So I went down to the safe and pulled my old SLP to see if i can help. There is a cone type spring under the back end of the shell catch. This spring pushes out in the back of the shell catch therefore moving the front in and releasing the shell. If the spring is broken , missing or just weak it will not be able to push out on the back of the catch. I do not shoot the SLP any more switched to a Browning A5 and this spring has to be changed on those guns almost right out of the box to feed with a extended tube on them. I believe I got the spring for the Winchester SX2. All those guns have the same design, and it is easier to find the parts for the Winchester. Brownells should have them.