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Section Leaders:
The M4A1(76)W Medium Tank By
Dan “dano6” Kowaleski Introduction: In
July 1943, the M4 series of tanks underwent a major redesign by the US
Armored Force. Production of all 75mm-armed M4 variants were cancelled
except for the M4A3. It was decided that some of the M4A3s produced
would remain armed with the 75mm M3 gun because of to its superior HE
shell performance, while the majority of the M4s produced would be
armed with the 76mm M1A1 gun. The last 75mm armed M4A1 rolled of the
assembly line in December 1943. The
new M4A1(76)W would be the first 76mm-armed M4 variant to reach
production and the troops in the field.
Development: During
1942 and early 1943 many modifications were recommended from both
combat experience and testing for the M4 line of tanks. In order for
these modifications to be standardized throughout all of the models, a
major redesign of the M4 Sherman was undertaken. It was decided that
almost all of the M4s produced would be armed with the 76mm gun in
place of the lower velocity 75mm M3 gun. A new turret would be required
in order to accommodate the 76mm gun and a new commander’s vision
block cupola would be installed in place of the older style split hatch
type. Wet storage for the ammunition would be incorporated into all new
tanks to better protect the crew from fires inside the fighting
compartment. Thicker armor for both the gun shield and the front hull
was incorporated in the new designs, along with improvements to the
engine, providing greater mobility and reliability.
The new M4A1(76)W was a better tank than any of the Mk.IV German
variants, but encounters with the formidable new German Panther tank
would once again show that the US was behind the Germans in tank
development.
Armament: The
main armament for the M4A1(76)W was the 76mm gun, referred to as the
M1A1, M1A1C or M2. The M1A1 was an earlier version of the gun that was
not threaded for a muzzle brake. The installation of a muzzle brake
greatly reduced recoil and the amount of dust kicked up by the gun by
directing the muzzle blast to the sides. The addition of a long cord
primer to the ammunition reduced the amount of smoke in the muzzle
blast, and both of these implements greatly reduced the amount of
target obscuration after the firing of the main gun. The M1A1C and the
M1A2 both were threaded for muzzle brakes, while the newer M1A2 gun
also had tighter rifling in the barrel, which resulted in greater
projectile stability and accuracy while slightly increasing armor
penetration. Fitting
the 76mm gun into the existing turret of the 75mm M4 was rejected by
the US Armored Force due to room limitations. The turret designed for
the T23 medium tank was used in its place. The gun was mounted in the
M62 gun mount with the direct telescopic sight M71D. The backup
periscope sight M4A1 was still retained. The
secondary armament for the M4A1 was two .30 caliber machineguns and one
.50 caliber machine gun. One of .30 caliber machine guns was mounted
coaxially with the main gun in the turret mount and the other .30 MG
was mounted in a rotational ball turret in the front hull. The .50
caliber machinegun was mounted on the turret roof next to the tank
commander’s hatch for anti-aircraft purposes. Armament Performance (Armor Penetration): 76mm
M1A1, M1A1C, and M1A2 gun: Muzzle
velocity APC M62 and AP M79: 2,600
fps(792.5 m/sec) Muzzle
velocity HVAP M93:
3,400 fps(1036 m/sec)
Armor
penetration at 30 degrees obliquity: APC
M61 at 500 yds.
3.7 inches(93mm)
APC
M61 at 1,000 yds.
3.5 inches(88mm) APC
M61 at 1,500 yds.
3.2 inches(82mm) AP
M79 at 500 yds.
4.3 inches(109mm) AP
M79 at 1,000 yds.
3.6 inches(92mm) AP
M79 at 1,500 yds.
3.0 inches(76mm) HVAP
M93 at 500 yds.
6.2 inches(157mm) HVAP
M93 at 1,000 yds.
5.3 inches(135mm) HVAP
M93 at 1,500 yds.
