dont let it shatter your confidence , it happens to everyone . i did it too but didnt drill it out , just saw the thread and fitted a "pot" muffler . just a little CRC and screw it in slowoly , cleans the treads as it goes in , same a tapping . slow and lube , out and more lube . they look ok too and most had an option of b
oth so really no biggy .
as joe said , just throw a different muffler on , as long as you didnt drill too deep ...
,Dave
ps , next time , file it flat , centre pop it and drill straight that way the drill bit wont move of centre take it slow and easy always
