A training magazine and safety system for a magazine-fed firearm are provided. The training magazine includes a safety block at a top of the magazine, configured to block the breach of the firearm and thus keep the bolt of the firearm locked to the rear such that the firearm is incapable of firing. The safety block can include a notch in a front portion thereof, which is configured to accommodate a chamber flag while the chamber flag is in the chamber of a firearm. As such, the chamber flag and training magazine can be used together as a safety system. Methods of training are also provided.