Knowing the difference between cover and concealment when under attack is of vital importance. Cover is anything that provides varying degrees of protection from gunfire. Examples are brick walls, concrete walls, engine compartments of vehicles, logs, thick tree trunks, trenches, rock formations, a freezer full of frozen food items, hillsides, metal dumpsters, sandbags at least 12 inches thick, 55 gallon drums filled with sand, steel doors, concrete parking barriers and telephone poles as examples. If it can generally stop a bullet it is considered cover.
Concealment provides a place to hide but will not stop gunfire. Examples are walls of a normal wood frame house, small trees, foliage, darkness, bushes, tall grass, shadows, car bodies, behind non steel doors, tables and couches. If it cannot stop a bullet it is considered concealment. Make sure you know the difference; it just might save your life someday.
It’s also important to know the penetrating depths of various calibers at various distances. Things that might provide protection against a 22LR, 9mm, 45ACP, .223, 5.56 NATO, or a 7.62×39 may provide less protection or at times no protection against a .308, 30-06, 7mm Rem Magnum, 338, 300 Winchester, or 7.62x54r for example. And if it’s a 50BMG; well pretty much nothing is going to stop that round. Know your weapons, know your rounds, know the penetration depths at key distances and your odds of survival increase dramatically if the SHTF.
You can take a look at some of my apocalyptic fiction books on the left side of my blog page by clicking on the book cover images. If they interest you then I hope you will consider purchasing a copy.