The 16-inch HARP gun at Barbados held the record for the largest gun in the world with a barrel length of 119 ft and weighing 200 tons. It consisted of two 16-inch U.S. Navy gun barrels welded together and smooth-bored to 16.4-inch diameter. It was capable of firing at a muzzle velocity of 2,164 m/s (7,100 ft/s) with a maximum acceleration at launch of 15,000 g. It launched an 181-kg shot with an 84-kg payload that could reach an altitude of 181 km (595,000 ft). For propellants, the 16-inch gun used either the solvent type WM/M.225 or the solventless M8M.225, both of which were manufactured by Canadian Arsenals Limited. During testing, a camera station set up on the islands of Barbados, Saint Vincent, and Grenada were used to photograph the trimethylaluminium trails released from the projectile during launch, which provided data on upper atmosphere wind velocities for different altitudes.