The magazine follower, which pushes the cartridges into the feed port, is equipped with rollers to reduce friction and the firing pin is designed so that it does not line up with the primer in the cartridge until the cartridge has entered the chamber.
The magazine follower is equipped with rollers. This was to reduce friction. The magazine follower pushes the cartridges into the feed port. So that it does not line up with the primer in the cartridge until the cartridge has entered the chamber. This was what the firing pin is designed.