When I posted my DCC character sheet, I mentioned that the boxes for abstract ammo tracking would probably be implemented in manner similar to Brendan’s suggestion in this post: After combat, every character using a ranged weapon rolls 1d6; on a 1 they lose a quiver/level of ammo. I prefer this sort of simplified ammo tracking because it eases bookkeeping and ties in well with the “Significant Item” encumbrance system. Plus ammo in the DCC rulebook is priced as bundles anyway (i.e. 20 arrows for 5 gp), so the math for buying one level of ammo is already done for you.
I’ve decided to tweak the post-combat ammo check ever so slightly — after combat, a character using a ranged weapon rolls 1d10 and loses a level of ammo on 3 or lower. The percentage chance is hardly changed, but it keeps things mechanically consistent with another simple mighty deed I’ve come up with. This one is definitely still in the tweaking stages. For one thing, I’m thinking about changing the damage dice to -1d. As always, I welcome feedback.
Rain of Arrows: A warrior armed with a long bow or short bow lets loose with a frenzied volley of arrows. On a successful deed, the warrior rolls a number of damage dice equal to the result of the deed die and divides the total damage evenly among the target and every other living being within 5′ of the target. The attack roll still must be a hit for any affected creature to take damage. However, even creatures that are not actually hit are still counted in the division of the total damage done if they are in the area affected. Regardless of whether the deed is a success, after the roll the warrior must make an immediate ammo check; if the d10 roll is equal to or less than the number on the deed die, the warrior then loses a level of ammo.