" one wanders around base with.
-Unless you're a hangar-sentry, ofc.
-Plus, this is the upper-limit of what can be crammed into that compartment.
--The upside is you generally get six or seven mags of tracer-rounds for it, pretty much a "No batteries required" means of directing close air support when pucker-factor reaches twelve. (here, having a range that exceeds "suicidally danger-close" and full-auto for CAS are good things)