I take Shinto Yoshin Ryu JiuJitsu and though there isn't a style sponsered emphasis on guns, my teacher insists on learning EVERYTHING that will keep one alive in extereme situations.
We do a lot of weapon retention and cross train w/ a Kuntao/Arnis master in knives and firearms retention.
Recently my instructor has been working w/ our Kuntao/Arnis friend in creating a training program for police and SWAT
my school:
http://www.sfama.com (still under some construction)
our Kuntao/Arnis friend:
http://www.tacsafe.com
The attitdue taken in my dojo is that we are training as warriors...not for fitness, not for spiritual awakening, but as warriors follwing Budo as a code (which does encompass mental, physical, as well as spiritual training in order to make for a more well rounded and stable warrior).
Hope that helps and is of some interest.