M3 was based on a howitzer that had been built in prototype. After the Germans used the short barrel 75mm gun in the battle of France, the US Army… developed the Lee using mostly existing blueprints to get a 75mm gun into the hands of the troops for training only, as quickly as possible. In the meantime they started work on the Sherman, which was intended to be a combat tank.The Lee / Grant was never intended for actual combat operations but the British and Soviet Union wanted tanks so badly that the US sent them to those nations to use in combat. Tanks are complicated and in those days it took a long time to draw and copy blueprints …
Not quite the way I understand it. Several key components, but not the same total perspective.
Yes the US Army was pretty impressed by the Pz IV in France. In fact most of what the US Army got in WW2 was tuned to respond to what the US Army observed of the French compaign.
And yes, the blueprints, and limited drafting (and engineering) resources, were a key limiter to the M4 program.
But …
"M3 was based on a howitzer that had been built in prototype."
Not sure how to understand that statement. The M3 Medium tank (Lee and Grant) used the M2 75mm gun for the most part, with only the last production lots going to the M3 75mm gun. Not sure if we are referring to the M3 Medium or the M3 gun in the statement.
In any case the 75mm M2 or M3 were not howitzers, but guns. Tank guns, to be specific. New designs built to fire the same ammunition as (and largely to duplicate the performance of) the M1897 (and various sub-versions) 75mm gun that the US built under license from the original French design.
This was a standard US Army light artillery piece. There was also an anti-tank gun made from it. It was mounted in the M3 Tank Destroyer. Millions of rounds of ammunition were in inventory, and to all appearances in 1940/41 it was a very good choice for both HE and AP work. The original artillery piece was an L36. The M2 tank gun was a bit shorter. The M3 tank gun was a bit longer.
The US Army Ordnance (and the Tank Board, if it was formed yet?) wanted to go from the M2 Medium, with it's 37mm gun, directly to a medium tank with the new 75mm gun in it's turret. It was the British who intervened, their purchasing commission strongly urging the fastest path to fielding a medium tank with a 75mm gun. The limiting factor was in fact the turret ring -- tooling to machine a large enough turret ring for the new gun would take a bit of time, delaying the production delivery ramp by a few months. Even 8 weeks delay was too much to the Brits, and they asked for any approach to speed delivery.
The M3 medium was seen as an interim solution. The fact that it would put a tank in the hands of the US Army for training was a side benefit. The US Army troopers could have trained on M2 Mediums just as well (in fact better, due to the more conventional crew tasking), but everyone was loath to build more M2s as no one expected them to be useful for combat. Since the Brits were so gung-ho to get the proposed M3 Mediums, the US Army decided to build enough to supply not only the Brits but the US Army's training needs as well.
And THEN the limits of manpower came into play.
The M4 Medium, which had been conceived prior to the initiation of the M3 Medium, had to wait while all of the drafting and design manpower went into the M3 program. So getting the M3s 8 weeks sooner led to 8 or 9 months delay in getting the M4s.
And during that time the demand for M3s went up up up. Because the Brits wanted every delivery schedule sooner, not just one. And the Russians were screaming for tanks too. And the US wanted to get factories running and chunking out tanks and tank engines and tank gun barrels and tank suspension bogies etc. etc., so the tap was turned on and out they flowed.
It is true the US Army never intended to take the M3 Medium into combat. The plan all along was to use them for training until M4s became available, but to go into battle in M4s. Then, as M4s did start rolling off the line the Brits cried out for as many as could be provided, and in fact US units equipped with M4s had to revert back to M3s prior to the Torch landings to allow their shiny new M4s to be shipped off to Monty for El Alamein.
The US wound up building several thousands of M3 Mediums. All of this for a tank that was only put into production to save a few weeks on an initial delivery schedule.
Or so I understand.
-Mark
(aka: Mk 1)
examines another house in this series.
