The following letters correspond to the months of the year Month Codes: This is an old British measurement system. Scope bases designed for Model 700 long action rifles should interchange with the Model 721. If you install swivel studs on a synthetic stock, you will void your warranty on the stock. 244 Rem.? The nominal suggested range of charge weight produces the best combination of accuracy and velocity. Do you have information on a Model 760 Gamemaster? and the. Using different combinations of bullet weights, bullet types, and propellant types will result in a variation of bullet velocities, accuracy and felt recoil, even in pistols of the same model.