When you add length to the magazine tube of the 930, that is where a good portion of the malfunctions originate. Shell surge is a thing and since the 930 does not release the next shell on the trigger pull, but while in recoil...not a good combination and well outside of the engineered operating window.
Shorter extensions will obviously cause less issues, as will using a better, or even a HD magazine tube spring. I recommend and use Nordic Components tubes, nuts and springs. There HD spring is good for about 1000 rounds in a 7-8 round capacity. Their standard spring is good for about 1500 rounds, but it is not as strong.