Welcome aboard
Gill/Clackety-clack gun, nifty gems. Look cool, and have a unique action. The bolt doesn't close until the trigger is released, but fires from closed bolt (hence the clackety-clack sound). The charging handle can be pressed into the receiver for firing so it becomes a straight pull bolt action, and allow the use of all manner of .22 ammo. Only semi (self loading) with .22lr.
The few I've owned/fired were quite accurate. I've also encountered troubled gems, and they can be tricky little cusses too.