Has this happened to anyone else?
I have run about 2K rounds thru this so far, with not one jam. I field stripped my trusty reliable and very fun Colt (Umerex) Tactical .22 M16, upon breaking it open a part fell out. I was shocked, then realized it was the rear “plastic” bumper P/N 576.20.09.1. I have no clue why they used plastic and not aluminum of another softer metallic part. New bumper is pictured with the broken bumper.

Plastic bumper P/N 576.20.09.1 part is referenced here as #63 from the manual.

This was still under warranty, I phoned Umerex, and they sent me out another bumper no charge. Great service.
I use High Velocity .22 ammo; however, I have not adjusted the bolt speed from the stock setting. It works great as is, but do you think this contributed to the demise of the bumper?