Complex sentence: There is some discussion over whether the cooling tube was effective or even necessary--in the Second World War many old aircraft guns which did not have the tubing, were issued to anti-aircraft units of the British Home Guard and to British airfields.
Split into simpler sentences: There is some discussion over whether the cooling tube was effective or even necessary--in the Second World War. Many old aircraft guns which did not have the tubing, were issued to anti-aircraft units of the British Home Guard and to British airfields.