Chemical warheads used as tank ammunition. Shown are the HE and HESH shell (HEAT will be discussed in latter part)

The one which has a pointed end is a standard HE ammunition. High explosive ammunition is commonly used against open-topped vehicles (eg. early SPAAs, US tank destroyers). However, large fillers can cause overpressure even on well-armored targets. HE ammunition is used on aircraft as well.

Example of HE ammo: the Soviet OF-540.

The one which has a rounded end is a high-explosive squash head, or HESH/HEP. HESH shells are similar in respect to high explosive anti-tank rounds, however the head of this round is like modelling clay being hurled into a wall; deforms, and while it takes contact to a hull it causes explosion to a hull interior. Still used as a niche ammunition today.