I have a 2A Arms slick side upper on my Grendel, and I believe Aero Precision makes one as well. Probably others available.
Edit to add: I have a 5.56 blaster rifle with a high round count. I have gotten it so filthy that rounds didn't want to go into the chamber, but only maybe once did I manage to pound a round in with the forward assist and get it to fire. I have had a lot better luck aggressively cycling the action when it gets sticky. .
Edit to add: I have a 5.56 blaster rifle with a high round count. I have gotten it so filthy that rounds didn't want to go into the chamber, but only maybe once did I manage to pound a round in with the forward assist and get it to fire. I have had a lot better luck aggressively cycling the action when it gets sticky. .