A couple of basic questions first:

Does the gun jam with factory ammunition?
Have you cleaned the rotary magazine? Does it revolve smoothly?
Have you checked the feed ramp for any dings, dirt, or obstructions?
If, as it appears, you're are using reloads, what bullets are you using? Hollow points sometimes hang up.

If I had to make a quick guess, I would suspect the rotary magazine spring.