This is a 155 millimeter M1A1 heavy field gun on carriage M1, developed by the United States Army during World War Two. The gun was nicknamed “Long Tom” because of it’s almost 7meters (22ft) long barrel and was deployed as a heavy field weapon or as secondary armament for seacoast defense. It could fire a 45kg (100 lb) shell over a maximum range of 23km (14 mi), with an estimated accuracy life of 1,500 rounds. The gun was produced from 1938 to 1945.
My dad was a SSgt on an artillery unit employing one of the “LONG TOMS” in WWII. Too bad we didn’t have the internet sooner! Being older than many when he was drafted, he served in a training role before and early in the war but was in two major campaigns as the war neared its end.