Well, there's this anecdotal evidence that says that a compressible filler (Dacron being one of them) can lead to chamber ringing. The theory goes that the Dacron can compress, leaving a void between it and the bullet. When the powder charge goes off, the Dacron strikes the base of the bullet and upsets it somewhat. A few times of that and the chamber gets a ring around the mouth of the case.
I'm not aware of anything approaching research and it's one of those subjects that seem to get some folks riled up. I don't use any fillers at all, so I can't comment one way or the other.
Well we don't rent pigs and I figure it's better to say it right out front because a man that does like to rent pigs is... he's hard to stop - Gus McCrae