Weapon changes for 17th century game

[IcarusWulfe]

So I've been working on a Pathfinder campaign for a while now with the setting and technology taking ques from 17th century Europe. I was thinking about implementing a couple of changes to a few weapons, specifically firearms and blunt weapons, that would keep weapons more in line with their historical counterparts and the setting's lore.
The changes I was thinking of making are
1. Firearms ignore non-metallic armor at any range, but metal armor still works normally(or maybe at half effectiveness within the first range band)
2. Firearms ignore deflection bonuses to AC (lead is anathema to magic in this setting)
3.Bludgeoning weapons partially ignore armor (historically, war hammers and the like were used as anti-armor weapons)

So, are these changes reasonable? Am I overdoing things and screwing up combat immeasurably?

note: I am using Spheres of Power in place of Vanican casting just in case its relevant.

[Grod_The_Giant]

I would try to avoid messing with things too much. For a 17th century game, I think I'd make two main changes:

Use the "Commonplace Guns" rule, perhaps going so far as to make most weapons (at least straightforward pistols and muskets) simple. Drop the misfire chance altogether. This makes commons common and reliable enough for a time period where they were the dominant weapon.
Use something like 3.5's Defense Bonus (http://www.d20srd.org/srd/variant/adventuring/defenseBonus.htm)alternate rule, possibly combined with "Armor as DR" variant. This lets you have people running around without giant suits of platemail... and neatly sidesteps of "armor beats guns" issue. It gives you a reason to avoid actual armor without making it useless against half the attacks you run into.