Has to work longer than 5 min - Crimson Trace MVF-515 Modular Vertical Foregrip Laser Sight For AR-15 Rifles

I took my mvf to the range and had to sight in my new eotech and 3x magnifier as well as cowitness my back up sights. I fired 15 rounds with huge gaps in time between them to sight in my red dot. After that I was going to sight in the green laser on my mvf only to find that I could not get the green laser to come on ANYmore. After only 15 shots. The laser wasn't even on during that time. After I got home and looked closer the laser was coming on but it was so faint you could barely see it. I changed batteries didn't help. I took it apart and reassembled no help. In a cqc situation I do not believe I want to be worrying whether or not the 600 dollar laser I bought will work. Asking for a refund. Get a sure fire instead.