I have been running A53M mounts for many years with my 460s with no issues. Snug fit, particularly in summertime. To avoid this, I simply swipe a little talc on my fingertip a couple of times a year and swab the inside of the rubber ring just a tad, and the 460 bodies slide in and out just fine. I actually like the snug fit because I know the mics are secure when mounted.
A couple of clarifications on some statements from earlier posts.
The ring is hollow and filled with air, not powder. It is basically like an inner tube, and just like an inner tube, has some talc inside but air is what inflates them. Also, they can deflate permanently if mishandled, and I don't believe they can be modified without risk of deflating the shock ring.
If you look at photos of GD shows from the late '80s and early '90s, you can see Bob, Jerry, and Phil singing into Milab mics with either Milab shocks or the A53Ms shocks. That is how I first found out about these Shure mounts.