I've been seeing a "new to civilian" trend and that's taking a 5.56 brass and stamping out the daylight hole in the daylight covers making it the diameter of the 5.56. I understand that this helps with autofocusing, "poor mans" Matblock Tarsier basically.

My question is if this small change in diameter will have a higher chance of causing permanent damage to the NVG tubes when exposed to stronger lighting conditions or if the change is so small that it is still enough protection when going in and out of dark and light areas in a CQB environment.

Thoughts?