You mean registered as a machine gun? Before 1986 when the Federal government closed the machine gun registry? It is better that people think you to be a fool than to open your mouth and remove all doubt.
You see, your Titan .25 became a machinegun the first time it fired more than 1 round with a single action of the trigger:
26 U.S. Code § 5845 - Definitions | LII / Legal Information Institute
"(b) Machinegun
The term “machinegun” means any weapon which shoots, is designed to shoot, or can be readily restored to shoot,
automatically more than one shot, without manual reloading, by a single function of the trigger."
Therefore, the first time your Titan fired more than 1 round by a single function of the trigger in your presence you knowingly came into possession of an unregistered machinegun in violation of the National Firearms Act of 1934.
David Olofson got 30 months in the slammer when he transferred his "unregistered machinegun", an AR-15 that also malfunctioned and fired more than 1 round with a single action of the trigger:
Prison term for ?broken gun? case ends