4.6 inches(116mm) The 76mm gun gave the M4A1 Sherman the ability to penetrate most of the common German tanks on the battlefield during 1944-45. The 76mm gun could easily penetrate the front armor on any of the Mk.IV variants at ranges over 1,500m and it could penetrate the Tiger I’s frontal armor at ranges up to 800m with the APC61 and AP79 ammunition. The development of the M93 APCR-T ammo gave the 76mm gun even more penetration power and the ability to destroy German tanks at even greater ranges. This ammo became available to the Tank Destroyer units in August 1944. US tankers in M4s were not supposed to be able to get the new ammo but many tank crews bargained and bartered with TD crews and ordinance supply personnel to get a few of these precious rounds. By the end of the war these rounds had become more common and almost every crew had at least a couple in case of an encounter with a heavy German tank. The
76mm gun had another advantage over the lower-velocity 75mm M3 gun. It
had a much flatter trajectory due to its higher muzzle velocity, which
increased the gunner’s chances of hitting a target at longer ranges.
The flatter the trajectory of a given projectile the closer together
the ranging lines are on the gun sight. An error made by the gunner in
range calculation and aiming is reduced because the projectile still
has a better chance of hitting the target because the arc of the
outgoing round is less. The greater the arc of the projectile the more
exact the range calculation has to be in order for the projectile to
hit the target. Even
though the 76mm gun was a much better anti-tank weapon than the 75mm M3
gun it replaced it did not have enough power to penetrate the front of
the new heavy German tanks that were seen in the ETO. These tanks were
the Tiger II and the Jagdtiger, and both had frontal armor that was
well sloped and too thick for the 76mm gun to penetrate even with the
APCR-T M93 projectile. Another new German tank that was encountered in
much greater numbers than either the Tiger II or the Jagdtiger was the
Mk.V Panther medium tank. The 76mm gun had problems penetrating the
upper-front glacis plate of the Panther even with the M93 projectile
but hits to the thinner lower front hull resulted in penetrations at
almost any range with any ammo. The front turret armor of the Panther
was thick enough to stop penetrations by the APC61 and AP79 projectiles
at ranges greater than 300-400m. Hits to the side and rear of the hull
and turret by the 76mm AP ammo resulted in penetrations at ranges over
2500m. The M93 ammo could penetrate the front turret armor of the
Panther at ranges over 1,500m and could penetrate the sides and rear of
the hull and turret at ranges over 2,500m. Penetrations of the front
glacis plate of the Panther with the M93 ammo varied greatly due to the
variation in the quality of the armor present on each Panther.
Penetrations were recorded up to 800m on some vehicles whereas
on others, the M93 projectile could only penetrate at ranges closer
than 100m and in some cases, not at all. The
new 76mm gun had one disadvantage compared to the 75mm M3 gun,
its HE shell was not as powerful. The high explosive ammunition
for the 76mm contained an explosive charge of .86 lbs. compared to the
75mm HE ammunition that contained an explosive charge of 1.47 lbs. The
difference in blast effect between the two rounds was fairly
significant, but the 76mm HE round still remained effective against
soft targets. Ammunition: Ammunition
storage for the M4A1(76)W Sherman was drastically changed to improve
safety in the fighting compartment. A wet storage system was developed
and placed in all of the newly redesigned M4s. The ammunition storage
racks were relocated from the sponsons to the hull floor, which was
below the turret floor. The new racks were filled with water so that if
the ammo racks were hit, the surrounding water would rush into the
racks and stop the ammunition from catching fire. A wet storage system
was also developed for the turret ready rack on the turret floor. The
lower ammunition racks were divided into 2 separate spaces, one on each
side of the driveshaft had 7 racks that contained 35 rounds and the
other side had 6 racks with 30 rounds. The hull ammunition racks
contained a total of 34.5 gallons of water. The ready rack held six
rounds and was filled with 2.1 gallons. The new wet storage system
proved itself to be a very effective way of stopping the ammunition
fires that had plagued the earlier M4 series of tanks.
