Marsupial Gear makes small and large holsters that have a snap. The small fits Glock g19 and smaller handguns. The large looks like it's for medium frame revolvers. It snaps right over the waist belt on my pack. I didn't want to trust a snap to hold my gun, so I backed up with a loop of amsteel (actually zingit I believe). There's loops on the back of the holster that you can feed that amsteel through. That way, if I comes unsnapped then the amsteel loop catches the holster. I've used this all season and it works great.
The small fits my Kahr CM9 and also S and W M and P 45 acp.
Always stay protected by attaching your semi auto handgun to the bottom of your binocular pack with our our quick draw holster. Attaches to the bottom of our packs with MOLLE WEBBING.
www.marsupialgear.com