Need help with not cycling

[leopard6.5]

DIESEL758: It might be just my experience but I've never had a charging handle pull back as hard as you are describing even when brand new.

Mine have always been like what you described with your .223, sometimes maybe just a little harder when new but nowhere near as hard as you're saying your Grendel is.

Are you seeing any scratch marks inside the upper receiver or metal shavings inside the upper receiver?

Good luck and let us know what you find.

Lee