Large Sidearm Pocket is an ammo gear perk that greatly raises how much sidearm ammo you carry. It keeps pistols and other sidearms fed through long fights.
You carry far more spare ammo for your sidearm. You can rely on it as a main weapon without running dry.
Good if your sidearm does a lot of the work, such as a silenced pistol for stealth. Otherwise skip it.
Disrespect, which steals enemy sidearms, fits a pistol-heavy style.