It is interesting.
When it comes to defeating multi-ply armor fabric, while velocity does play an important role in doing so, supersonic velocity is not required especially if projectile nose geometry and material selection are chosen correctly.
The Soviet PSM 5.45x18 7N7 with a muzzle velocity of just 315 m/s offers surprisingly efficient penetration of Kevlar29 panels due in large part to its hardened penetrator and nose geometry.