Firing Strain Measurements on 76mm Gun M1E2

Measurements of tangential and axial strain were taken at various points on a 76mm Tube M1E2 while firing the M79 projectile at various pressures from 75 to 115% of normal. Rather high peak strains in both directions were observed at the time the projectile passed, especially near the muzzle. Peak tangential strains or the outer surface due to the rotating band were observed to be around one and one-half times higher than the strain due to the gas pressure, at the thick-walled section; and more than two and a half times higher, near the muzzle.