Bought my son an M3 for Xmas. Also bought IR filter (for a ridiculous price..) He complains that the IR filtered light is barely visible via NVG and that light 'leaks' from 'O-Ring' that 'seals' filter. The retaining catch on the lens is monstrously 'stiff' also. Is all this normal/acceptable?? Should I be complaining/looking for refund or is this the 'performance' one expects?? Appreciate any input. <font color="red"> </font>