Composites and anti-spall liners have rendered that kind of attack almost entirely obsolete against modern armor. The Challenger II was designed with a rifled

Composites and anti-spall liners have rendered that kind of attack almost entirely obsolete against modern armor. The Challenger II was designed with a rifled gun barrel so it could use HESH ammo, and the Brits have been trying to scrounge up the money to replace it with a smoothbore for decades now (I see they finally did last year).