M4A1 gen8 Not firing correctly

Hi all, I have a gen8 M4A1. It’s currently only firing gel balls about 5-10m atm. I have ruled the balls out as my AR-15 shots them fine. I am using a double barrel as the clip and once again once loaded into the AR-15 they fire with ease.

I have place my hand at the end of the barrel and i can feel quite a lot of compression out of the barrel so I’m wondering if it’s a feeding issue? Any thoughts :thought_balloon: