I have no reliable information regarding whether or not the Mannlicher Carano rifle alleged to have been used to fire at the President in Dealey Plaza was fired or not on the day of the assassination.
However, I am testing a hypothesis, that we have proof Oswald did not fire a gun that day. The proof has two parts. One part is indirect, but important. The indirect part of the proof is that there is no reason to think Oswald fired a gun that day. The other part of the proof is the parrafin tests showed only signs of powder residue consistent with handling boxes,. No powder found on his face, which proves he did not fire that bolt action rifle from the window.
As for the gun itself, I don't know for sure the Mannlicher Carcano was used or not used in the shooting