What makes a good varmint cartridge?
It should be accurate in most factory rifles. It should be flat-shooting, meaning it doesn’t drop too much at longer rangers. It should also have limited recoil to allow for a full day of prairie dog hunting and use a narrow bullet to preserve the pelt as much as possible.
There are lots of popular cartridges that check these boxes, and we’ve covered some of them in previous articles. But there’s one varmint cartridge that I don’t think gets enough love, and even though die-hard varmint hunters have likely heard of it, it’s worth a look even if you only chase the occasional coyote, bobcat, or prairie dog.
That cartridge is the .204 Ruger.
Twenty Caliber?
The .204 Ruger is, as far as I’m aware, the only commercially available 20-caliber cartridge on the market. That means it has a smaller bullet diameter than more common 22-caliber cartridges, but it’s slightly wider than the smallest 17-caliber projectiles.
Why a 20-caliber? Novelty was likely part of the equation. Hornady and Ruger came out with the joint-venture cartridge in 2004, and it’s always easier to sell a cartridge billed as a “first” in any category.
But that’s not the only reason. If you’re trying to make a small, lightweight bullet that won’t cause too much hide damage, you can achieve higher ballistic coefficients by reducing the caliber. This 32-grain .204 Ruger, for example, has double the BC of this 35-grain .22 Hornet (.210 vs. .109). That means the bullet will drop a bit less and be less impacted by wind, two crucial features of a good varmint cartridge.
Of course, 22-caliber bullets can be found with higher BC’s, but you have to bump up the weight, which some varmint hunters are loath to do.
Vs. Other Varminters
Twenty-caliber cartridges might have a few things going for them, but why is the .204 Ruger the best?
Here’s the argument. Much like the .257 Roberts is the Goldilocks of whitetail cartridges, the .204 Ruger balances all the features you want in a varmint cartridge without going too overboard in any direction.
To make this case, we’ll compare the .204 Ruger to some of the cartridges designed for varmint hunting. The .22 Hornet, for example, pushes 35-grain bullets about 3,000 feet-per-second (fps). The Hornet pioneered the high-velocity smallbore category, but it can’t keep up with the .204 Ruger, which can launch a 32-grain bullet over 4,000 fps.
That added velocity allows the bullet to fly much flatter. In the Ruger vs. Hornet example linked above, the .204 Ruger drops a mere six inches at 300 yards with a 100-yard zero. The Hornet, on the other hand, drops over four times as far–28 inches.
Of course, the Hornet isn’t the only varmint cartridge out there. Arguably, the kings of the varminting world are the .22-250 Remington and the .220 Swift. There is no doubt that these cartridges deliver more energy, terminal velocity, and long-range capability than the .204 Ruger. The Swift (when you can find it) usually comes loaded with bullets 45 to 50 grains, which it fires around 4,000 fps. The .22-250 is most commonly loaded with 50- or 55-grain bullets, which it launches at something around 3,800 fps.
What does this mean? Both cartridges rival the trajectory of the .204 Ruger, but they deliver more energy downrange. At 300 yards, a 55-grain .22-250 loaded with a Hornady V-Max bullet has dropped about eight inches but is still carrying 766 foot-pounds (ft.-lbs.) of energy. A 32-grain .204 Ruger has dropped about three inches less, but it’s only delivering 479 ft.-lbs. of energy.
When it comes to varmint hunting, however, that’s not the end of the story. You don’t need more than 479 ft.-lbs. of bullet energy to dispatch a varmint (you don’t even need that much, actually), and most varmint hunters would prefer a flatter shooter to a piledriver.
What’s more, the .204 Ruger delivers less recoil than those super-charged .22-caliber options. This allows hunters to see the impact of the bullet without being jostled away from the eye box of a scope. While a suppressor or muzzle brake could achieve that result with a hotter cartridge, most hunters who use the .204 Ruger say those devices aren’t necessary.
And, to channel the late Bob Barker, that’s not all! While hotrod small-caliber cartridges are infamous for being hard on barrels, the .204 Ruger is not.
“Remarkably, it also offers excellent barrel life,” Frank C. Barnes notes in “Cartridges of the World.” “After shooting approximately 500 prairie dogs with the Ruger and Dakota rifles chambered for the .204 Ruger, a former contributing editor to this book found it to be an accurate, low-recoil round, superbly suited for long-range varminting.”
Last Shot
The .204 Ruger isn’t as powerful as other 22-caliber varminters, and it may cause more hide damage than the truly minuscule .17 Hornet. But it offers plenty of power to take varmints at most varmint-hunting ranges, and it can do it while delivering minimal recoil. That balance makes it a wonderful varmint hunter–perhaps the best on the market.
Unfortunately, there’s a reason that, as the title of this article suggests, you may have never heard of it. It’s not as uncommon as other cartridges we’ve highlighted, some of which can’t be found from any ammo company. But you’re unlikely to find it at your local gun shop, and many ammo companies don’t load it at all.
Midway USA, one of the biggest online ammunition dealers, lists only 16 options, ten of which are available as of May 2024. Hornady still produces several options, as does Nosler, and Federal, Winchester, and Remington offer one or two. Prices are reasonable at about $30 for a box of 20, and the most expensive is only about $2 per round.
The good news is that Savage, Ruger, Kimber, Mossberg, and CVA all chamber rifles in the tiny .204. If you spy one the next time you’re wandering the gun aisle, don’t hesitate to pick one up. Whether you like to chase coyotes, coons, prairie dogs, or bobcats, it’ll serve you well.
