The bulk of this total went to US Army tank destroyer battalions, and in early 1943 there were 106 active battalions. But as the war continued their number gradually decreased when it was realized that the tank destroyer concept as an arm separate from the rest of the American armoured forces was wrong and as it emerged that the best counter to a tank was another tank. But the tank destroyer force remained in being until the war ended, most of the battalions being used in Europe. By the end of the war many of the M10s and their associated equipment and towed guns were being used more as assault forces than tank destroyers. The M10 was the primary equipment of these battalions and was used not only by the US Army but by the British (who knew the M10 as the Wolverine) and later by the French and Italian armies. In combat the M10 proved to be less than a complete success, for despite its thin armour it was a large and bulky vehicle and as time went on the gun lost much of its anti-armour effectiveness. But the M10s were still in use when the war ended. By then the British had re-gunned many of their M10s with 17-pdr guns and re-named the type Achilles.
A number of M10s and M10A1s were supplied to Britain in 1944 where they were designated "3in SP, Wolverine". These were issued for combat service to British units in Italy and France; most were converted from late 1944 by replacement of the 3in gun with the British 17pdr gun, producing a much more potent tank destroyer than the M10 in its original form. In its new guise the vehicle was designated "17pdr SP. Achilles Mk IC". M10A1s similarly converted were designated Achilles Mk IIC. The original mantlet was retained in this conversion. First in service in limited numbers in 21 Army Group in early 1945, the Achilles was used for many years post-war by the British. This was a most successful conversion. Vehicles not converted were altered to gun towers by the removal of the turret and at least one of these was tested as an experimental mine plough.