How do I remove muffler on 372xp?

[mredden]

I need to inspect the piston which I suspect I damaged on New Year's Day. I have removed the two Allen bolts on the little bracket on the front of the muffler AND the two longer allen bolts that go into the muffler housing. Pulled and pried. It won't move. I see nothing else except a small screw in the top of the muffler housing that won't budge and that my untried eye interprets as holding two sections of the muffler housing together - If I drill that out, will that allow me to separate two sections of muffler to get to other bolts inside the muffler - or is there something else that I am missing?

Back story. Cut and bucked very large Live Oak limb that was covered in ferns over a layer of old, dead fern that had turned into dirt. Had to stop and sharpen very frequently. When I was down to three (large) cuts at the @22" base, I sharpened for what I thought would be the last time that day. First cut, okay. Second cut lugging some and throwing sparks in that very hard wood. Third and final cut: sparking and chain smoking, barely cutting. I impatiently pressed on (Yeah, I'm a dumbass) My saw just kind  of petered out. Cooled it and checked bar and chain. Okay. Gassed up the saw, but it never re-started. Drop test was a good glug-glug-glug. New spark plug - no effect.

Not optimistic and not mechanically gifted/knowledgeable though I have quite a few tools in my wood shop.

[Grandpa]

There are two holes in the front of the muffler, there are bolts in the bottom of those holes.