During the interwar years the U.S. Army organized its infantry regiments with "howitzer companies," armed, with among other heavy infantry weapons for want of actual infantry support howitzers, 37 mm M1916 guns. The Regular Army could not afford to maintain full companies (instead using platoons), but the National Guard could. The Army adopted a .22 caliber sub-caliber device as an economic measure that allowed training with the guns on indoor ranges. By 1941, the howitzer companies of regiments were disbanded and converted to antitank platoons; the Army put most of the M1916 guns into storage, scrapped them, or converted their mechanisms for use as sub-caliber training devices for heavy guns. Some were used in the Philippines campaign in 1941-42 as antitank weapons due to shortages of the 37 mm gun M3. The Japanese Type 11 37 mm infantry gun was based on this design.