Medium regiments were organised into 2 gun batteries each of 2 Troops of 4 guns each. Guns were either 6 inch 26 cwt Howitzers or 60 pdr Guns. This table is based on a 6 inch regiment, establishments were slightly different for 60 pdr regiments. There are also slight differences between units using Medium Dragons and those using Heavy Tractors to tow the pieces.
With the introduction of the 4.5 inch Gun in 1941, followed by the 5.5 inch a little later, the older guns were phased out, although the 6 inch remained in service in the Far East until the end of the war. The regiment was organised into 2 gun batteries each of 2 Troops of 4 guns each. At first, regiments would usually have a battery each of 4.5 and 5.5 inch Guns. The 4.5 inch was not popular because although it had a greater range it did not have sufficient weight of shell compared to the 5.5 for its role. Towards the end of the war, most regiments had both batteries with 5.5 inch Guns.
The following organisation is for both batteries equipped with the 5.5 inch Gun. Regiments having one battery of each equipment would have 4 less 3 ton trucks and drivers and 22 less gunners for ammunition handling.