In 1949, the Delaware Army Guard was authorized to expand to brigade strength. Units consisted of the 261st Anti-Aircraft Artillery Brigade, the 160th Anti-Aircraft Artillery Group, the 156th expanded from the 736th and a new 945th (later the 280th) was a reorganization of the pre-war 261st Coast Artillery. The former 945th in Kent County (the old second battalion of the 198th Coast Artillery) was redesignated the 193rd Anti-Aircraft Artillery Battalion.
The reorganization was hardly underway when in June 1950 North Korea moved south across the 38th Parallel and the United States was at war again - though "police action" was the favored term. The 736th Anti-Aircraft Artillery Battalion was at summer camp when word came of its order into federal service, along with several other small detachments. About one-third of the Army National Guard, both in Delaware and nationwide, went on active duty.
The 736th served first at Fort Stewart, Georgia, then moved to Fort Meade, Maryland, where with its 90mm guns, it became one of the first units in the newly-established Air Defense of Baltimore and Washington. By the time the unit was returned to the State in 1952, few of its original members were still with it. Most had been transferred out and many saw combat service in Korea with other units under the policy of individual replacement then in effect.
Throughout the Cold War much reorganization, expansion and consolidation occurred in Guard units, especially in Delaware. Initially, two new anti-aircraft battalions, the 197th in Smyrna and the 945th in Laurel, were formed in the mid 1950s to meet these new challenges. In addition, two of Delaware's six battalions received the new self-propelled twin-40mm "Dusters," and two other battalions received the 75mm "Skysweeper" guns. At this time the 116th Mobile Army Surgical Hospital was organized in Wilmington.
90 mm M1A1
Type Anti-Aircraft gun Place of origin United States Service history In service 1940 - Used by United States Canada Wars Second World War Specifications Weight 8.618 metric tons Barrel length 53 calibers Shell 90×600 mm. R Caliber 90 mm. Carriage mobile Rate of fire 20 rpm Muzzle velocity 823 m/s Effective range Maximum horizontal 17,823 m Maximum slant Ceiling 10,380 m
The American 90 mm family of guns served as primary heavy anti-aircraft and anti-tank guns, playing a role similar to the renowned German 88 mm gun. They were the US's primary anti- aircraft guns from just prior to the opening of World War II into the 1950s when most AAA was replaced by missile systems. As a tank gun, it was the weapon featured on the 90mm Gun Motor Carriage M36 and Heavy Tank M26 Pershing, as well as a number of post-war tanks.
Prior to World War II, the primary US anti-aircraft gun was the 3-inch M1918 gun (76.2 mm L/50), a widely-used caliber for this class of weapon. Similar weapons were in British, Soviet and other arsenals. There had been several upgrades to the weapon over its history, including the experimental T8 and T9 versions developed in the early 1930s that were intended to enter service later in the decade.
However the Army became interested in a much more capable weapon instead, and on June 9, 1938 they issued a development contract calling for two new guns, one of 90 mm which they felt was the largest possible size that was still capable of being manually loaded at high elevations, and another, using assisted loading, of 120 mm caliber. The new design seemed so much better than developments of the older 3-inch that work on the 3-inch T9 was canceled in 1938 just as it became production-ready. By 1940 the second development of the 90 mm design, the T2, was standardized as the 90 mm M1, while its larger cousin became the 120 mm M1 gun.
A few hundred M1's were completed when several improvements were added to produce the 90 mm M1A1, which entered production in late 1940 and was accepted as the standard on May 22, 1941. The M1A1 included an improved mount and spring-rammer on the breach with the result that firing rates went up to 20 rounds per minute. Several thousand were available when the US entered the war, and the M1A1 was their standard AA gun for the rest of the war. Production rates continued to improve, topping out in the low thousands per month.
Like the German 88, and the British QF 3.7 inch AA gun, the M1A1 found itself facing tanks in combat, but unlike the others it could not be depressed to fire against them. On September 11, 1942 the Army issued specifications for a new mount to allow it to be used in this role, which resulted in the 90 mm M2, introducing yet another new mount that could be depressed to 10 degrees below horizontal and featured a new electrically-assisted rammer. It became the standard weapon from May 13, 1943.
