An American martial arts master, who is a top percent combat shooter (in competitions, with moving targets, etc.) trains many SWAT teams in firearms, combat readiness, tactics and just about everything related to law enforcement, told me he believes the SAS are the most accurate shooters of any special force division. He said they're guys are much more proficient than our best military special forces (SEALS, Rangers, etc.). Surprised me, but I take his opinion higher than any others.