This is excerpted from an article I wrote for Airgunner Magazine in the UK a couple years back. I’ve found myself gravitating to the .30, and for many of the same reasons I drifted away from the .22 to the .25 a few years earlier. BTW: Airgunner is a great magazine available either as a hard copy or a digital download, and is a great shooting resource.
Because of the wide-open spaces found in much of the USA (from the Western deserts to the Midwestern plains), longer shots are often required. It is also fair to say that there is a broader selection of game available to hunt, some of which (even limiting the discussion to small game) can be quite a bit larger than that encountered in the UK. An American cottontail rabbit is about the same size as the rabbits on your side of the pond, and a crow is a crow, but a jackrabbit may weigh in at twelve pounds and the average adult turkey is around sixteen pounds. And with no limitation on caliber or power in most of the country, the .25 has become quite popular over the last few years, with a growing number of airgun hunters migrating to the quarter bore.
If you try to keep a .25 pellet under 12 fpe, the resultant trajectory is akin to tossing a brick down range with an underhand toss. This limits the utility of the caliber in legal limit guns, but get it blazing downrange at 900 fps and it’s quite a different story! If both a .22 and a .25 are propelled at the same velocity, the .25 caliber has a trajectory roughly equivalent to the .22, perhaps a bit flatter because it retains energy more efficiently as it travels further from the muzzle. Some will argue that the .25 is less influenced by wind, though I personally feel it’s a matter of degrees. This might be the case in light winds, but if the wind is howling I either move the shots in closer or put my rifle away until the weather moderates. There is undoubtedly a difference in terminal performance; the larger surface area of the .25 in conjunction with the higher energy delivered on impact can make a substantial difference in knockdown power, especially on body shots when compared to the .22.
If hunting prairie dogs, where the range may exceed 100 yards, the knowledge that a body shot will anchor the quarry makes it a viable shot placement and increases the effective kill zone substantially. To those that would argue that the joy of airgun hunting is getting up close and personal to one’s quarry, I agree. But I would also remind them that firearm hunters often shoot prairie dogs at 700 yards or more because they are so difficult to get close to, and in this context 75-100 yards is a fairly short range.
So, the .25 has gained popularity in the American market because it is efficient out of high powered PCP rifles, offering both a relatively flat trajectory and improved velocity retention. Furthermore, it offers excellent results on game because of the increased energy delivered on target, and the increased size of the wound channel created. This results in an effective longer range hunting tool for small game, but also allows larger game to be taken at closer ranges.
Now if you take the same set of factors into consideration, and apply them to a comparison of the .25 and .30 calibers, I believe the same results will be noted. If the .30 caliber pellet, which in the context of this discussion is limited to the conventional Diabolo pellet design, is propelled at 900 fpe the same results are noted; the trajectory is flat, velocity retention is improved, the larger surface area delivers greater energy on target and creates a larger wound channel than noted with the .25.
I don’t really need a .30 to hunt squirrels or most small game because I can invariably close the distance to my prey. But some smaller pest species such as prairie dogs, crows, and ground squirrels may require longer shots in some terrains. If a varmint with greater mass, such as a ground hog, raccoon, or nutria provides an opportunity for a shot, the same gun can be used with confidence. And for quarry of any size, the body shot becomes a much more attractive option as a result. The gist of this is that a hunter can buy a single rifle, and use it for a wider variety of game. In the areas where I hunt, there are more than twenty species that can be harvested with an Airgun, that range in weight from a half pound to twenty pounds. There is an advantage to one gun that can do it all well!
The biggest disadvantage of the .30 is that it will carry further than either a .22 or .25 propelled with the same muzzle velocity. Note that I am limiting this discussion to Diabolo style pellets, which have an intrinsically poor ballistic coefficient. The .30 pellet still sheds energy relatively quickly, when compared to even a standard .22 LR rimfire bullet. You might ask why not just use a .35 justifying it with the same arguments? The short answer is that it doesn’t fit the application. There is a point of diminishing returns; shooting a squirrel or rabbit with a .30 is not over the top, but a .35 is! It tends to carry too far, over penetrates, and will tear up small bodied game at close range. To my way of thinking the .35 is a better shared-service caliber bridging medium and bigger quarry, as opposed to the .30 for small to medium sized game.
Another disadvantage that has been cited in the past, is the limited availability of guns chambered in .30 caliber and difficulty in finding ammunition. However, in my gun room I currently have an Evanix Rainstorm, an Evanix Snipper, an FX Boss, a Daystate Wolverine, the Hatsan BT Carnivore, the Evanix Max Bullpup, the Hatsan Hercules, the MROD Velociraptor and the Ataman M2R Carbine all in .30 caliber. And there are more rifles coming to market! Obviously, when it comes to shooting platforms we are not starved for .30 caliber options! The rifles I’ve mentioned are designed to shoot standard pellets, and tend to generate around 70 – 95 fpe though some will do a bit more. A couple of these rifles can handle shorter lightweight cast bullets, and I have rifles in my collection that will exceed 200 fpe (such as my Quackenbush and Pro Big Bore .308’s). But this is accomplished with cast bullets using higher fill pressures, more air per shot, and a resulting reduction in shot count. I believe these comprise a different category of air rifle which address a completely different use case, and for this reason have excluded them from this discussion.
As far as pellets, there has been a limited selection, primarily the JSB Exacts and private label variations thereof. This does not trouble me greatly, because these pellets tend to work well in every .30 caliber rifle I have, and provide excellent terminal performance on game to boot! There are however, also new pellets coming to market; at the SHOT Show in Las Vegas last month both H&N and Hatsan had released new .30 caliber pellets, and the Predator Polymag pellets are now available in this caliber as well. Having made my case for the .30 caliber, I will now qualify my position. If I was living in a region where there were power restrictions in place, where there was not a need to reach out over longer distances, or if there was not legal game available that required more energy or a larger wound channel to ethically harvest, there is less reason to opt for this caliber. However, in those places where higher powered rifles are permitted, where there is no limitation on caliber, and there is either larger quarry or a need to reach out further, I would expect to see interest in the caliber grow. There may also be a small subset of target shooters that are interested in long range bench rest competition that might gravitate towards the caliber, but I would expect it to gain the most popularity with hunters. So, if you see companies promoting yet another caliber and ask yourself why?? I hope this provides some insight from a “foreign” shooters point of view!