oh it's very true! generally when a bullet enters the body the damage it does spreads out like a cone from entrance to exit as more displaced material is accelerated and the shockwave travels outward. that's why the exit wound is generally many times larger than the entrance wound. a large enough round at a high enough velocity will start taking chunks out of people. that's why many were concerned the m16 wouldn't have enough stopping power when it was first being brought to the battlefield, it used a smaller round than the ak-47. it's not about the size of the bullet, it's about the amount of energy it can impart into the target. a heavier, wider round will create a much larger wound channel. the difference in damage done is much greater than the difference in the size of the bullet.

there are also a variety of specific types of bullets that can affect the wound created and the damage done internally. for example, in smaller, slower rounds that might struggle to create this expanding wound channel effect, they might use hollow point bullets. bullets that are made to expand and/or break apart after impact. creating a larger wound and transferring the energy of the round into the target's organs better.

generally, you can expect that anyone using guns designed to kill humans to be able to damage an area at least 4 times the size of the bullet with every shot. often more, sometimes less. so when you think about getting shot and whether it will hit your internal organs imagine the bullets are more like softballs. because that's the size of the exit wound they'll create. that is why i say it's generally unlikely that you won't fall when shot with intent to kill. i do specifically man using a weapon of war, not a .22 backpack rifle. honestly, people get shot with small caliber handguns often enough. they probably usually don't need to fall over. might feel like it though. i know i tend to sit down when I'm hurt badly enough.

uhh... I'm not a gun nut btw. i generally support sensible gun control and would even like to see something like Australia's method thought about for here (America). I'm just autistic and blame mythbusters for sending me down that rabbit hole when i was younger.