If you want to put a scope on to your No.1 you will need a set of Purdey or Holland and Holland mounts to fit the No. I receiver. Roger Payneicon makes very good ones if you can get them.Then,depending on your scope body ,you will then have to devise some sort of scope clamping method as the scope rings were usually soldered on the original scopes. I did this ,made Purdey mounts from scratch and mounted an Aldiss scope on a SMLE. It took a great deal of work to do and I wouldn`t do it again!. To be honest,unless you have a good deal of skill and a decent workshop I would forget it!