On five separate Woodsman Match Targets (Series II and III) I have experienced the problem of the slide not locking back on the last round. I tried over a dozen mags (including brand new ones) and still had the same problem. I finally resorted to replacing the recoil springs with Wolfe recoil springs and that resolved the problem every time. Once the recoil spring was replaced the problem was resolved no matter which magazines I used (old or new).