3 popular rimfire and red dot

i think only the Buckmark.

The Ruger shouldnt need to remove the rail, and im not too sure about the 41.

On the Buckmark it depends upon which model pistol and which model red dot sight. On the models with the rail that runs the full length of the barrel you can leave the red dot installed and simply remove the rear screw and the front barrel screw and leave it attached with the barrel. With a basic model that you've simply replaced the top strap of the pistol with a rail it will depend upon the length of the red dot as to if you can access the attachment screws without removing it from the base but it is removed from the barrel and frame.