I double up with soft earplugs and the Howard Leight muffs.
Second the motion. That's exactly what I use. If cheek weld isn't an issue I have an old set of Dillon electronics that are a little deeper and seal very well.
One thing that did help was switching hats from a ballcap to a fatigue hat - the headpiece on the phones was pushing the button on the latter directly down into my head and after a while it hurt.