Don’t press the minor spherical button under the ejection port while you’re putting a cartridge into the chamber, it can hurt! (Photo courtesy icollector.com). Created in 1898 John Moses Browning’s Auto 5 was in creation by different suppliers from 1902 up till 1998. The earlier guns made by Fabrique Nationale https://autoordnance-thompson98528.ampedpages.com/detailed-notes-on-where-to-buy-the-hk416-61634485