Riich 35019 1/35 US M1 57mm Anti-Tank Gun Early Version on M1A3 Carriage 5 figures

Aberdeen Proving Ground began evaluations of the first test guns, designated the T1, around August 1, 1942.The first test guns had a bore length of 57 calibers and when tested on an M4 tank; it was found that the long barrel caused balance problems Another T1 test gun was produced with the barrel shortened to 52 calibers and a counterweight added to the breech guard to improve balance. By August 17, the Ordnance Department had classified the test gun with the shorter barrel as the 76-mm M1 and set up the precedent for the designation of M4 tanks armed with the gun to include "(76M1)".