Hi. Mate your probably better off getting a steel or aluminium breech with scope rails machined in, far better than bolt on plastic mounts that you have to fit with standard breech. Try GMAC not cheap but defo do the job if your ok at stripping your ratty. Put new seals in whilst stripped. Warning you can spend a small fortune (I have) blinging ratty's, mines currently putting out 10-12lb ft running on 3000 psi paintball tank running at 800psi output (250 shots per fill).