Of note all of this talk about guns and hexing is moot. For one qlawdat has clarified several times that the GM is ok with this concept. For two they aren't even playing in the same universe. It's possible that in this other universe there is no hexing, or that hexing effects cats and dogs. All of that is kinda up to qlawdat's GM isn't it?
Yes. Thank you. My GM does not care about any hexing happening to my guns. They are made specifically for gun magery, and are immune to hexing.
as to the dodge vs resist the way id do it is with 2 rolls for the defender. Id have them make an athletics vs your guns to get out of the way of the bullet, thus never being effected by the spell. If the bullet hits then id have them make a resist roll vs the spell (potion str). Endurance vs str for spells like fireball, discipline vs str for hallucinations, conviction vs str for mind control (If your a Law Breaker), ect ect. That way they can dodge the bullet itself and still have a chance to reduce the damage if actually hit by it. That would help in my game to reduce the damage down to a more manageable amount. Of course it could also skyrocket it if the resisting character has a low resist roll but that is no different then if a wizard uses a 8 refresh lighting bolt vs a character with no endurence... there gonna do a lot of damage. I'd also make you spend time in character building your potion bullets... of course the ones in creation are free but Id make you build the reloads. Also a failed roll might not mean that you dont create one. It might be a dud or a backfiring bullet... the compel options are very interesting that way.
Having the target roll twice seems excessive. The gun will fire the prepped spell/potion, but once the spell leaves the gun it will function exactly the same as the spell or potion. I do not want to be punished for having an idea.
I'm on Haru's side here. The gun is just fluff, making the effect weaker because the player decides to flavour it as bullet-based strikes me as awful.
Hexing shouldn't be a problem. It's just compels, and compels are not a bad thing.
As for the actual question of the thread, listen to computerking. His answer is correct, and if you care at all about optimization you should follow his afterthought and boost your Crafting strength.
PS: Be careful with the balance here; Crafting is possibly the most powerful thing in this game. Weapon 10 bullets and 10 shift maneuvers are impressive, but roughly on par with an equivalent amount of Refresh spent on other stunts and powers. The real worry is blocks and Thaumaturgy: a 10-shift version of Harry's coat can make a character incredibly hard to hurt while a 10-shift Thaumaturgical skill replacement can make other characters obsolete. And 10 shifts of Orbius can convince me to firebomb your house.
I didn't know you could use the Thaumaturgy to replace other skills. Interesting. I had also skipped the Orbius skill, and dear god is that powerful. Sheesh.