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M1917A1 Caliber .30 Heavy Machine Gun and TM9-1205 Manual

Fully automatic, recoil operated, water-cooled, Caliber .30 (7.62mm), 174 gr bullet, 50 gr charge, 2800 fps muzzle velocity, 400-600 rounds per minute rate of fire and a 1000 meter effective range, the M1917A1 was a deadly defensive weapon. Too heavy for continuous action in fluid combat situations, the Weapons Platoon would typically move at least one HMG to each forward platoon at night for defensive actions, and for use in support action for the next morning's maneuver action.

USMC: Machine Guns, 1951

Maintenance Manual All Types Browning .30 Machine Gun

M2 .50 Cal MG Photos, specs, links

WWII Small Arms Technical Manual

M1917A1 .30-caliber Water-Cooled Machine Gun

M1917A1 .30 Caliber Water-Cooled Machine Gun
34th Infantry, At the Ansong
Comparison of Browning MG Series
Operation Fully automatic, recoil operated, water-cooled
Caliber .30 (7.62mm)
Ammunition Ball M1; 174 gr bullet, 50 gr charge
Muzzle velocity 853.4 mps (2800 fps)
Capacity 250-round belt
Weight 93 lbs, approx, with tripod and water
Overall length 38.5 in
Rate of fire 400 to 600 rounds per minute
Effective range 1000m (1100 yds)

The M1917A1 was designated as a Heavy Machine Gun for a very good reason: it was heavy! It was not a weapon easily used in fluid combat or assault. However, the weight of this water-cooled weapon also gave it great stability which, with its capability of sustained volume of fire, made it an excellent defensive weapon.

The heavy was also very reliable. The anti-freeze in its coolant made it dependable even in the intense cold, as in the Chosin Reservoir battles. For stopping massed, or wide-spread infantry assault, the .30 heavy was one of the most effective weapons the infantry had during the Korean war.

The Chinese also used water cooled heavy MGs with effect. Firing their eerie green tracers at night to mark targets for their infantry, and soften up the targets themselves, the old-fashioned, wheeled Chinese MGs, with their metal shield for the gunners, was an ideal support. Doubtless also using anti-freeze, the Chinese water-cooled MGs were probably their most effective weapon during the first year of the Korean war. I won't qualify this with the term 'infantry weapon', because the Chinese army was all infantry, at least during the first few months of their crushing entry into the Korean war.

American forces used the light and heavy machine guns mostly at a few hundred yards or less, contrary to their design concepts. This was the nature of the battles our company and platoon sized forces faced. The Chinese used them at greater distances but, at least in the early phases of the Korean war, used them sparingly at these distances. Probably because of the difficulty of transporting ammunition over long distances on foot, which was often their only available method.

The North Korean armies, on the other hand, were well supplied with the Maxim heavy machine guns by the USSR, and used them in large quantities in the Pusan Perimeter battles. The NK, well trained and largely veterans of China's civil war, would site these weapons at long distances to place grazing fire on slopes we were attacking. Beyond hearing range, using smokeless powder, sighted in with great professional accuracy, the first inkling our troops would have that they were under aimed fire would be when their comrades' bodies and faces were suddenly torn and shattered.

The functional mechanisms of all these machine guns are relatively identical
Parameter M1917A1 M1919A4 M1919A6
Mount Tripod, 53.2lb Tripod, 14.3lb Bibod, attached
Weight of gun with water 41.00 Ib  
Weight of gun w/o water 32.6 Ib 30.5 lb 32.5 lb
Length (over-all) 38.64 in. 37.94 in. 53 in.
Weight of recoiling parts 7.35 Ib 11.7 lb (approx) 7.5 lb
Weight of barrel 3 lb 7.35 lb 4.65 lb
Length of barrel 23.9 in. 24 in. 24 in.
Length of rifling 21.38 in. (71 cal.)
Bore Cross-sectional area 0.0740 sq in.
Type of mechanism Short recoil
Feeding device Fabric belt Link and belt
Capacity of feeding device 100-250 rounds
Rate of fire rounds/min 450-600 400-550 400-500
Cooling system Water (8pt) Air Air
Sight radius ??? 13.9 in. 13.9 in.
Sear release 9 lb
Trigger pull 7 lh (min); 12 Ib (max) 8.5 lb
Ammunition types Ball; AP; tracer
Comment courtesy of R. E. Sullivan, Colonel, USMC ('43/'67) (Ret.)

You mentioned anti freeze at the reservoir. We didn't have any to my knowledge.

So the evap can and jacket had to be drained if it didn't look like you were going to get a target for awhile. The crews at times had to line up and urinate in the jacket in order to get liquid to keep the gun cool. (Packing the jacket with snow wouldn't work since snow yields one part water to 10 of snow).

One more point about the HMG. Each rifle company machine gun platoon was equipped with 6 HMG and 6 LMG. When we possibly could do it the HMGs would be brought forward when you went into your night defensive positions, and supported the attack by fire the following morning prior to being packed up to move forward again. The LMGs went with the assault. So on a battalion front you'd have 18 heavys and 18 lights.

A formidable force indeed. In front of Seoul 2/5 from the 104 fights without a single heavy gun in action. We'd run into a swarm of 45mm AT guns, and they had sniped our heavy guns out of existence. Those 45mm AT guns fired a round that you could see leave the barrel and proceeded along like a red hot baseball. You could see them coming if they weren't aimed straight at you. Chilling.

45mm Anti Tank NK artillery

At the end of 1931, Soviet designers installed a new 45mm barrel on the gun-carriage of the 37mm Anti-tank Gun Model 1930 and slightly strengthened it. The new gun was accepted for service in March 1932, under the designation of "45-mm Anti-tank Gun Model 1932"; the gun's factory designation was - "19K" Field Gun.

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