I have had the STS come slightly loose on my Shadowcat and mess my groups up, then just lately I have twice had the rubber stop move, just a tiny bit, but enough to touch the string a little early and again it affected accuracy.
So, I just took it off completely and chrono'd the bow; all good at just a touch under 300fps, but all landing a little high. A tweak of the sight had that sorted and I then shot seven arrows (six at spots and one at a 3D) and got the most consistent results, since starting to shoot this bow.
My question: Is the STS just a gimmick? Or does it work well for you?
I like the way it stops all the rattle and buzzzzz (huh! should try one on my 1989 Lynx, now that bow rattles!), but if it's affecting consistent accuracy, it can stay in the spares box.