MK40 Elite 98 premature slide lock

[cherryriver]

I think I saw this topic somewhere else here, but could not find it with the search tool.
I just acquired an MK40 Elite 98. It now frequently goes to slide lock prematurely, sometimes almost every round in a magazine. When I first got it, it did the same but less frequently, maybe once every eight or ten rounds.
I and a shooting friend have both tried it with similar results. Holding the right thumb (we're right-handed) down carefully to eliminate contact makes no difference.
Ammo tried includes Winchester white box, Blazer Brass, Winchester Ranger PD, and Speer Gold Dot.
If this was a 1911, I'd be thinking of filing the nubbin on the slide stop where the bullet's hitting it. The fact that it seems to be getting worse does not necessarily support that conclusion.
Any clues that don't include spending fifty bucks to send it to Kahr?
Thanks
Bill

[ChefBob]

It's probably the slide stop spring. Had the same problem w/ my MK9 and also thought it was the slide stop being nudged by a round as in a 1911, but a call to Kahr cleared up the mystery before I got my files out. Dottie sent a few extra springs and has run perfectly since then. Bob

[cherryriver]

The call to the factory produced a new slide stop and slide stop spring that was overnighted to me instantly.
I put the parts in Sunday and it ran perfectly for 100 rounds.
This certainly strikes me as a very well-made gun.
Bill