Okay here's my idea is to make a class that uses the crossbow as a main weapon and only shot once per round. My problem is that PF inset really built for this sort of thing. So the damage is going to lag behind a lot if I use the normal rules. So how do you think is a good why to fix it?
I think this class should be a (sniper) that shoots people from a far and uses stealth and other skills to get in shooting position.
I think I'm going to make it a archetype of the gunslinger. Or is there a better alternative or should I make a totally new class.
I want this class to be able to comped with other range attacker with damage and I think it would be nice with some fun ability's.
I think you're looking at a crossbowman (http://www.d20pfsrd.com/classes/core-classes/fighter/archetypes/paizo---fi ghter-archetypes/crossbowman) with vital strike as feat.
if you are going to use tha archetype I would take 9 levels at least in crossbowman, then add in some 3 levels, maybe 4 for anothe talent of rogue Sniper
You would be living on readied attacks and sniping, but in tehroy it would work
as many have pointed out crossbowman is not the best archetype.
Unless you are really dedicated to using a crossbow, the gunslinger class has a built in ability,Deadshot, that does what you want except with guns.
In your situation I would just use the gunslinger class, perhaps with the Musket master archetype, but with minor flavor tweaks and have it focused on the "crossbow".
If you try doing it with actual crossbows you will always be incredibly far behind on damage.
I do like the idea of using gunslinger...if i was your dm i would let you use a crossbow, and make some kind of modifications. Crossbow is not a touch attack, so iwould give you some other bonus. Maybe give you sneak attack at a slower rate (1d6 at 1st, 2d6 at 5 etc) or something like that, or maybe give you some of the archetype abilities of the crossbowman archetype that arent terrible
Crossbowman/Sniper would have excellent opportunities. There ARE sniping mechanics in the game, which is what you'd want to take advantage of to be a one-shot, one-kill. Sneak attack damage and other forms of extra damage dice such as weapon enchantments, etc...are going to be key.
Stack on feats, abilities, and spells that give you cover and concealment, or better yet, invisibility, and use the other feats for things that modify and boost your single shot.
Just beware of Entropic Shield and other similiar, low level, simple protections from your One Deadly Shot.
The best idea is definitely above, using Gunslinger mechanics for a crossbow. After all, you can take many ranged weapon feats with a firearm, why not the other way around?
There's also that one wizard archetype....was it Spellslinger? Maybe a neat option for big booms.
Two levels of Master of Many Styles monk to pick up Kirin Style and Kirin Strike to get double your INT to damage. Then just go into the Crossbowman archeype for Fighters and take typical crossbow feats + Vital Strike / Devastating strike tree. Eventually you'll have your Dex to damage, Double your INT to damage, deadly aim, and be dealing 2-4d10. Your readied actions will be the bane of all casters. Make sure to grab items that let you see invisibility so they can't screw you in that regard.