A Complete Guide to the Hardest-hitting .25 Caliber Firearms (2023)

So the .25 caliber is only good for shooting rats at close range, right? Jonathan Young disagrees..

Responding to an Airgun Answers query about .25 for a recent issue, I revealed some old turnips about this caliber in traditional under 12 foot-pound form. Most of the rhetoric comes from people who tried it for just one session with a particular gun and pellet type and then walked away disappointed.

The .25 has been around since airgun shooting began in Britain, well before the First World War. But the new target club for the working class boosted the popularity of the cheap and fast .177 caliber, and the .22 cal slowly gained popularity while the big .25 hissed quietly in the background.

Hunting opportunities were few and far between in the class society of the time. Things picked up again after World War II and although I'm generalizing here, in the 1970's people were engaged in target shooting or hunting. For those who dared to do both, furs and feathers were talked about all over the country, and it was said that which caliber was good only for the particular type of quarry. That argument cost a lot of soggy cookies in the clubhouses. Then, like from another universe, the .20 came along to shake it up even more. But the reality is that with a little preparation and practice, you can shoot effectively with what you already have.

In the 1980s, the .25 caliber (6.35 mm) experienced a veritable comeback. With hunting firmly on the agenda, airgun manufacturers quickly caught on, as did pellet manufacturers. Many .25 airguns under 12 ft-lbs and a few air pistols under 6 ft-lbs turned up, along with a small supply of large shot.

No two guns perform the same, and testing is a must to get the best shot/gun combo in each caliber. Ignoring this is the root cause of claims that .25 is too big, too slow, or not worth trying unless you're at the FAC level. Sure, .25 would be impressive at 35 foot-pounds, but it would also be incredibly expensive. The oft-repeated wisdom about .25 is that it's only good for close encounters and is best used on rats up to 50 feet away. In fact, you can counter all of this by using lighter pellets and practicing your stalking technique.

So if we ignore the small talk and go out and buy our .25 because we're not easily led by others, what then? If the .25's greatest advantage is its stopping power, its greatest disadvantage in many people's minds is its steep trajectory. That the larger nugget flies slower than a tiny .177 isn't surprising since it obeys the laws of physics. Some people even believe that the quarry will escape before the pellet falls. But all species are most alert outdoors, and even a loud hammer on a PCP can cause them to flee.

Unlike the flatter shooting .177, the .25 is felt by some to be too far-fetched, but that goes for all calibers. We live on a round planet with gravity, so everything from buckshot to a soccer ball to an artillery shell has an arcuate trajectory. That doesn't stop the army from hitting things miles away. You just aim a little higher. Someone once told me that shooting a rabbit with a .25 would be like throwing pork pie at it. I didn't have a quick answer to that, it wrinkled me so much I couldn't stop laughing. But if you ask any rabbit who's been hit by a 20-grain .25 caliber bullet how it feels, you won't get an answer from them either.

What's the answer? Know your crosshairs. Any zeroing or impromptu point-and-shoot session on a club bench where you are shooting at a known distance will hide or mask the effects of ballistics and gravity. However, if you use a heavier bullet at different distances, the differences are more dramatic and require a little more thought with each shot. This is as true for shooting heavy .22 rounds as it is for shooting .25 in a pistol under 12 foot-pounds. Knowing where to aim, combined with impeccable range estimation, will pay off. Once you've done some basic homework to figure out how your particular .25 rifle and shot combination performs, the rest should be relatively easy.

Air pistol basics are easy to forget, so it's important to get your rifle checked out quickly. Loose bearing attachments on the springs can affect accuracy at any gauge. The triggers of any type of airgun must be adjusted to your preference; Just work with your weapon, you don't have to fight it. Check open scopes or telescopic sights and their mounts. Something tightened over a year ago, or even after a few doses of pellets, should be checked to make sure it's tight.

Keg cleaning isn't for everyone, but at some point it will be necessary. Some shooters even recommend cleaning between pellet types because manufacturers use different lead alloys. This is why some granules appear dark gray while others are glossy and shiny.

Make your choice

The choice of ammunition has priority. The airgun market was geared toward PCP, which (along with CO₂) love heavier shells. But many extremely heavy shots are too much for serious use under 12 foot-lbs and of little use to feathers that thrive on lighter shot. Fewer lighter .25 buckshots are available, but there's still plenty for comparison testing.

Brands like JSB and H&N are well known. The latter's Field Target Trophy is a personal favorite at nearly 20 grains. It was feared that the lighter Milbro Rhino had died but SMK confirmed they are now marketing them again, still available in the original green can with the famous little head and the newer yellow can in true 6.35mm. BSA Pylarm and .25 Marksman are lightweight favorites of yesteryear, and some very lightweight lead-free pellets have appeared recently, including the sub-15 grit Gamo PBA Platinum and the sub-17 grit Predator GTO, which further up the weight to reduce. Full spectrum from easy to medium to hard to buy and try will go a long way no matter what you use.

