Considered by many to be the best field cannon of the war, the 25-pdr had a round plate that would be set under the wheels in order to provide a smooth surface which alowed the crew to turn the gun to face new targets.
My LEGO version has a rotating plate, and the gun can elevate up to about 45*
When being transported the round plate would be attached under the legs. The gun would then be hooked to a special trailer which carried ammunition, and that trailer would then be hooked up to a vehicle. one of my next projects will be the trailer, and editing the universal carrier to hook to it.