Bullets, heavy and light, small and big, hard and soft, are designed for different things.
I light 100 gr 243 at 3000 fps through the lungs of an antelope would turn those lungs into the consistency of coffee grounds.
A heavy 180 gr 30 cal. bullet will pass through, maybe open up, leave an exit hole bigger then the entrance, leave a blood trail, and from what I seen this critter will run much further then the one shot by the 243.
A 100 gr 243 at 3000 fps would probably blow up on an elk before it got the penetration needed to do the damage.
The 180/30 cal. bullet expands more on this elk there for doing more damage, plus it has the penetration.
Lets move away from animals. I shoot a lot of bowling pins. In practicing a couple weeks ago, for kicks I shot a bowling pin with a 32 gr 204 going over 4000 fps. It went plum through the pin, hardly moving it at all.
Then I shot a pin with my 45 ACP, 230 gr cast lead bullet going a bit over 700 fps. It didn't totally penetrate the pin, but it picked it off the table and deposited it on the ground about 6 feet behind the table.
Don't mean the 45 is better, I sure wouldn't use it on prairie dogs.
It means nothing more then they are different. They have different missions.
Shoot more then one venue so I need more then one gun and more then one bullet style.
Same with vehicles. If I'm going across country, staying in motels, I 'm not taking my F-250 HD Diesel. I want a small car with better gas mileage. But if I'm going to haul 10 or so large hay bales for my horses, I certainly wont pull it off with my wife's little Mustang.