I've tested and owned a SIG P250, P320 and P226.

I only kept the P226 and found it a nice pistol to use. It does not tend to shoot to point of aim though and some aiming off may be required. I think that may be because it is set up with light non lead pellets at the factory. That said, the pistol does shoot consistently.

I would also consider the pellet firing Glock 17 - the triggers are very heavy to start with but do wear in after a few CO2 cartridges have been fired through the action. I found that mine does shoot to point of aim.

I also have a Crosman PDM9B, which is a pellet firing blowback clone of the Beretta 92, which is a pleasant pistol to use. I almost sold that one and ended up withdrawing it from sale as I remain quite fond of it.

John M