I just did an inspection of my muffler and found that it was basically coming apart inside.  This is a Burns Stainless, 17" 2-Stage muffler after 50 hours of flying behind a 2-rotor engine.  Now, it could be that 50 hours is a reasonable life for something like this, I don't know.  But, it certainly confirms the stories of muffler disintegration.  I've inspected this muffler several times over the last 50 hours, but this is the first time that I've seen damage.  But, when it comes apart, it really comes apart.  It is unfortunate, as the muffler was really effective in reducing the noise and was light-weight.

Best Regards,

Steve Thomas

Thanks for the heads up Steve. My contention is put nothing inside
unless it is a cooling tube with fresh air flowing through it.
Here are a few alternatives.

You might make the best of it and send it back to Burns.
They might do a little free R&D to save face.

Paul Lamar