Royal Marines with 42 Commando are supported by Viking APCs during a simulated attack during Exercise Black Alligator 2015, California.
This image gives a good idea of the amount of firepower the Royal Marines can bring to bear. There are dismounted heavy machine gun teams operating tripod-mounted L1A1 HMGs, machine gun teams firing L7A2 GPMGs in sustained fire (SF) mode. A anti-tank teams, armed with Javelin missiles, can also be seen.
42 Commando is currently (October 2015) in its force generation cycle. The training in the US is preparing 42 Commando to take on the role of high-readiness Lead Commando Group (LGC) in the spring of 2016. In that role, they will become the core fighting element of the Response Force Task Group (RFTG) and will be on alert to deploy on contingency operations on a worldwide basis.
US DoD photo By: Cpl. Demetrius Morgan