Ruger 77 mk2 can be a pain due to the stepped receiver and inability to slightly vary the position of where you may wish to mount the scope rings. I have a Jack Weigand (Weig-A-Tinney) rail fitted to mine that has solved all such problems. The company does not ship direct to UK customers so you will have to order through Brownells UK. Short action rails are usually in stock, mine, long action, had to be ordered from the US, wait time about 8 weeks.