We carry the necessary products that you would need to mount a flashlight on the bottom of your shotgun.
For the gun that doesn't have a lower picatinny you will need the UTG Universal Single-rail Shotgun Barrel Mount, 3 Slots.
http://www.westernmetal.ca/shooting/utg-universal-single-rail-shotgun-barrel-mount-3-slots-mnt-br003xls
After you have attached the picatinny you have two choices of mounts. This model is rigid.
http://www.westernmetal.ca/shooting/utg-angled-offset-low-profile-ring-mount-rg-fl138
This model has a flip to side function.
http://www.westernmetal.ca/shooting/utg-flip-side-27mm-tactical-flashlight-ring-rg-fl27qs
And finally you will need the 600 lumen flashlight. This model is made from hard anodized aluminum. It comes with the batteries (1 spare) and charger. The switch is located on the rear of the flashlight and has 3 settings (high, low, strobe).
http://www.westernmetal.ca/shooting/magnum-600-fl-600