Within the current iteration the following rules are in effect for Deyra:
Variant Emerging Guns: Firearms are mass-produced by small guilds, lone gunsmiths, dwarven clans, or maybe even a nation or two— and the occasional rare adventurer uses guns. Early firearms are available, but are relatively rare. Adventurers who want to use guns must take the Gunsmithing feat just to make them feasible weapons. Advanced firearms exist, but are rare and more difficult to create, requiring four times (4x) the price of what is listed on the srd. Modern firearms exist but are impossible to create without the Greater Gunsmithing feat. They also require sixty times (60x) the listed price. These price increases extend to calculating cost for the purposes of crafting.
Modern Explosives: Modern Explosives are allowed to be created provided the character possesses the Greater Gunsmithing feat, and at least 1 rank in craft alchemy. Modern explosives prices increase to four times (4x) the listed price.
Special Ammunition: While bullets are much harder to specially make, specific ones have appeared. Any Arrow or Bolt variant may be turned into a bullet variant at GM discretion.