I'd suggest Electric staff, due to how powerful it is w/spam and dmg.
Ask me anything and ill try my best to answer
As a owner of the cripple cannon, the Electric Staff is the best option for PK, but if you want a spar gun, go with the Cripple Cannon (even though it's more like a toy gun).
The reason that the Electric Staff is so good PK'ing is because it has a really fast fire rate and it's stacked (someone said before that the cripple is stacked, which is not).