I swapped the original safe-semi-auto, selector in my M16A1 with a KAC ambi selector.  Now I don't get the typical solid 'click' when I switch from safe to semi.  Semi to auto feels correct.

I believe the cause is that the long leg of the autosear spring, as it is pressing on the top of the selector, effectively smooths out the transition.  I'm talking about the spring leg that is on the serial number side of the receiver.

I don't see a remedy to this, unless I have the autosear spring leg in the wrong place.  If I remember correctly, it won't fit behind the selector because the leg was too long.

Make sense.  What am I doing wrong?  I'd like to get the crisp click back.