The Canadian Diemaco C8 Rifle has been approved for use for the Royal Marine 43 Commando Fleet Protection Group. This unit, part of 3 Commando Brigade and is based at HMNB Clyde, Faslane, Scotland, has one of its important tasks of protecting the Trident nuclear programme.

The Diemaco C8 Rifle is not exactly a new rifle in use in the British Armed Forces, since it is already in use in special forces units and replacing the M16, the news marks the first regular British armed forces unit to use a rifle other than L85A2/SA80 bullpup rifle. The Diemaco C8 Rifle is designated as the L119 in the British Armed Forces.

According to Janes, the roll out of the weapon to the 790-strong commando group has been completed by the end of 2015. Also, in July 2013 the Ministry of Defence contracted Colt Canada for a £2.8 million upgrade for the L119A1 giving it a designation of L119A2.

The unit has been equipped with the Heckler & Koch MP5 submachine guns and has already been using the L119 in limited use, but with the news, the L119 will be the primary weapon. It uses the standard 5.56x45mm round and was chosen as it has "reduced ricochet, limited collateral damage" features. The other protection unit that uses the rifle is the Royal Military Police Close Protection Unit.

The 43 Commando, apart from fleet protection, is also tasked to in deploying recapture tactics teams and ship boarding specialist teams. This means that the unit usually operates in close quarters environment, thus needing a low velocity rounds and the L119 can handle such rounds better than the SA80.

For airsoft players wanting to use an airsoft Diemaco C8, they will need to make a custom build one using any available airsoft M4s in the market and they will mainly need to change the receiver by using the G&P Canada C8 Metal Body. There is also a complete custom G&P C8 AEG that can be purchases from eHobby Asia for US$278.00.