Ok problem with mine was not the spring. Take a look at the top of my barrel.
the barrel does not drop low enough when the slide goes back. My gunsmith just smoothed this out and rounded the top inside of the slide where this was getting caught up. he said he had never seen this before. I sent this picture to Smith and Wesson and they said it looked like normal wear...................hardly.
I have about 1,000 rounds through this gun.
Now it is functioning fine, but I will keep an eye on this to see if it
starts to dig in again.
Take a look at the top of your barrel and see if there is a "ledge" being dug into the top of it.
If it's new and it's sticking tap the end of the barrel with a rubber mallet when the slide is locked back.
If it pops shut (like mine did) you may be looking at a similar issue as I have here.