Хм, искал по поиску L119 и что-то меня терзают смутные сомнения, о том ли вы?))

L119
A version of the Light Gun, known as the L119, has a different barrel (the slightly shorter L20 ordnance with a percussion firing mechanism) for firing the widely used US M1 type ammunition (UK 105 mm How). In British service this was only used for training at the Royal School of Artillery while stocks of 105 mm How ammunition lasted. Britain disposed of its last L119s in 2005. However, it is popular with many export customers who still rely on M1 ammunition.

По моему это 105 мм пушка...