The damage is 1d10 for pistols, and 2d8 for rifles, but I think the Proficiency should be revised, though, to be ranged martial. The mroe I think about it, the more I want to have higher damage rather than increased attack bonus.
Muskets aren't overly accurate weapons.
I agree, but remember a to hit bonus is more important then damage. I do think that 2d8 is a little high for damage for the rifle. Mainly cause very few weapons get 2 dice of damage, and it can be unbalancing when you talk about powers that have 2,3,4, up to 7 (W) damage. If you don't mind the sugestions, I have a few. Keep the weapons Superior (as it should take a feat to be fully trained in using guns), drop the to hit bonus down to a +2 (that way it won't feel like such a bite on a PC's to hit ratio), keep the pistol damage the same but change the rifle to 1d12 and add something like High Crit or Brutal (Heck if you can add both by the rules, do it) That way it doesn't break damage potential but still gives the guns some kick
Isn't Brutal in Martial Power?
If so, I can't use that Damage code. Nothing from Martial Power is covered in the new system reference document.
Damn, I wasn't sure if it was covered or not, but I think high crit is players guide. I'm sure there is another effect that fits you can add.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.