I have one HKocher, and I go to Wash U. Problem is, it's at home in IL, and I won't touch it until next weekend. I'd have to check to see if the batteries are still good. It will work in .223 and .308.
What I use it for basically is a starting point for zeroing my AR (and the Mini-14 I used to have). I go to my basement and put my gun on a sandbag. Then, I chamber the round (which is the laser boresighter), and it shoots out the laser against the wall. I then zero my irons or scope against this point.
Basically HKocher, it's good for taking care of windage. This saves time at the range in my opinion, assuming your gun won't shoot 3" right or left away from the axis of the barrel. You'll only have to worry about elevation in theory.
Oh yeah, I tried this outdoors on a cloudy day at 25 yards....couldn't see the damned laser light, which kind of made me POed.
themao