I am trying to mount a light on my 870 (18" barrel, 6 round mag). I have a Surefire 6p with a TacStar pressure switch, but I need a good bracket to mount the light under the magazine. The ones I have seen are flimsy looking clamps that, if tightend too much, would actually crimp the mag tube. I'm looking for something a bit more substantial. Any ideas or products you can point me too would be appreciated. Thanx.