Variables
Howdy max,
Apart from initial hand-cycling and two test rounds per spring rate, (16.5 and 18.5) I haven't had a chance to wring'em out in proper fashion yet.
They seem to be lighter at the beginning of the stroke than a straight rated
spring of the same loading, and the resistance stacks up quickly as the slide moves. At the end of the stroke, they feel like they're actually a little stronger than the standard springs, but that could be a manufacturing variation, and not representative of all variable springs.
They worked well on the two-round test fire, with the 18.5 pound spring
producing noticeably snappier recoil than the lighter spring...which is
also true of standard springs.
'Bout all I can tell ya right now...
Luck!
Tuner