Yesterday I was shooting an older German made, Interarms imported, Walther PPK/S. I had no issues with slide bite, but it certainty didn't love the remanufactured 380 supplied by the range. It would choke on them every once in awhile. The gun has fixed sights, and shoots high. I would have to aim significantly below the target in order to hit it. For example, to hit a 2 or 3 inch target at 7 yards I would have to aim about 2 or 3 inches below the target, with no part of the sight being on the target. Once I corrected my aim to deal with the elevation problem it grouped quite well. Is this elevation problem typical? The sights are fixed so I don't see any way to adjust the elevation.

Bullet weight affects point of impact and unknown re-loads (Not to insult the remanufactured ammo used at the range. ) throw more uncertainty into the mix.
My Interarms PPK shot way high the one time I tried a 100 grain handload but hits point of aim with 95 gr. & lighter ammunition. Try it with other loadings before giving up.