Sierra Polymer Cased Ammo

[FLshooter]

Never heard of the Sierra poly ammo.But,I have read posts about polymer cases and injection molded bullets.I think the military considering poly ammo because of the weight reduction over brass. I guess they would be good for hunting. But not good reloading because the case neck gets chewed up by the ejector.
Anyway I can’t remember where I read it. But I have seen this video on YouTube about polymer cases ammo.

https://youtu.be/mCjNkbxHkEE