While shooting the other day I had fired around 150 rounds of TZZ 230 ball. Occassionally I would feel the slide sort of pause and then move forward in sort of a sling shot motion, this continued on and off for the next 50 rounds. Prior to shooting the pistol a 1911A1 Springfield was clean and lubed well and I lubed it again after the first 100 rounds. The recoil spring is a standard 16 pound factory spring. A friend of mine suggested that a heavier spring should be used with a steady diet of 230 ball and recommended I replace the 16 pound with a 17.5 pound. So I would appreciate any and all input on this.