M3 Medium Tank, pros and cons?

I read different sources and some of them describes the M3 as more or less crap used only in lack of a better tank, while others describes it as a more decent tank.

What do you think? What was the pros and cons of the M3 and how do you think it compared to it's most common adversaries?

 

The biggest Pro for the M3 is that is was there. It put a 75mm armed AFV at the front line at a point when it was desperately needed. They were nicknamed ELHs, (Englands Last Hope) prior to El Ala mien.

The 75mm gun had a outstanding HE round extremely useful against AT guns, which at the time were more of a danger then opposing tanks, and it could still deal with most German tanks. In this regard it was a better tank then the 40, and 57mm tanks prior to its introduction, even if the 57mm tanks had better AT performance.

Of course the sponson gun had limited traverse, it was far too tall and vulnerable, the armor was weak, cross country performance left something to be desired etc. I believe the Russians nicknamed it a Coffin for 5, or something like that.

It was inferior in all ways to the later Sherman, but it was there, in large numbers, before the Sherman, thats what mattered. The worst tank in the world that is avalaible is much better then the best that you wont have till next year.

In the Pacific theatre, the high Ammo storage, and 75mm gun still gave good service for a long time.

 

ruskies called it coffin for 5 brothers

but a you noted, it was there when you need anything, and it really helped the allied effort until the sheman showed up!!!!

 

It was 7 brothers I believe, but that was during the Battle of Kursk where the Germans had as much technological advantage over the Soviets in the matter of armour as they would ever have. Before or after.

I thought we could, just for the sake of discussion, ignore that the M3 was largely a stopgap measure declared 'subsistute standard' by the U.S. Army in October 1941 already, and compare it to other tanks of the same period by it's own merits.

 

Hunnicutt goes over the combat performance of the M3 pretty well in his book. With the exception of the Long Barreled Mark IV Panzer, they actually outclassed the Mark III and IV tanks they faced in the desert (They had rough parity with the "Special Panzer III mark J). Rommel's own notes state the 75mm gun of the M3 was a drastic shock. The M3's armor, while not too exceptional, actually gave good protection against the low velocity 75mm and 50mm guns they usually faced, at least at long range.

The long range of desert fighting reduced the disadvantage of the hull mounted gun, at least in offensive operations. Defensively the tank could not use a hull down position.

Lets compare it to other British tanks at the time.

The Crusader I.
http://www.onwar.com/tanks/uk/data/crusader1.htm
HP ratio was 17.8HP/Ton, better then the M3's 14.3
http://www.onwar.com/tanks/usa/data/m3med.htm

Turret armor for the Crusader I was just 20mm, the M3 had 50.8mm on the turret, and about the same on the hull. The crusader I had just 26mm on its hull, plus a lamination of 14+26mm on the mostly vertical portion, although the sloped varied making a comparison trickier.

The PzKpfw III Ausf. L had a HP ratio of 14, comparable to the M3. Its armor was similar, about 50mm, but tended to be less sloped, of course it was not as high.
http://www.onwar.com/tanks/germany/data/pz3l.htm

So the M3 had better armor protection, inferior mobility then its contemporary british tanks.

As far as firepower, the lack of a HE round for the 40mm on the Crusader was a major weakness. As far as raw AP performance goes.
40mm gun
http://www.freeweb.hu/gva/weapons/british_guns2.html

75-mm Tank Gun M2
http://www.freeweb.hu/gva/weapons/usa_guns5.html
See the APCM61 projectile, (This was not used in the early fighting, however, captured german 75mm projectiles were carefully lathed down and assembled into US cases for combat. It gave identical AP performance to the APC M61, with the added bonus of a explosive filler.)
The 75mm could penetrate more armor at 2000 yards (46mm) then the 40mm could at 1000 (45mm).

Compared to the 50mm German guns, the 75mm still looks better, plus it had the better HE round.
http://www.freeweb.hu/gva/weapons/german_guns3.html

Only against the L43 and later 75mm gun does it finally look bad.
http://www.freeweb.hu/gva/weapons/german_guns5.html

So even viewed on its own merits, its had some superiority to the Crusader tanks it fought with, and the Mark III and IV Panzers it faced.

