The Ordnance BL 6 inch 26cwt howitzer was a British howitzer used during World War I and World War II.
The Ordnance BL 6 inch 30cwt howitzer was a British medium howitzer used in the Second Boer War and early in World War I. The qualifier "30cwt" refers to the weight of the barrel and breech together which weighed 30 hundredweight (cwt): 30 x 112 lb.
The gauge of a firearm is a unit of measurement used to express the inner diameter (bore diameter) of the barrel.
A howitzer is a type of artillery piece characterized by a relatively short barrel and the use of comparatively small propellant charges to propel projectiles over relatively high trajectories, with a steep angle of descent.
The 6 inch Howitzer, Model of 1908 was the standard American heavy howitzer before World War I. Forty-two of these weapons had been produced before 1917 and all were employed for training stateside in that war.