I received the picatinny rail bracket yesterday that will accept tactical shooting lights on any hunting gun..As stated before it affixes to your front post swivel stud...It's awesome.. Even has an stud for you to affix you sling too. Any tactical lights that you can affix to pistols and or shotguns that need to slide on to a weaver type mount...This is what you need...
The shotgun light holders this company sales that affixes to the barrel is also outstanding too...
Any tactical light without a rail can be affixed as your shotgun shooting light...You won't even need a pressure switch...Just make sure that the 1 inch light has a push button on the back of the flashlight....Also give yourself some room to push the button too..In other words don't affix it to close to the forearm of the shotgun...
http://www.ambientsw.com/gs60100.html