Of particular interest to me because Dad was assistant driver / radio operator in an M10 (2nd Platoon, Company C, 640th Independent Tank Destroyer Battalion, Army of the United States; see A History of the 640th Tank Destroyer Battalion). Author Steven Zaloga relates how fouled up US Army armor doctrine was at the beginning of WWII; tanks were considered infantry weapons, expected to keep up with marching troops and to suppress enemy machine guns and bunkers; they weren’t supposed to fight enemy tanks. Fighting enemy tanks was a job for the artillery, and the artillery wanted towed guns, not self-propelled vehicles (which looked too much like tanks). When tank destroyers were finally authorized, they were expected to be light-weight, fast vehicles that scurried around the battlefield shooting up enemy tanks. It didn’t seem to occur to anybody what would happen if the enemy didn’t cooperate with these ideas.

To further complicate things, the Army selected a 3-inch gun as their antitank weapon; this was different from the 75mm gun that equipped medium tanks. After two abortive attempts to field this on a self-propelled mounting (the M3 and M9 Motor Gun Carriages) the Army eventually settled on the M10; this was built on the chassis of an M4 medium tank (the Sherman) but with an open-top turret and lighter armor. It was hurried into production and a major flaw was quickly discovered; the turret was poorly balanced and couldn’t be rotated if the vehicle was on a slope greater than 4°. That, in turn, lead to some “quick fixes”; a 0.50 machine gun was added to the rear of the turret and track grousers were stored there. These didn’t work very well, either; despite being nominally an “air defense machine gun” the machine gun was in a poor position for use against either ground or air targets and the extra weight still didn’t fully counterbalance the turret (unlike the M4 it was based on, the M10 turret didn’t have power traverse and had to be hand-cranked). Finally various counterweight kits were developed and used as both field installations and on new production; these added more weight to what was supposed to be a light-weight vehicle. In the meantime, there was still a push for towed guns; the artillery seized on the fact that very few tank-versus-tank battles had taken place in the North African and Italian campaigns, and some tank destroyer units had their M10s replaced by towed 3 inch antitank guns.

When fighting finally shifted from Italy to France, it was quickly discovered that their weren’t many tank-versus-tank battles in North Africa and Italy because the Germans realized these weren’t vary good tank country and shifted their panzers elsewhere; but they had different ideas in France (once again the pesky Germans refused to cooperate with American doctrine). The 3 inch gun, either as a towed weapon or mounted in the M10, wasn’t powerful enough to defeat the German Panther tank’s frontal armor, and the Army scrambled to find something that was; in this case a 90mm antiaircraft gun (the British and Canadians had already started mounting the 17-pounder gun in there M10). The 90mm got mounted on the M10 chassis in an improved turret (still open-topped) as the M36; these proved adequate against the Panther.

As mentioned, the original placement of the 0.50 machine gun on the M10 made it difficult to use against ground targets; in addition, even though the M10 was based on the M4 chassis it didn’t have a “bow” machine gun or a coaxial machine gun like the M4. To compensate, a lot of M10 crews shifted their 0.50 machine gun to a pintle mounting on the side of the turret and added an additional scrounged 0.30 machine gun on the other side.

As it turned out the whole American tank destroyer doctrine was flawed anyway; the weapon that was most effective against enemy tanks was another tank. American tank destroyers did get a shot at an enemy tank now and then but they ended up usually used in other roles – as direct fire support in infantry attacks, for example, or as conventional artillery for indirect fire (this had been expected and the M10 came with indirect fire equipment; however the gun itself had never been expected to be used for that volume of fire so required frequent barrel changes).

After WWII, a few M10s and M36s soldiered on here and there; a number of M36s were sent to the Yugoslav army and turned up in Croatian and Serbian units during the 1990s Balkan Wars (the original General Motors diesel engines had usually worn out by then and were replaced with Soviet surplus V55 engines; that conversion gives me respect for the ability of Yugoslav mechanics).

One more interesting item; Zaloga notes the M10 is sometimes referred to as the “Wolverine” and the M36 as the “Jackson”; neither of these was an official US Army designation and “Jackson” doesn’t appear anywhere until well after the war. It seems like British M10s were rarely referred to as the “Achilles”, but Zalonga notes the name wasn’t common.

A typical Osprey publication; oriented toward the military modeler. Lots of illustrations, both actual period photographs and color paintings. ( )