My shield 9mm was tight and not just the recoil spring, but fit of slide to frame, etc. Jammed initially and S&W replaced extractor. Still jammed and then I shot more and racked slide a lot and it now seems to be working properly.

As others have mentioned the recoil spring is strong and force must be exerted to retract slide fully. While recoil spring will loosen a bit with use, the tight fit on some guns will definitely loosen up with use.

For uses where I want a slim gun and/or one with safety the shield fill a need for me. But for general use I like a glock 26.