If you're thinking of doing this because a 3" shell seems to fit a 2 3/4 chamber, it's because chambers are sized for the fired shell, not just the unfired ones.
It's to make room for the extra case length when the crimp opens.
Where's the extra length of the 3" shell going to go when it's fired in a shorter chamber?
Walt Kelly, alias Pogo, sez:
“Don't take life so serious, son, it ain't nohow permanent.”