Thought I'd noticed this a while back. After reading this, figured I'd do a little experiment while my beer chills.
Using my stick software, set the secondary fire button to a single nonrepeating keypress of .01 seconds in length. Used the target 100 command, rolled out of the hangar, and stopped. Using just the secondary button I'd mapped, I emptied the cannon into the target. Tried this 3 times. What I observed is that the Yak fires 1,2 or even 3 rounds (Ammo counter decrementing, hit sprites, and holes in the target as well). In contrast, the 109's fire a single round, period. Did the 9T really have an 1800rpm ROF?