So once you've put together a selection of pellets, what's next? Emptying a can onto a kitchen towel will reveal how clean, dirty or damaged it is. Loose fragments of lead can remain from the manufacturing process, regardless of brand or price. An old kitchen strainer can be used to shake out the chips, and washing the pellets is easy at this stage. Today this may no longer be considered necessary, but it used to be the norm for any caliber. At 0.25 to under 12 ft-lbs, any preparation will help.

After drying, a pellet sizer can be used on each pellet. Many consider this unnecessary. This can be the case with some bolt-action pistols where the bolt actually meters the bullet for the caliber. The rim is the thinnest part of the pellet and the damage has little to do with the quality of the product or its manufacturer. Mass has to be lost somewhere to reduce weight, so the lighter pellets often have their skirts damaged. There are claims that the airflow at the moment of triggering is enough to change the size of irregularities in the shot, but how do you really know that? A caliper is a simple conical tube of a specific diameter into which the pellet is dropped and then pushed. Rather than just being used for repair, all pellets can be reclassified to a consistent standard.

In addition to repairing shot, the gauge is a valuable tuning tool. Note that even with an undamaged shot, the apron can cause too much drag. This slows the pellet as it travels up the barrel, wasting valuable kinetic energy. A gauge made specifically for your barrel can reduce drag while still allowing the shot to rotate through the rifling. Too small in size and you don't get any added value; too much and you will end up with less than optimal propulsion.

Sometimes the pellets are too solid in a given run. While the can may say 6.35mm and the barrel may say 6.35mm, that doesn't always mean they match exactly. Many German pellets are a very tight fit in the barrels of classic BSA pistols, for example it is widely recommended that these barrels were made slightly smaller for a time, say .243" rather than a true .25". Abarrel can even be large. By lining up a row of pellets on a hard surface and pressing very gently, the pellet's skirt will expand without deforming the head. When used unmodified, they either lack shot-to-shot consistency and the usual drag mentioned above, or they can be scaled down uniformly for that particular weapon. An old GEM rifle, for example, can really come to life with a modern shot, even if the barrel is closer to 6.50mm.

Any good hobby engineer can make gauges to order, but with so few available off the shelf, the TR Robb Adjustable Gauge deserves a mention. Here the tapered tube has an adjustable rod and can be preset to any depth, allowing for many variations in pellet size. By counting the setting turns on a few test pellets and then clicking in, a full can can be brewed quickly.

Another item worth mentioning is a pellet barrel spring insertion tool. After loading a pellet, this tool, which is usually a machined and polished piece of brass or plastic, is used to press the pellet's jacket to fit the barrel. This fit isn't a gauge, but it makes the skirt of every shot identical in situ, so you can expect greater consistency from shot to shot.

Next on the agenda is granular lubrication, once a hot topic that has now died down. The lubricant is intended to reduce the resistance of the pellets, a few drops or spray from the pump is enough to lubricate an entire can. There are several brands, while some people even make their own using different oils. Without this prep work, we would sometimes be shooting oversized shot, sometimes dirty, sometimes dry or dirty barrels. With clean, lubricated, and uniformly sized pellets, we increase the percentage of smaller cluster sizes in the target area.

It is helpful to weigh and time the pellets at some point in the process. Although we need to know that we are working legally, it is always interesting to know what is the difference between the different types of pellets.

However, in this testing phase, don't be surprised if the best bull's-eye returns lower readings than others on the chronograph. The difference between 9.5 ft-lbs and 11.5 ft-lbs is of little consequence to a rabbit, so after ensuring legality, accuracy of aim is more important than maximum output.

Each test session will now show which pellet group is the best. Remember some basics like holding when using feathers. Also, since the tests tend to take place over a long period of time, you should try to maintain a constant room temperature for the CO₂and sweet spot inflation pressures for PCP. Some BBs glow while others look hideous, but never discard BBs as trash - they may work better with another weapon. Prepare for surprises, too: this cheap gray lump might work better than the shiny thing that costs several pounds more. Cleaning a barrel between types of pellets is up to the tester. Grouping is more important here than hitting the target. If everything is in order, then this gun and its barrel are very forgiving. If some are completely blown out, and it wasn't caused by crosswinds, it's clear that gun and barrel don't like that particular bullet.

Now, with relatively little effort, you'll end up with a single shot, or maybe even an entire pickaxe, that you're absolutely convinced will work well in your .25. And that means you're ready to have some airgun fun.