M4A1(76)W Type Amount 76mm
71 .50
caliber
600 .45
caliber
900 .30
caliber
6250 Hand
grenades
12 2”
Smoke mortar 12 Armor
& Protection
M4A1(76)W: Type: Turret:
Cast Homologous Steel Hull:
Cast Homologous Steel Thickness and Angle with Vertical: Hull Front: Actual Thickness Effective Armor at 0 degrees (T/cos v) Upper: 2.5 inches (63.5 mm) at 37-55 degrees 80-110 mm Lower: 4.5-2
inches (114.3-50mm) at 0 to 56 degrees
114 - 91 mm Sides:
1.5 inches (38mm) at o to 10 degrees
38 mm Back:
1.5 inches (38mm)
38 mm Top:
0.5-0.75 inches Bottom:
0.5-1 inches Turret: Gun
Shield
3.5 inches (89mm) at 0 degrees
89 mm Front:
2.5 inches (63.5mm) at 40-45 degrees
83 mm Sides:
2.5 inches (63.5mm) at 0-13 degrees
63.5 mm Rear:
2.5 inches (50mm) at 0 degrees
50 mm Top:
1 inches (25mm)
25 mm Engine and Suspension: Engine: The
M4A1(76)W was equipped with the Continental R975 C4 air-cooled radial
engine instead of the Continental R975 EC1 that was used in the early
M4A1. The redesigned C4 engine used bigger radiation chambers and
aluminum exhaust manifolds to decrease the amount of heat build up in
the engine compartment. The super charger ratio was decreased and a
different carburetor was used in order to increase reliability and
power. These changes to the engine resulted in an increase in max
horsepower from 400hp to 460hp. Tank Engine Horsepower Max. Speed M4A1(76)W
Continental Radial 460 hp
24 mph Suspension: The
suspension for the majority of the M4A1(76)Ws built was the vertical
volute spring system until the HVSS suspension replaced it. The new
HVSS suspension for the M4A1(76)W did not appear until very late in the
war. Tank
Ground Pressure (PSI) M4A1(76)W
14.5
M4A1(76)W
HVSS
11.0
Miscellaneous
Equipment: The
M4A1(76)W was supplied with many different pieces of equipment. Each
tank was equipped with an SCR-508 radio that was used for communication
between tanks in a platoon. The platoon commander’s tank was also
equipped with an SCR-506 radio that was used to communicate with HQ.
The SCR-508 was located in the rear of the turret and the SCR-506 was
located in the right front sponson. Some of the M4A1(76)Ws might have
been equipped with the SCR-528 or 538 in place of the SCR-508. The
communications network allowed all crewmembers to communicate with one
another during an operation. Each crewmember was equipped with a set of
earphones as well as a voice microphone that plugged into the
inter-phone system that was part of the radio. Each
M4A1(76)W was also provided with 2 CO2 fire extinguishers, a 10 lb.
fixed fire extinguisher and a 4 lb. portable fire extinguisher exactly
the same as the M3. The crew used the fire extinguishers to extinguish
non-catastrophic fires inside of the vehicle. The M4A1(76)W was also provided with 5-M3 .45 (grease guns) caliber sub machine guns and 12 hand grenades. The M4A1(76)W also was equipped with a M3 smoke mortar that was fixed in the turret roof. The smoke mortar was used to quickly fire smoke grenades in order to conceal the tank from incoming direct fire. Total Production Tank Number Produced Production Dates M4A1(76)W
3,426
Jan 1944 – July 1945 A
little over a third of the M4A1(76)Ws were shipped to Great Britain
under lend-lease agreements. Tank
US
Great Britain
Soviet Union
Other M4A1(76)W 2,096
1330
0
0
COMBAT
IN THE M4A1(76)W: In
late April of 1944 the M4A1(76)W became available to the US troops that
were preparing for the D-day invasion of June 6. It was decided that
there was not enough time to properly train the tank crews in the use
of the new tank before the invasion, so the US troops went ashore with
the older 75mm-armed M4A1s and M4A3s. They immediately encountered
German Tigers and Panthers in the bocage of Normandy and found that the
75mm gun was ineffective against these heavy German tanks which
resulted in heavy losses for the US armored divisions and battalions.
