The six-inch howitzer would be 15 centimetres, the four-inch would be about 10 centimetres. In 1934, the guns were displayed at the Vancouver Exhibition, the precursor to the PNE. But a 1940 story ...

“Based on the photograph I’ve seen, I think it’s a 15-centimetre field howitzer ... “They consisted of one six-inch howitzer, one four-inch field howitzer, two three-inch field guns ...