Rival S not consistently locking back on empty magazine
I have a new Rival S that I put 300 rounds through. 124 grain NATO so they had a little more oomph. I was hoping to break it in a little as when I first got a Rival I had some issues with the polymer one ejecting rounds until the gun was broken in. I switched back to my usual 124g non NATO round and had some issues with the slide not consistently locking back on an empty magazine. Do I just need to shoot more to break the gun in or is this indicative of an issue?