A Few Thoughts
Anime Kidd said:
o Damage is based on the caliber and if using either blackpowder or cased ammunition. Lowest is 1d6 and the higest is 2d8.
2d8 is too high for a rifle or a pistol of the period you're considering. That's twice the damage output of the crossbow and longbow. I'd go 1d12 maximum. Also, don't forget that the DMG (pp. 162-164) already has some firearms rules.
O A list of modifiers to shooting. Weather, firing position, wind speed, aiming, target size, and a miscellaneous listing.
Most of these modifiers are already accounted for in the game. For example, weather mods are in the DMG, and target size is already calculated into AC.
O Reload times from 3 full rounds to 1 full round.
3 rounds is too much. Rate of fire for a Civil War era rifle is about 3 shots per minute. Use a full-round action for reloads. This gives the shooter 5 shots per minute.
O Armor Penetration: Reduces any Armor bonuses an equal amount.
This is a bad idea. Contrary to the widespread misconception, a Civil War era rifle isn't any better at penetrating armor than a clothyard shaft fired from a longbow.
O Firearms and melee attacks
Not sure what you mean by this, but here's what it made me think. (1) A Civil War era pistol is not a ranged weapon really. It was much more likely to be used up close and personal (i.e., melee range) before the soldier went to a more conventional weapon, like a bayonet or sabre. (2) Firing a rifle while threatened should provoke an AoO.
O Feats (Quick Load, Fast Draw, Called Shot, Imp. Called Shot, Crack Shot, and Dead Eye).
Don't get too redundant. If a new feat is just an old feat with a new name (Fast Draw = Quick Draw?), just use the old feat. Regarding Quick Load, I'd have it weapon specific (like Weapon Focus) and reduce loading time from full round to move equivalent.
No bonuses to attack roll for scopes. Apply the scopes magnification as a divisor to actual range to get effective range. For example, a x3 scope sighted on a target 300 feet away allows you to treat the target as if it were 100 feet away for purposes of range penalties, Spot checks, et cetera.
Also, while firing with a scope, the shooter should lose all Dex and dodge bonuses to AC.[/QUOTE]