M855A1 is a small-calibre high-velocity rifle bullet with the structure of the new type of small-and medium-calibre armour-piercing projectile. Compare to its predecessor

M855/SS109

M855A1 has enhanced penetration performance against hard targets and lethality against soft targets. To study the penetration performance of the new 5.56 mm M855A1

numerical simulations of the process of M855A1 penetrating structural steel target and armoured steel target at different ranges were carried out using the finite element software ANSYS/LS-DYNA. The deformation and damage evolution of the round and steel target during penetration were analysed

and the relationship between range and maximum penetration thickness was fitted as a function

with a fitting accuracy higher than 99%. The results showed that the M855A1 round can meet the demand for penetration performance against hard targets of modern high velocity small-calibre rifle bullets

and its structure is more efficient in utilising the kinetic energy of the round under low-velocity and thin-target conditions.