I was curious if you or anyone you know actually uses an AR-15 as a home defense gun.
(snip)
Basically, is an AR a reasonable choice or outright loony for such a use?
A semiauto .223 carbine (AR, mini-14, Kel-Tec, whatever) is an eminently reasonable HD choice, in my opinion. A 9mm is more likely to be on my person or close at hand in an emergency, but the AR in the safe wears a light and has a magazine of JHP inserted, and would be my first choice if I had time to access it.
What about your hearing if you shoot an AR in a room without hearing protection or a can?
Same as if you shoot a short-barrel centerfire handgun in a room without hearing protection or a can; you'll probably suffer some mild hearing damage.
A lot of people forget that the peak loudness of a firearm is roughly proportional to the bore diameter and velocity
and inversely proportional to the barrel length, so a 16" or 18" barreled .223 carbine is no louder (in terms of peak dBA) than a lot of 3.5" or 4" barreled pistols, and is considerably
less loud than a .357 revolver (thanks to the high-pressure annular discharge at the barrel-cylinder gap).
http://www.freehearingtest.com/hia_gunfirenoise.shtml
The sound spectrum (and possibly the pulse duration) are different between centerfire rifles, pistols, revolvers, and shotguns, but the peak loudness is surprisingly similar.
ALSO, pardon me if this has been said but God forbid you need to use it, what do you think the jury of non-gun owners is going to think of your evil black rifle?
We have some data on that, from something of a "worst case scenario."
http://www.thejuryexpert.com/2009/0...s-and-the-fears-of-the-legally-armed-citizen/
This study involved a scenario that was intentionally ambiguous (shooting an apparently unarmed guy who is trying to walk out of your house with your VCR, who makes verbal threats but no aggressive moves). There was
no statistically significant affect on the innocent-or-guilty decision between the mini-14 and the AR-15. There
was a statistically significant affect on sentence length for those defendants who where found guilty murder, with slightly longer sentences going to the AR-15 users who were convicted than mini-14 users who were convicted, although the gender of the shooter played a larger role than the weapon choice.
So it appears that mini-14 vs. AR-15 doesn't make a difference one way or another as to whether a jury will rule justifiable or not, BUT if someone is convicted of murder, they may be sentenced somewhat more harshly if they use a nontraditional looking firearm.
I think that now, with the "assault weapon" fraud going away and the AR-15 dominating both the centerfire target shooting and home-defense carbine markets, the small dichotomy that existed in that study will become even less significant as time goes on.
I'm no lawyer, but it is my layperson's opinion that the choice of any practical NFA Title 1 firearm (whether handgun, rifle, or shotgun) would be much less important than things like the homeowner's demeanor, aggressive posturing prior to the incident ("trespassers will be shot" signs, that sort of thing), intoxication, and whether the homeowner was engaged in illegal activities at the time. I would expect that factors undermining the components of justifiability, i.e. imminent jeopardy and the mantle of innocence, would take precedence over the aesthetics of the firearm itself.