What is the right power level?
The level of power that can be generated with airguns depends on what type of airgun you’re talking about. Most of the inexpensive CO2 and pneumatics that are produced for the mass market plinkers generate from 4 to 10 fpe, while some of the the big bores can generate over 600 fpe!
As a general rule of thumb, even the most high powered springers and PCP production guns are much less powerful than a .22 rimfire. While most CO2 airguns are fairly low powered by comparison to springers and PCPs there are some CO2 guns doing 15 fpe out of the box, but these are the exception. Springers usually generate around 16 – 20 fpe, though there are some very powerful models in .25 caliber that gets up to 30 fpe. Many production pre-charged pneumatics can generate much higher energy levels, the little Brocock specialist gets over 20 fpe and the Daystate Wolverine and FX Boss .303’s get up to around the 100 fpe mark. The FX Verminator, which offers adjustable power, allows the shooter to dial it down for plinking or target shooting in the basement range, crank it up a bit for pest control around a barn where you don’t want to risk over penetration or punching a whole through the roof with a miss, then go full power when heading out for raccoons or prairie dogs at a greater distance. This effectively gives you three guns for three applications for the price of one.
You can also change the power in your pneumatic guns by fiddling with the hammer springs; a lighter spring will reduce the power and a heavier spring will increase it. In my DAQ .308 I use a light spring when shooting the light round ball for small and medium game, but switch over to a heavier spring when using a 120 grain cast bullet for bigger game. The tradeoff you make is that the shot count is reduced, with the heavy spring I get about four full power shots and with the lighter spring it jumps up to seven or eight shots.
What gun to use for what game is an interesting topic that is sure to get airgunners arguing, or at lest talking! My personal belief is that any .177 or .22 airgun that generates 12 fpe is appropriate for small game animals at 30 yards. If you’re going to push the distance another 10 yards I’d want something in the 14 to 16 fpe range. You have to remember that the energy level when your pellet finds its quarry will be lower than it was at the muzzle, and that the power diminishes more rapidly with smaller and lighter pellets. Some shooters that use their airguns for pest control in more built up areas, will opt for lower power 8-9 fpe guns because they shoot at closer range around barns and animal feed lots for instance, and want to make sure that they don’t damage animals or property with a missed or over penetrated shot. When you start to get up into what I consider medium sized airgun quarry such as raccoon or woodchucks I prefer a .22 or .25 putting out around 30 fpe. If I am going to shoot at longer distances for medium game, I will often use one of my larger bore airguns. When moving into the area of larger or harder to kill game, say coyote or bobcats I think a .308 caliber in the 100 fpe range is a good idea. And if the quarry is large and tough: deer, wild hogs, exotics, or African plains game, I think a large bore airgun that puts out at least a couple hundred FPE is the minimum, and I prefer a gun in the 300 fpe on up category. There is no doubt that you can kill an animal with a lower power gun than I’ve recommended, it has been done. That doesn’t make it a good idea, many deer have been killed with a .22 rimfire, but there is a reason it is not legal in most places, the chances of wounding or maiming an animal is high.
What’s this 12 fpe thing in the UK?
It is somewhat ironic that in the United Kingdom, which is arguably the center of the airgunning universe and where many of the best PCP airguns originate, there is a limitation on the power of an airgun that can be owned without a fire arms certificate (FAC). Air rifles can not be over 12 fpe and air pistols can not be over 6 fpe. If a gun exceeds this limit and the person in possession of that gun does not have an FAC, heavy penalties up to big fines and a long prison sentences can result. This limit does allow enough power for small game hunting out to about thirty yards or so, but does not allow much margin of error. I believe this is one of the reasons that British airgun hunters are such sticklers when it comes to restricting their shot placement to their quarries head.
The reason that this limit was established in the first place seems to be a result of lobbying initiated from within the airgun manufacturing industry itself. The story goes, that at the time this regulation was passed the British airgun manufacturers were unable to produce guns that generated the power level of foreign imports. The tactic was to protect the market by enacting this arbitrary limit and provide a shield against technologically advanced offshore competition. Unfortunately once this type of restriction is in place the chances of having it repealed, especially in the current anti shooting climate, are slight. Some swear by this story while other say it is urban legend, but I’ve not heard any better explanation and the unfortunate bottom line is the limit exists. While it is eminently possible to hunt at 12 fpe, my personal preference is to have at least 16 fpe as I have seen a pretty significant difference in the ability to achieve clean kills with just this 4 fpe jump. From a practical standpoint, if you buy a gun from Britain make sure it is or can be tuned up.
Too Much Power?
My personal opinion is that unless there is a good reason to limit power, say that you’ll be shooting around equipment or livestock, more power is better as long as it doesn’t adversely impact accuracy. But as has been said, only accurate guns are interesting, so I think you always have to frame up the answer in this context. I think we’re luck in the USA in that we don’t have power restrictions, and one of the reasons is that it gives us the freedom to push the limits of air power ballistics. But if we had the same type of limits as the UK, it might change my hunting style somewhat, but I’d keep going and keep being an effective hunter.