I don't know
, he said it does it with factory ammo too. That's what threw me. I can see the re-loads making him have hiccups but not the factory ammo. I think it's not an ammo problem but I'm in no way qualified to suggest a fix.
I was going to suggest that Dave will probably diagnose it for him
On the rare occasion that I have a failure to return to battery with my re-loads, I can just bump the back of the slide with the side of my fist and it goes into battery.