Being overgunned can cause a number of flaws in your shooting form and negatively effect your accuracy on game.
Shooting a gun with too much recoil can cause you start flinching, jerking the trigger, or even closing your eyes at the shot.
Nobody likes recoil... nobody. So it should go without saying that the more your gun recoils, the more it will negatively affect your accuracy. However, there are still a lot of hunters out there toting rifles that they are afraid to shoot when they would see better success with well placed shots from a lighter caliber rifle.
For example, you don't need a .300 Winchester Magnum to shoot whitetails or a .338 Lapua to down an elk. The extra power these cartridges offer is great until it starts affecting accuracy, at which point you'd be better off with something smaller (think .243 or .270.) Consistently placing shots in the kill zone with a lighter rifle will help you kill more game than relying on the shock factor of a big boomer.
It's easy to fall into the "bigger is better" trap with big game cartridges. But every hunter has to be honest with themselves on how much recoil they can handle and choose a gun that fits the bill for their situation. Small-framed men and women, children, and those new to firearms will be particularly sensitive to recoil and should choose their weapon accordingly.
Gun writer David Petzal once wrote that "the IQ of a rifleman is inversely proportional to the size of the cartridges he shoots." While this isn't always the case, I think it's a good rule to keep in mind when choosing a hunting rifle.
I have to admit I fell down the rabbit hole of the overgunned hordes before trading in a .300 Winchester Short Magnum for a more mild mannered .270 Win. In four years of hunting, I missed more shots with the .300 WSM than I had in 17 other seasons combined. After switching to the .270 Win., my success has been nearly 100 percent.
If you choose to shoot a big game caliber on the lighter side, be sure to use heavy, well constructed bullets to provide the expansion, weight retention, and penetration you need to bring down big game, then shoot with confidence that the bullet will land where you want it to.
By making an honest assessment of how much recoil you are comfortable with, you'll be more accurate and more lethal in the field.