Lost optic at the range lesson learned

Recently got a holosun 407k and installed it on my p365 x macro. I didn’t torque it to spec because I didn’t have a torque wrench on me but I screwed it as tight as possible. Went to shoot the gun and the sight for the first time and when I was about 5 mags in, the sight came flying off the gun. It landed about 5 yards down range and I told the RSO who told me I needed to wait until they closed the range to get it. When I called them back they told me they didn’t have it. Lesson learned… Guess i’ll be rocking irons for some time