We have received couple of questions regarding our selector's seemingly ease to flick out of Fire/Safe. We hold very tight tolerance on our selectors, as anyone knows, this can't always be said of other parts on the AR, especially cast or plastic parts.
The following are our initial findings re: detent spring tension, pistol grip and their effect on the perceived stiffness on the engagement/disengagement of the selector.
Detent springs aren’t created equal, just the two I happened to have on hand are of slight different lengths. One of them is about 1.5 coils longer.
Pistols grips (USGI, Magpul MIAD, Tango Down Battle Grip, etc.) aren’t created equal. The part we are interested in is the depth of the detent spring housing/hole. With the same spring inserted in these three (USGI, Magpul, TD Battle Grip) grips, the spring seats deeper in the USGI than Magpul MIAD and TD Battle Grip, by about 2 coils.
Can spring length make a significant difference? Depends on which spring and which grip are being used. A shorter spring inside a USGI grip will yield less spring pressure on the detent, than a longer spring inside a MIAD or TD Battle grip. I was able to test and verify this. A shorter spring inside a MIAD or TD Battle Grip doesn’t feel significantly different, but without precise instrument to measure the pressure, I’d say one can hardly feel the difference.
The difference of a shorter spring + grip that seats the spring deeper, and a longer spring + a grip that seats the spring just right, is noticeable when the selector is rotated out of Fire/Safe.
Short spring + USGI = sloppy feel, less positive click, easy to rotate out of position
Longer spring + MIAD or TD Battle Grip = more force is required to rotate out of position
Pictures to come.