The tankers started to demand the 76mm armed M4A1s to meet the threat
of the German Panthers and Tigers. The final demonstration of the 76mm-armed Sherman was performed on June 12, 1944. Lieutenant General George S. Patton and Major Generals Grow and Oliver observed the demonstration but were reluctant to accept the more powerfully armed new tank. In fact Patton went so far as to require that a separate tank battalion be formed to combat test the new tank. This new tank battalion was never formed because US tank crews’ demands for the new 76mm-armed Shermans became too overwhelming to ignore. Three hundred of the M4A1(76)Ws reached the Normandy battlefield by the end of June, 1944. Significant losses of tanks and crews were attributed to the refusal to issue the better battle prepared M4A1(76)W. The
M4A1(76)W would be the first 76mm-armed Sherman to be issued to the
troops in Normandy. It was received with great anticipation, but soon
became a minor disappointment. In its initial engagements with the
German Panther, the M4A1(76)W still proved to be under-armored and
under-gunned. But the M4A1(76)W was a much better tank than the older
M4s, M4A1s, and M4A3s and the crews and commanders immediately
recognized this. Every armored division and battalion in Europe
demanded as many of the 76mm-armed Shermans as they could get their
hands on. It was initially planned that each tank unit in the ETO would
be armed with 1/3 of its tanks as 76mm armed Shermans, but by the end
of the war, over 1/2 of all Shermans in the ETO were armed with the
76mm gun. The
new M4A1(76)W proved to be a much better tank vs. tank weapon than any
of the previous 75mm armed Shermans. In engagement after engagement the
new tank proved to be a match for any of the lighter Mk.III or Mk. IV
German tank variants and even had a good fighting chance against the
much heavier Panther. Below is a description of a battle between Task
Force Kane with elements of the US 3rd Armored Division
versus the 2nd SS Panzer Regiment on December 24, 1944
during the Battle of the Bulge. The two Shermans that are described
below are both M4A1(76)Ws which the 3rd Armored Division was
very fond of. The description is taken from the book. “Freineux and
Lamormenil” by George Winter. (I will be making a historically based
scenario of this battle once the game is released) “Standing
in the turret, of D-31, parked behind the stone wall, Jim Vance
recalled “All at once I observed an infantryman running toward my
tank. He jumped up on my tank and told me that 4 German tanks were
coming up over the hill to our left front. I alerted the driver to
start the engine and I traversed the turret to the left so I could take
the tanks under fire as soon as they came in view”. As the Panthers
approached across a rising snow covered slope and reached its crest the
Americans opened fire and Erich Heller’s panzergrenadiers jumped from
the tank decks, seeking cover in a nearby ditch. The gunfire was coming
from the Sherman of Corporal Vance, hidden behind the church wall.
Vance standing in the turret recalled “Shortly I observed the 4
German tanks coming across the hill with their flank to my position.” Without
Lieutenant Myers, who was at this moment was attending the officer’s
meeting, to call down firing directions, gunner Vance was on his own.
Firing his shell found the mark, striking oberscharfuhrer Pippert’s
Panther and forcing the Germans to bail out. With
one score, Vance maintained his poise. “When I saw I had hit one of
the attacking tanks, I came up from my sights and fire controls to
locate another tank. I picked up the second tank and immediately went
back to my sights and fired. Again the round hit and I saw the tank
become enveloped in fire and smoke.” Fritz Langanke, standing in the
open hatch of his panzer approached Freineux, looked back to see
Pippert’s tank abandoned and now watched as Untersturmfuhrer Kurt
Seeger’s Panther burst into flames. Although struck in the front,
where the PzKpwf.V was most heavily armored, Fritz Nolte, Seeger’s
gunner realized, “We received the hit in the underside plating at the
front of our panzer. Due to the slope of the terrain we presented
our weak spot.” This was exactly where Vance’s shell struck.
