Hi ckc123
the best thing as far as the "rules" go, is to go to
www.idpa.com and download the rule book, and if you have a friend or a boss with a laser printer, print it out. A hard copy is so much nicer
IDPA is spawned from the fact that over 35 states in the union allow CCW.
So the rules are made so that you mimic the "real world"
From the rule book: IDPA is a shooting sport that uses practical equipment, including full charge service ammunition to solve "real world" self-defence scenarios.
As far as the 3 gun match stuff....
Well, the big P in IDPA does stand for "Pistol". There are no rules for rifle or shotgun in IDPA.
Now having said that, as long as the spirit of IDPA is kept sacred, lets play with all 3. After all, if the big D stands for "Defencive", what would you rather defend your home with, a pistol or a shotgun/rifle?
I have shot one 3 gun (it was IPSC) before, and the biggest screwup is that people have the pistol part down pat, but they have never used their rifle or shotgun under stress. So when it come time to do a reload under the timer, they are all thumbs. Some don't even test their guns at home before going to the match, they get there only to find out something is broke or the sights are way off, ammo don't feed............I could go on.
So the best piece of advice I can give you is make sure your 3 guns work well, and you are comfortable with them, before going to a match!