From what I can remember of the few M65 mags I've had, they were all metal, including the follower. The "Magnum" magazines were interchangeable from 7mm, 300 WM and 338. The Standard length (270/30-06) mag would fit the magnum, but the followers were different. This is the same case with the Parker Hale, mag length is the same but followers are different between the intermediate, standard and magnum.