Langanke saw Seeger leap from the burning Panther but he did not notice
that it was Nolte who “pushed Seeger out of the turret and sprang out
behind.” Vance after disposing of the Panthers of Pippert and Seeger,
had located Kirchner’s vehicle and went back to his sight but before
he could pull the trigger, saw that the German was hit. “By the time
I cam up looking for the fourth tank, I was not able to locate it.
About this time he located my tank or the vicinity where the fire was
coming. The 4th German tank fired and hit the wall just to
my right front but didn’t hit us. Since I had not been able to the
remaining German tank, I had the driver back behind the church out of
the line of fire.”…
…Langanke’s
gunner continue to fire, shells striking close to where Sergeant Reece
Graham’s Sherman was position behind a stone wall. Graham’s memory
of this is clear, “I saw a flash from the panzer, the shell hitting
the building near the eve of the house, sending debris all over us. The
panzer then fired another round and missed, hitting the same area.
Returning fire, Graham’s gunner got off two or three rounds but was
unable to score a hit since the German was in a depression … “I
then looked to the right across the valley and saw a flash from another
panzer about 2000 yards away. I then gave the gunner orders. “Right
front! Right front! Range 2000! Fire! After firing I saw the AP with
tracers in direct line, but short. I then ordered the gunner, ‘Up 2!
Fire!’ The second shell went straight into the back of the panzer and
it started burning. I was watching it with field glasses and to my
surprise saw another panzer move from right to left behind the burning
tank. I then gave the gunner orders. ‘Left! Up 2! Fire!’ The shell
went straight in to the rear.””(Winter 34-35) The
advance of the 2nd SS Panzer Regiment along this route was
halted partially by the Shermans of Vance and Graham. The 2 M4A1(76)Ws
stood their ground and stopped a superior force from advancing into the
town of Freineux. At the end of the battle 8 Shermans and 8 Panthers
were totally disabled or destroyed. The
above battle shows that the M4A1(76)W could kill the highly regarded
German Panther tank. The Sherman was at a distinct disadvantage in a
standup long-range tank duel against the Panther, but as the ranges got
closer, the odds become more even. US tank crews learned quickly in battle and developed tactics to help deal with the heavier German tanks. Flanking maneuvers were typically used to get in shots at the weak armor on the sides of the Panther. US tank crews also added armor to the fronts of their Shermans in an effort to negate the Panther’s frontal armor advantage. Tank crews began welding double 1-inch plates to the fronts of the M4A1(76)W to give additional armor protection. These modifications became typical in the later stages of the war especially on 3rd Armored Division M4A1(76)Ws. The uneven plate on the cast hull M4A1 made this job difficult, braces had to be welded in order for the plates to be secured at the edges. This and other armor modifications of the Sherman tank in the ETO will be covered in a future article. The next article will cover another of the 76mm armed Sherman variants the M4A3(76)W and M4A3(76)W HVSS or “Easy Eight”.
References: Bando, Mark, “Breakout at Normandy”. MBI Publishing, Osceola, WI 1999. Cooper, Belton Y., “Death Traps”. Presidio Press, Novato, CA 1998. Culver, Bruce, “Sherman in Action”. Sqaudron/Signal Publications, Carrollton, Texas 1977. Ford, Roger, “The Sherman Tank”. MBI Publishing, Osceola, WI 1999. Hunnicutt, R.P., “Sherman: A History of the American Medium Tank”. Presidio Press, Novato, CA 1994. Winter, George, “Freineux and Lamormenil”. JJ Fedorowicz Publishing, Winnipeg, Canada 1994. Zaloga,
Steven J., “The M4 Sherman at War”. Concord Publications, Tsuen
Wong, Hong Kong 1996.
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