I only have an 870 Rem in 20 gauge, so it's either the Keltec or my Dan Wesson .357, but in a pinch I have a Marlin Model 60 with the 18 shot tubular mag. A lot like 2 rounds of double 0 buckshot, but I have to pull the trigger a little more.

Or I could use the Mark II Target with comp. I actually did really well at an IDPA match course.
Jeff