Looking for assistance in designing a crossbow

[Wonky Chewbacca]

I'm currently writing a level 1-2 adventure involving an ogress wielding an uncommon crossbow that I have tentatively titled the Arbalester. This is a particularly bulky heavy crossbow (possibly with more bulk than normal), that one could crank the windlass an extra time (as an action) after it's been reloaded to deliver an extra punch. My thought was something in the neighborhood of a pushing or knockdown effect, but I'd appreciate any thoughts as to what might be an appropriate level of power on a level 2 or 3 item, along with pricing suggestions.
I imagine one could slide the balance one way or another by stipulating whether or not the extra cranking has to happen in the same turn you reload it.

[Pirate Rob]

Take a look at This from the beginner box.

[Wonky Chewbacca]

Nice! An excellent starting point. Gives me a nice benchmark to start comparing properties. Many thanks.

[shroudb]

maybe make it so that Crits do knockback normaly, and crits do knockdown if it was extra-winded for the knockback/knockdown aspect, similar to an alterante crit spec.

as for the extra damage, i say 1 action for +3 damage seems fair given things like precision edge (a class defining ability that in a lot of occasions is 1d8 for 1 action (plus all the extra for being class defining)) or stuff like Smite Evil (4 extra damage for an action with some upsides, but level 6 class feat)

+3 also aligns good with the item linked above (upgrading 1 to 1d6 is +2.5 on average)

[pendothrax]

Thunderscape has a carraway crossbow that grants a +1 damage for every extra action used after loading to further crank the winch, up to four times.
it is otherwise a crossbow.