I shot gen 3 and 4th as duty weapons. But I am curious about the mag release different sizes, how much difference is in oem in complex frame like glock 19,23,etc. standard frames glock 17,22,31,vs the large frames 21,41. I know the MARS looks huge on a glock 19 gen 3, looks like one cm longer than the oem glock 19. That's what I wanna experiment with. But 59.99 to order a MARS is too expensive, not knowing the length difference or the position of the notch where the spring goes into