Precision stamped, stainless steel magazine box has .110" additional length to provide the required clearance for extra long rounds. Extended box has plenty of room for the popular .300 and .338 Ultra Mag and other calibers based on the .404 Jeffery case. Extra-long feed lips give reliable feeding with .284 Win. cases. M-70 fits Winchester Model 70; increases magazine length from 3.4" to 3.82". Requires machining receiver and altering bolt stop and ejector. Mfg: Wyatts Outdoor SPECS: Stainless steel. Capacity: Extended - 3.91" (9.62cm) long. M-70 3.82" (9.7cm) long, fits Winchester Model 70 long action. Capacity three rounds.