Alchemical Cartridge wrote:
An alchemical cartridge is a prepared bundle of black powder with a bullet or pellets, sometimes with more exotic material added, which is then wrapped in paper or cloth and sealed with beeswax, lard, or tallow. There are many types of alchemical cartridges, the simplest being the paper cartridge—a simple mix of black powder and either pellets or a bullet. Alchemical cartridges make loading a firearm easier, reducing the time to load a firearm by one step (a full-round action becomes a standard action, a standard action becomes a move action, and a move action becomes a free action), but they tend to be unstable. The misfire value of a weapon firing an alchemical cartridge increases as listed in each entry.
Gray Dust Cartridge: (Source Heroes of Golarion pg. 18) wrote:
Packed with mysterious magic-suppressing dust from the Mana Wastes, these rounds burst on impact and inhibit spellcasting. When a gray dust cartridge strikes a target, it deals only half damage, but the creature struck takes a –10 penalty on concentration checks to cast spells for 1d4 rounds and cannot cast defensively.
No mention to the adjusted misfire value. How does this work?