There’s no shortage of small calibers that look fine on paper—plenty accurate, low recoil, and even decently priced. But once you start asking them to do real work in the field, especially on anything bigger than a rabbit, they fall flat. These are the rounds that punch paper well and maybe drop a squirrel with authority, but they don’t offer enough energy, penetration, or terminal performance to count on for anything with weight behind it. And sure, with perfect shot placement, you can kill a deer with just about anything. But the real question is: can it consistently anchor the animal fast and clean? If you have to hope for a lucky shot, or worse, you’re tracking wounded game into the night, then that cartridge has no business in the role. These are the calibers that make the list—not because they don’t have a use, but because their use ends before anything bigger than a cottontail comes into view.
.22 Long Rifle
Everyone loves a .22 LR—it’s cheap, fun, and deadly accurate out to 50 yards. But once you step into the world of anything larger than a rabbit, that little round hits its limit fast. It doesn’t carry the energy needed to break bone or reach vital organs reliably on bigger game, even with perfect shot placement.
Some folks have dropped deer with a .22 LR, but that’s not a benchmark—it’s a gamble. Most .22 LR loads push under 150 foot-pounds of energy. For comparison, most hunters want at least 1,000 for whitetail. It’s a great small-game and training round, no question. But if you’re carrying it for anything with mass, you’re likely to be undergunned and chasing blood trails you don’t want to follow.
.22 Winchester Magnum Rimfire
The .22 WMR looks like it should bridge the gap between rimfire fun and practical hunting. And to a point, it does. It’s more powerful than the .22 LR and zips out a 40-grain bullet at around 1,800 fps. But even with that boost, it’s still a rabbit-and-varmint round—not something you want to trust on larger animals.
Plenty of folks try to stretch it into predator hunting, and while it can drop a coyote with perfect placement, it doesn’t have the energy or bullet weight to anchor consistently. Penetration suffers past 75 yards, and most bullets are designed for rapid expansion, not deep impact. It looks better on paper than it performs in the field when things get hairy.
.17 HMR
There’s no denying the .17 HMR is a fun little cartridge. It’s flat-shooting, fast, and surprisingly accurate. For prairie dogs and ground squirrels, it’s a dream. But it has no business being pointed at anything larger. The tiny 17- or 20-grain bullets are prone to explosive fragmentation and rarely provide the penetration needed on animals with thicker hide or heavier bone.
Even on foxes and small predators, the .17 HMR can be unreliable. A hit that looks good might splash on impact or fail to reach the vitals. It might look like a step up in some ways, but when it comes to anchoring power, it’s more flash than force. This one should stay in the varmint lane where it shines.
.17 Mach 2
The .17 Mach 2 never took off like the .17 HMR, and there’s a reason for that. It’s built off the .22 LR case, necked down to take a 17-grain bullet. It screams downrange, but it runs out of gas quick. It’s decent for paper and tiny pests, but its energy levels are downright anemic past 75 yards.
You’re talking about a cartridge with around 120 foot-pounds at the muzzle—barely more than a hot .22 LR. It doesn’t handle wind well, can be picky in semi-autos, and tends to explode on impact without much penetration. It might be good for eliminating nuisance chipmunks, but anything bigger should make you think twice before reaching for a rifle chambered in Mach 2.
5mm Remington Rimfire Magnum
The 5mm RRM is one of those oddballs that had potential but never caught on. Ballistically, it’s better than the .22 WMR and even gives the .17 HMR a run for its money. But it’s still a rimfire round pushing light bullets—not something you want to count on when hunting anything that can kick, claw, or run far.
Its biggest downfall was ammo availability and inconsistent support. Even when you can find it, you’re still limited by rimfire performance. That might be fine for groundhogs, but it’s not going to cut it for anything with serious body weight. You’ll get fast expansion, sure—but not the kind of penetration you’d want on a shot that isn’t perfect.
.25 ACP
If you’ve ever seen what a .25 ACP can (or can’t) do in ballistic gel, you know why it’s on this list. It’s barely more effective than a .22 LR, but somehow manages to cost more and offer less velocity. It’s been used in tiny pocket pistols for over a century, but you’re dealing with a round that was never designed to bring anything down fast.
In terms of terminal performance, it’s a dead end. Even rabbits might take off running if your shot placement isn’t perfect. The bullet is tiny, slow, and doesn’t expand much—if at all. It might look cute in a mouse gun, but if anchoring a living target is the goal, there are better options even within rimfire territory.
.32 ACP
The .32 ACP has a bit of nostalgia attached to it. Plenty of European police forces used it decades ago, and it still shows up in older carry pistols. But ballistically, it’s a lightweight. Most loads generate under 200 foot-pounds of energy and don’t penetrate well. It can work in a self-defense pinch, but that’s about where its usefulness ends.
Some folks might think it’s a step up from .22, and maybe it is—barely. But when it comes to anchoring power, especially on animals, the .32 ACP falls short. Expansion is rare, and accuracy past 25 yards gets spotty quick. It might handle a rat, but ask it to do more and you’ll be disappointed.
9mm Flobert
The 9mm Flobert was never meant to be a serious hunting round—it’s more of a garden gun. Think snakes, rats, or starlings in a barn. It’s essentially a rimfire shotgun shell without much shot or powder behind it. Velocity is low, range is almost nonexistent, and pattern density is terrible past 10 yards.
It’s a fun novelty round and has a place for very specific pest control needs. But in terms of anchoring anything bigger than a rabbit, forget it. There’s no punch, no reach, and no consistency. If it weren’t for the charm of old Flobert rifles, most folks wouldn’t give it a second look.
.380 ACP
This one might ruffle some feathers. The .380 ACP is a common carry round, but it’s still marginal for serious use. In short barrels, it struggles to expand reliably and doesn’t always penetrate deep enough to reach vital organs—especially in anything with muscle or thick skin. And while it’s carried more for personal defense than hunting, some still try to stretch its use.
On paper, it can look close to 9mm. But once you account for lower velocity and energy loss through small pistols, the gap widens fast. For rabbits or pests at close range, sure. But anything bigger—like raccoons, coyotes, or even small hogs—you’re going to want something with more gas behind it. The .380 belongs in backup guns, not on your belt for anchoring critters.
.32-20 Winchester
The .32-20 has been around forever and still has a loyal following. It’s a soft shooter and looks great in lever guns. But performance-wise, it’s stuck in the past. With factory loads hovering around 1,000 fps and bullets in the 85- to 100-grain range, it was never a powerhouse.
It can work for small game and might take a deer in very controlled situations—but you better be close, and the shot better be perfect. It’s underpowered by today’s standards, especially compared to modern .30-caliber options. You can squeeze more out of handloads, but it’s still not something you want to rely on for anything that might run far or fight back.
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Calibers That Shouldn’t Even Be On the Shelf Anymore
Rifles That Shouldn’t Be Trusted Past 100 Yards
*This article was developed with AI-powered tools and has been carefully reviewed by our editors.
