If I read this correctly you have a carbine buffer in a rifle buffer tube with an AR-15 buffer spring. No good.
The AR-15 Spring is to light for the AR-10 which could cause harsher recoil and cycling issues. The buffer is to short for the rifle buffer tube. They have the little bumpers on them because they can/will bottom out in the tube which keeps them from traveling to far. With a shorter buffer and lighter spring the carrier could over travel.
Replace with a .308 rifle buffer and .308 buffer spring.
This be true, if ar15 spring/tube/buffer used it will not cycle right, will have chambering problems.