[NOTE: I converted AOS' '17lbr' to '17pdr' since that's a bit more "well known" for clarity of reading.]
Andras Schneider
Old Friend
Posts: 118
(6/8/06 15:43 )
Re: Soviet vs US in 1945.
Here's a summary I wrote based on Osprey's 'M4 (76mm) Sherman Medium Tank 1944-65'
US Army Ordnance began working on the 76mm gun in early 42 on its own initiative. While there were several 76mm guns already in service, the most likely weapon was the M7 Heavy Tank gun, this gun was too large to fit into a Sherman sized turret. The T1 gun was developed to use the same projectiles, but a shorter case. To avoid confusion, the M7 gun was labeled ’3-inch’ and the new T1 as ‘76mm’. At first the T1 had a barrel 57 calibers long, but this was too long and it was cut back to 52 calibers.
Unfortunately, though the new gun could penetrate almost 1 inch more then the 75mm weapon, it did not offer the same anti-tank performance as other comparable guns. The new gun only had a 3.6 lb propellant charge, the Brit 17pdr had almost 9 lbs, the 7.5cm German gun had 8.1 lbs.
Likely Penetration at 500m
76mm- 116mm
17pdr-163m
7.5cm-168mm
After 1944 with improved ammo
76mm-208mm
17pdr-256mm
7.5cm-234mm
Several concerns were raised with the gun in other areas- Large muzzle blast and dust cloud, smaller explosive charge in the HE shells, and no smoke shells. The Tank Destroyer Battalions were supposed to be the primary offensive anti-tank arm in the US army, and the M4 medium tanks were to fight infantry, artillery, and exploit breakthroughs into the enemy rear. Since the TDs already had the 76mm gun, objections were raised about the unsuitability of the 76mm gun to infantry support missions. During the war, 70% of all tank ammunition fired was HE, 20% AT, and 10% smoke. It was recommended that 1 tank in 3 be armed with the 76mm gun, either one company per battalion, or one platoon per company.
The Brits decided to arm 2 tanks per troop with a 17pdr. They also offered to ship 200/month 17pdr guns to the US for installation on US tanks in Aug 43. Trials between the 17pdr and the new 90mm gun in March 44 showed that the 17pdr had better penetration performance then even the new 90mm gun. However by the time these trials took place, 76 and 90mm ammunition was already in production and any new tanks would not be available until after Normandy. Ordnance was also developing new HV ammo for the 90mm gun at that time.
By Normandy, There were 200 76mm armed Shermans in Depots in Britain, but there was no plan to distribute them to the units involved in the invasion. Most of the commanders were reluctant to see the 76mm gun replace the 75mm gun in any significant quantities. While the 75mm could not penetrate the Panthers glacis or mantlet at any range, the 76mm also could not penetrate the glacis at any range, but could pierce the mantlet of the Panther at 200yds. US intelligence did not expect the Panther to be deployed as a Medium tank with the PzIV, but as a heavy tank like the Tiger. The numbers of Panthers encountered in France was a significant shock to the combat arms.
However, by September, the ‘Panther Problem’ appeared to be much less urgent, the US believed that most of the Panthers had been knocked out. A few days later 4 newly formed Panther brigades were crushed conducting a local offensive by 75mm armed tanks due to superior tactics and training on the part of the US forces.
An additional problem was that units were short of tanks across Europe, 335 tanks short of ToE by the end of September. Ordnance was reluctant to switch to a new tank line and worsen the tank shortage.
In August 1944, a new HV round was issued to the existing 76mm units. This round could pierce a Panthers mantlet at 1000yds, but still bounced off the glacis. Production of the tungsten cored ammunition was never able to meet demand and distribution was hardly more then one round per tank per month on average. By February, each 76mm tank had received only 5 rounds of HV on average.
After Ardennes however, there was a marked change in opinion about the 76mm tanks. In January, the 12th Army Group formally requested that no more 75mm Shermans be sent to the ETO and in February stopped bringing 75mm tanks up from repair depots. By April 600 75mm Shermans had accumulated in rear depots. Some of these were sent to Britain to be converted to 17pdrs but never reached the front before the surrender.
2095 76mm armed Shermans were sent to Russia. The M4E2 was a popular tank, called the ‘emcha’, a contraction of M-Chetire (M4 in Russian). The M4 equipped the 1st, 8th, and 9th Guards Mechanized Corps.