I see a crossbolt going through a receiver. This is a no no in my book. You could be pinching the receiver or distorting it in a way that is causing retardation of the carrier's movement. I am not sure this is the problem, but when someone has an issue with a gun as proven as the M1014, and it's not in factory configuration, I opt to return it to such, operationally, before further diagnosis.
Further, the mag tube/spring comment above is very on point, as well.