The HK-91 is a great gun (I have a PTR-91 and am now mostly satisfied with it, mostly) but I do not believe it is an appropiate weapon for home/property defense in anything other than a decidedly rural environment. Even with a hollow point round you are still looking at some serious over-penetration, particularly as the hollow point will fill up with dry wall, bits of plastics, clothing, blood, tissue, etc... If you fire a 308 rifle in an apartment, expect it to do some serious over-penetration.
I keep an AR-15 near my bed, with a mag of hollow points loaded in it, but I only plan to use that if I have to fend off people who have managed not to go down from 16 rounds of 9mm Hydra-Shock, and I only plan to fire at a downward angle so that if it overpenetrates it just goes through them, or through the wall and into the grass outside, or it goes into the basement where nobody is... Basically the AR-15 comes into play if I need to fire from the top of the stairs, down, at whoever is at the bottom or trying to come up the stairs.
The only time you'd get me to use a battle rifle or a carbine for home defense would be if I had nothing else, or if the enemies were very numerous or wearing body armor. If a half-dozen gangsters were to crash into my house, you can bet your rear I'd have that AR-15 chambered and engage the first one to the upstairs with the rifle, ending his crime spree with a 75 grain hollow point.
Sounds reasonable to me.
