What are folks using to adapt smaller diameter external mics to the clamp on the A1 short of using a different mount?

A few turns of Gaffers tape on the mic barrel to make it thicker?
Some sort of foam padding?
???

Hi Don, gaffer's tape has indeed been suggested in the past, but a more elegant solution involves a trip to your local mega-hardware store for some rubber bushings (there are bound to be some in just the right size).

Ahhh, perhaps some O-rings...

Or rubber bands.
The mount barely is big enough for my old Sony mic, but I managed to squeeze it down OK.

a little gaff tape works fine

I use a wrap or two of softish foam....maybe helps with isolation a bit more than gaffer tape would. Using a Audio Technica 4051a with the mount.

Don,,

Please take a look at my mic mount. It will allow you to use a rubber band shock mount AND mount a radio receiver, in addition to solving the too small a mic problem. Check it out at www.thej-rod.com

Happy shooting !