I did some testing and pistol phantom is applying 20 stacks of bleed always.
While sword/focus are random (crit chance based).
EDIT: Pistol is getting 100% crit because of the last update that chanced the duelist fury to aoe. The pistol phantom is getting fury from it and since focus 5 is not an atk, it do not proc fury, thats why I got less crits from focus.
This is the reason I started to think, why not pistol when its clearly easier to apply a lot more bleed stacks. Since sword is melee only and the phantasm can miss and focus is random target (adds can eat some dps).