The US M10 was the most produced US tank destroyer of WWII. The British M10s were called Achilles IIC because of the modification of the main gun from a 3 inch gun to a quick-firing British 17 Pounder. The conversions took place at the Royal Arsenal at Woolwich. The Mk. IC had a diesel engine while the Mk. IIC had a gasoline engine. Even the gun of the Mk. IIC was having difficulty against the heavy armor of the German Panthers and Tigers. Gradually the M36 Jackson with its heavier armor began to take
over from the M10 and Achilles.

The 773rd was formally made a TDB (Tank Destroyer Battalion) in December 1941. The unit arrived in Normandy with their M10 TDs on August 8th 1944 and saw its first battle on the 17th. They took up position at Argentan at the southern tip of the Falaise pocket and over next 4 days they destroyed 41 tanks and 80 other vehicles winning them the Presidential Unit Citation. On January 6th 1945 the unit moved north to the small village of Oberwampach Luxembourg, just east of Bastogne Belgium. On January 17, 1945 the battalion destroyed a large number of 1st SS Panzer Division vehicles that brought the total number of tanks destroyed to 102. This made them the first battalion to break the 100 mark. On January 30, 1945 the unit crossed into Germany and part of the unit went to Czechoslovakia. When the war had ended the battalion had seen 254 days of fighting with 356 casualties but not before they destroyed 138 tanks and SPGs and over 100 pillboxes. They managed to capture over 2,000 enemy soldiers.