I have a 616 and a 320, both accommodate a filter. I don’t use the filter, nor the adapter. They’re all sitting in the boxes. I think the draw is damn near perfect with nothing in there. But I smoke cobs a lot, so I’m used to (and prefer) a fairly open draw. Like @chasingembers said, you can fix a draw that’s too loose with your packing. You need a drill to fix one that’s too tight.