In AA use the guns were normally operated in groups of four, directed by the M7 or M9 Director or Kerrison Predictors. Radar direction was common, starting with the SCR-268 in 1941, which was not accurate enough to directly lay the guns, but provided accurate ranging throughout the engagement. For night-time use, a searchlight was slaved to the radar with a beam width set so that the target would be somewhere in the beam when it was turned on, at which point the engagement continued as in the day. In 1944 the system was dramatically upgraded with the addition of the SCR-584 microwave radar, which was accurate to about 0.06 degrees (1 mil) and provided automatic tracking as well. With the SCR-584, direction and range information was sent directly to the Bell Labs M3 Gun Data Computer, and M9 Director, which could direct and lay the guns automatically. All the operators had to do was load the guns. With the SCR-584 the 90 mm became arguably the best anti-aircraft weapon of the war.
The M3 was also adapted as a main gun for various armored vehicles, starting with the experimental T7 which was accepted as the 90 mm M3. The test firing of the M3 took place on an 3in Gun Motor Carriage M10 in early 1943. The gun was used on the 90mm Gun Motor Carriage M36, and the Heavy Tank M26 Pershing.
A number of experimental versions were developed on the basic M3 pattern, including the T14 which included a standard muzzle brake, the T15 series with an improved muzzle velocity of about 975 meters per second, the even higher velocity T18, the T19 which was an attempt to reduce barrel wear, the T21 intended for wheeled vehicles, and the T22, which used the breech from the standard 105 mm M2 howitzer to take larger charge cartridges. None of these versions entered service.
In the post-war era development of the T15 continued as the T54, which included the ability to fire tungsten-cored shells at much higher velocities. The T54 was the main armament of the M47 and M48 Patton tanks, and the M56 Scorpion anti-tank vehicle.
M1 Towed anti-aircraft gun. Approved for service in 1940. Fixed on M3 mount for Coast Artillery M1A1 Towed anti-aircraft gun. Production began in 1940. Featured the M8A1 spring rammer. Rate of fire 20 rounds per minute. M2 A complete redesign to make the gun dual role, functioning as an anti-tank gun as well as an anti- aircraft gun. The ammunition feed was upgraded and an automatic fuze setter/rammer the M20 was added. This enabled the rate of fire to reach up to 24 rounds per minute. Elevation was improved with the gun able to depress to −10 degrees. To protect the crew a large metal shield was added. The M2 was the standard weapon by May 13, 1943. From the march it could fire from its wheels in 3 minutes, and from a fully emplaced position in 7 minutes. In 1944 the weapon was enhanced with the addition of proximity fused shells. M3 An anti-tank version of the gun. It was used to equip the 90mm Gun Motor Carriage M36 and Heavy Tank M26 Pershing. It is also known as 90 mm L/53.
General characteristics (M1A1)
Caliber: 90 mm L/53 Total weight: 8,618 kg (18,999 lb) Barrel weight: 1,109 kg (2,445 lb) Length with the carriage: 4.73 m (15.5 ft) Length: 4.60 m (15 ft) Width: 4.16 m (13.64 ft) Height: 3.07 m (10 ft) Weight of the projectile: 10.61 kg (23.39 lb) Rate of fire: 25 rounds per minute (at most) Muzzle velocity: 823 m/s (2,700 ft/s) Range: 17,823 m (20,585 yd) Ceiling: 10,380 m (34,050 ft) (limited by 30 second fuse) Elevation : +80 to −5 degrees Traverse : 360 degrees.
one AAA at CFB Borden, Ontario, Canada one AAA at Sangudo Alberta  one AAA at Whycocomagh, Nova Scotia  three at Pre-Fair army surplus sales, at Belœil, near Montreal, Quebec, Canada one AAA at Fort Rodd Hill - Colwood, BC  one at Savannah, Georgia: National Guard Fairgrounds one at Arundel, Quebec, Canada: Legion Hall one AAA at Sault Ste Marie Ontario  one on barbette carriage at Shemya, Alaska.  one AAA at U.S. Army Ordnance Museum.  one AAA at Broadalbin, New York  one AAA at Roswell, New Mexico  one AAA at Greenville, South Carolina  one AAA at Anderson, South Carolina VFW post