I have a new five-seven the first 3 mags fired flawlessly. After that the gun fires a cartridge but fails to eject or feed and leaves the fired Brass case in the breech but does set the hammer so the next time you pull the trigger the hammer comes down on a fired case. If you cycle manual it ejects and feeds another round.
Anyone out there got any ideas before I contact FN to get an RMA number.
The firearm is under warranty. I'd suggest you take advantage of the free repair under warranty. If you just attempt to repair it yourself you may (probably) will void the warranty. Having said that did you clean & oil the firearm before shooting it?