I was 3 rounds inro my range session today (everything laid out perfectly, magazines stacked up & loaded, cool breeze blowing, no one at the range but me), when I'm suddenly grouping off to the left. I looked at my TRP (with it's tritium front sight, placed there by IWI no more than 200 rounds ago), and lo and behold, it's about to come off! Talk about raining on my parade.... So, I guess I'm taking it back manana, but what was the cause of this, most likely? Thanks in advance, geegee.