+1 on what Buff said. My 317 will start getting hard to extract after about 30 rounds...by 50 rounds its almost unworkable. So I typically let it sit and cool and then wipe under the extractor and over the recoil shield with a CLP soaked rag. It then runs fine for another 30 rounds or so. I have come to consider this normal operating procedure for this gun.

I did have a spent case bulge enough to tie up the cylinder once. The bulge was at the primer end of the case directly across from the firing pin. This locked the cylinder up tight. I quit using cheap Remington bulk ammo and its never recurred.

Maybe I am misunderstanding your problem. Any chance to see some pictures of the bulged cases?

Would definitely make it easier to help with figuring the problem you are having.