The NRA, or the National Rifle Association, is a gun rights advocacy group based in the United States. Founded in 1871, the group has informed its members about firearm-related legislation since 1934, and it has directly lobbied for and against firearms legislation since 1975.
He is referring to the bombing of Britain by Hitler's forces (also known as the Nazis). He was also said to have stated about this "It is not the size of the dog in the fight; but the size of the fight in the dog."