Won't stay on the gun - SureFire XC1 Ultra-Compact LED Handgun Light

I bought this for my Glock 29 thinking that Surefire would have designed a solid product given their track record. Every time I shoot my gun with the light attached it falls off within 1 or 2 mags. I tried tightening the bolt that holds it on to the point where it broke. After I got a replacement bolt and made sure it was tight before shooting it again to no avail. The light fell off again. Now I'm stuck with a $260 gun light that won't attach to my gun. I can't return it since its been more than 30 days and Surefire won't do anything for me. They just tell me my Glock rail must be out of spec which I don't think is the case. Regardless, this light should have been designed to hold onto any glock rail regardless of any minor differences. Very disappointed in Surefire for this product.