 

To give a specific example, lets say a M3 faces a PzKpfw III Ausf. J at 1000 yards. Its 75mm gun can penetrate 2.2 (55mm) of homogenous armor, or 2.4in (60mm) of Facehardend armor, both at 30 degrees. (The facehardened data is from Hunnicutt, page 562.)


The Ausf J have 50mm of hull armor (21 degrees slope), 30mm of turret armor (15 degree slope.) and 50mm of Mantlet Armor (0-45 degree slope)
http://www.onwar.com/tanks/germany/data/pz3j.htm
(Note the slope numbers are reversed, here 90 degrees is vertical, so to compare to the 30 degree performance mentioned, you have to convert the numbers, ie the turret armor 75 degree slope is 15 degrees.)

Bottom line is the Ausf J is vulnerable for the most part to penetration.


The Ausf J's 50mm L42 gun can't penetrate more then 37mm at 1000 meters (about 1100 yards) and even at 500 meters it can only penetrate 55mm with rare APCR ammo (More common APC ammo can penetrate 47mm). The M3's 2in (50.8mm) of hull and turret armor (sloped at between 30 and 45 degrees) would give good protection past 500 yards. A portion of the front hull only has 1.5in of armor, but its sloped at 53 degrees.

So in a long range duel, the M3 actually has the advantage.

 

I notice that one of the main features of the M3 has not been mentioned - it had 2 guns. The 75mm was not really the tank-killer, the 37mm was. However, at longer ranges the 75mm had the edge here, I think.

Bottom line, the M3 was a bit too tall, and the rivetted armour they had presented the usual issues, but they were clearly superior to the majority of British, German and Italian tanks in North Africa when they arrived.

 

I believe that was the original intent, for the 37mm to be the anti armor gun with the 75mm shooting HE, but it was quickly realized that the 75mm was better at the anti armor role as well.

Per Hunnicutt, against facehardened armor the 37mm had the following performance at 30 degrees.

Yards
500 1000 1500
1.8 1.6 1.5

75mm
2.7 2.4 2.2 m61 shell
2.3 1.8 1.3 m72 shell

As long as M61 was available, (Or the captured german rebuilt ammo), the 75mm was the real tank killer as well.

 

Sorry, my bad memory

 

No, I think your memory is correct, at least so far as the 75 was considered the HE gun vs the 37mm as the AT gun. At least I've read that several times as well. It just turned out the the 75 ultimately was better at both.

 

I've seen photos of Russian "Lend-Lease" M3 mediums that showed a long-barreled 75mm mounted in the hull sponson. It appears noticeably longer in length than the standard Grant/Lee fielded by US and British tankers.

Tim

 

Early M3 tanks had the M2 gun, with a 1930 ft/sec muzzle velocity with the APC M61 projectile. Later M3's had the M3 gun, with a 2,030 ft/sec velocity. Presumably the Lend Lease M3's all had the M3 gun.


Hunnicutt page 562

 

The book "Pendulum of War" mentioned teh problem with the 75mm was the solid shot AP round had no cap on it and often shattered when it hit German armor, drastically reducing its effectiveness. Before Gazala the British had actually used Captured German 75mm Shells and removed the caps and put them on the US rounds, thus using modified American Shells with German caps, but with the defeat at Gazala the ammunition was lost and at El Alamein they used the the uncapped 75mm US rounds.

 

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I seems to remember that the M3 had in fact been designed with three turrets ..
one in sponson for the "infantry support "gun
one on top of the hull for the AT 37mm
one on top of the former for a machine gun ( the brits asked for this last to be removed , supposedly )
The same source was commenting on the excellent packaging of the tank for transport and it's wonderful gun who could actually hurt Germans

The whole tank feel very late twenties style and I think , with its high silhouette , it was possibly inspired by the French B1

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