The older Rugers do not come with a mounting system, now they do because of this reason. You will probably need to get the specialized rings from Leupold. Brace yourself, they are a little spendy. Plan on spending about $75 depending on the scope model and scope barrel diameter. Question a gunsmith for the rings you need for the scope you have and then shop around. If you are lucky, you may be able to pick up a set used. Good luck!