I have biten my tongue for two long and I don't know where Jdun is getting his information from.

"You can't bring your personnel sidearms from the States to another country. You have to buy the firearm from the country you are stationed and that can be very expensive. You can't bring the sidearm back to the States so you have to sell it before moving back."

That is a load of crap.

"You standout from the rest of the troops if you carry a personal firearms. Which can translate to more people wanting to kill you.
Special Force more or less can use any weapons that they are certified."

More crap.

"Unless you're an Officer, the guy that is dragging the machinegun, MP, manning/operating vehicles (pilots, tankers, etc), SF, or isn't issued a rifle you won't be carrying a pistol."

It all depends on what type of unit you are in and what the mission is.

"Pistol are defensive weapons. In the military pistols are issue to personnel that needs a weapon to defend themselves. Machinegun like the SAW are heavy, hard to maneuver, and jam often. They are issue a pistol for personnel defense. Pistols are issues to pilots and tankers because there is no room to store the rifles in the vehicle."

Again crap. Pistols in the military aren't just defensive. Many rear-echelon guys carry M16s in the supply trucks. Also pilots can be issued with SMGs and sometimes carbines not just pistols.