My first time using the BCM comp I took one shot without ear pro and found out it is very loud.
I switched uppers, both the uppers are 16"- the Comp'd one is a Mid-length though, and fired one shot without ear pro with the A2, and I could tolerate it just fine.
Side blast with the BCM comp for me, while a friend was shooting, was not bad.
So, the BCM comp is louder than the A2. It helps the rifle shoot much softer though.

