If folks want the accuracy achieved by folks in matches winning and record setting in both shoulder fired and free recoil disciplines, they will not have any synthetic bedding touch the barrel underneath its chamber or any place else.
Under-chamber bedding's a sure way to cause vertical shot stringing. If one doesn't see this happening, they have other accuracy issues that mask it.
US Navy Distinguished Marksman Badge 153
Former US Navy & Palma Rifle Team Member
NRA High Power Master & Long Range High Master
NRA Smallbore Prone Master