Magazine spacer I didn’t think of that. Could now see how it might be hard to use the extended mag if you didnt have a flush fitting pug. Hope to see one in the market soon though. Keeps the dust and debris out of the grip space. All of mine get filled with hair when I’m behind the chair working.
Have you considered making one yourself, utilizing silicone glue/caulk?
Silicone is pliable when dried, easy to remove/replace if need be and could be applied to be flush, so it would not impede an extended mag.