I have a Bushmaster M4 clone and while it's a pretty gun, good and fun shooter, it's one of the less practical guns I own at least for things like home defense and hunting. It's better suited for what it's intended for. Actual combat..or LE use. Or rat hunting. <img src="/forums/images/graemlins/smile.gif" alt="" />
I personally would not want to use any rifle round for home defense, unless you live on a Ranch, very rural area or have lots of property. In an apartment or neighborhood setting, there is just too much chance of a round over penatrating and hurting an innocent bystander or God forbid should you fire and miss, the round could easily leave your house and travel across the street and right into someone else's bedroom.
I personally know of at least one case where some idiot was cleaning an AR15 and a round killed his neighbor next door in an entirely different house.
To get an idea of much penetration a .223/5.56 will do, check this out. It will slice right through 12 sheets of drywall and 12 3/4 inch Ponderosa Pine boards. In other words, the walls of your and your neighbor's house don't have much of a chance.
http://www.theboxotruth.com/docs/bot1.htmThat doesn't mean that I won't ever use my M4 for self defence, outside of work or the woods. There's one place at my house where the backstop is a concrete wall and it happens to be a building behind my front door. So I would feel safe using there to stop an intruder, but still not practical for most home defense applications.
The AR-15 is a very nice shooting gun. It's fairly light, has almost no recoil and is very easy to hold, shoot and aim accurately by novice shooters, so it has some major advantages. It's definately a fun plinker. It's one of the few guns my wife actually enjoys shooting. But ammo is not cheap anymore.
Come to think of it, price of ammo is getting damn right outragous these day. <img src="/forums/images/graemlins/angry.gif" alt="" />
Anyway, if limited to the three choices, I'd probably pick 9mm, since it would the the safest of the three for home defense.
