I have a summer 2012 Gen4 G19 that was problematic with BTF. Tried all the factory recommended fixes with no luck. Switched to an Apex extractor and it ran better for a couple thousand rounds, but recently started with wonky ejection again. Put the HRED in with the factory extractor and now it's throwing brass cleanly and forcefully again. Time will tell if this fix "sticks" or if there's something to do with age/round count that causes "problem" G19s to gradually worsen over time...