Welcome from SW Florida, USA! Glad you found us but as James6591 pointed out you woud get better feedback over on the "Ruger Pistols" forum. This "Feedback" is aimed at using the website in general.
But to answer your question anyway, no, you cannot fire with the magazine disconnected due to the magazine disconnect mechanism. There is also an advisory in the owner's manual about dry firing with the magazine disconnected - don't do it.
Wave