Depending on configuration, 6-13 rounds.
The Springfield Armory 1911A1 manual states that +P ammunition should only be used in firearms with barrels of at least 5".
You can buy ammo SDU's from the ammunition vending machines, they will increase the max ammo capacity, and grenade capacity. Depending on how far you are in the game, you will be offered the green one, purple one, or orange one, which increase the maximum capacities to new levels.
what kind of pistol is it?
22 caliber ammo
if it's a revolver......32 cal revolver ammo if it's a pistol......32 cal pistol ammo
gun shows, custom ammo makers
any 45 cal ammo will work in a 45 cal pistol
yes
yes
NO
No
A 22 caliber pistol holds a dose of 22 caliber ammo.