Follow-up to my posts above. Sordin continues to be unresponsive about my warranty claim. This morning I found email addresses for their CEO and Site Manager. So I complained to them asking for a replacement battery compartment or new muffs. That will probably continue to result in crickets, but maybe I'll be pleasantly surprised. I'm not holding my breath.
Anticipating the cricket serenade from Sordin, I contacted SRS Tactical. I talked with a very pleasant and helpful man named Patrick. SRS Tactical can service the muffs. They will also sell me a replacement battery compartment. From a career of electrical engineering, I know my way around circuit boards and soldering irons. So, for around $20 plus shipping, I'll have the replacement part. Unless I'm way off base, that should fix my headaches. It's worth a shot, and a lot cheaper than shipping the muffs to Sweden (if I even have that option).
If the new battery compartment doesn't do the trick, I'll just move forward and install a rechargeable coin cell battery and charger. That's not a technical problem, but it will take a fair amount of fiddling around. I think it would be great to have rechargeable Sordin muffs. I do like the muffs, it's just that they're unreliable as they are now.