[Slono]

I replaced the upgraded recoil spring with the stock spring and it still gets stuck about 90% of the time, except the slide gets stuck a little farther back. The slide catch is almost at the slide catch notch where the slide can lock back. The weird thing is that the mag is never empty when that happens so it shouldn't go back that far.

And like with the upgraded recoil spring, once it gets stuck, any space between the receiver and slide becomes so tight that there's almost no movable space. Its like something along the rails are forcing them together. I examined the rails but everything is completely flat.

Edit: I can still slide it back and forth even when it feels really tight and there's a point where if I move it fast enough with force or forward enough (nearish to resting / battery position) OR back enough (nearly fully cocked back), something makes a clicking noise and I can feel something move or change within the receiver. Once it clicks it slides smoothly again. Is this a rail misalignment or something to do with the hammer assembly?

Hammer assembly = all the little pieces that work together to move the hammer.
If there's a specific name for those pieces I would like to know so I don't have to make names up or use the wrong ones.