On the same day I received these covers, I had to send my new upper back because it wouldn't cycle the bolt when fired, so I haven't had a chance to use them. I'm not worried about the quality or the service these covers will provide however. Having spent 27 years in the Army, I learned a long time ago that you should always trust your NCO's. I have a neighbor who's a SSGT in the 75th Ranger Regiment who says these are the covers he uses on his Combat Rifle, so I'm going to go with him. If he say's they're OK, then for me they'll be OK, and I suspect for anyone reading this, they'll be OK. Based on this, I'd recommend them to anyone reading this.