Here’s a little Army-Marine Comparison.

Here’s a little fun fact, most people make Vest cover the whole torso even tho they only cover the chest irl this is more noticeable with modern Plate Carriers and the New PC GEN IIIs. If you did find examples of Vest that cover the whole torso like the IOTV and PASGTs, it’s either because they have soft armor extensions covering the abdomen or its just made out of soft armor entirely.