1/25 details

Some other things that might help, scale firehouse has a buncha tutorials, that aren't restricted to fire trucks but are extendable to all emergency vehicles, and some of them could even be useful for military modeling.

http://scalefirehouse.com/pages/tutorials.html

In addition somewhere on that website are documents which you can download and print out including caution tape, maps, handbooks, etc.  I can't find them right now on there.  I believe I still have them on my hard drive, if I can find them I'll PM you so I can send them to you.

G scale = 1/22.5 so you can find some model railroad stuff that will work for the basic stuff, tools, cans, flashlights etc. Some of the O scale (1/43) and HO (1/87) can work too, obviously out of scale, but sometimes works for a smaller version of the item. I used some large HO scale railroad car search lights for 1/25 truck mounted flood lights.

Your best bet and probably only bet is to look at accessories for scale emergency vehicles such as police cars.  Most copcar kits have shotguns, and there are other companies that produce shotguns and rifles.  Most usually Remington 870 pump shotguns, and AR-15 type rifles.  I believe a few of the van and truck kits from back in the day contained hunting style rifles as well.

Checking out the various gun forums and such, can net some nice pictures for easy scratchbuilding.  Although if you are anti-gun I would avoid those forums and stick with google image search if you would like to go the scratchbuilding route.