The chart above shows the muzzle velocities that are required by different weight pellets to achieve a muzzle energy of 10.4 ft/lbs.

The best caliber Air Gun for you depends almost entirely on the intended use your air rifle or pistol and less so on how much you want to spend because there are some very good values in both rifles and pistols in the heavier calibers.

The greatest majority of air guns sold worldwide are.177 caliber. This caliber is the best for target shooting with either a rifle or a pistol for a couple reasons. One reason is that.177 caliber ammunition or pellets are lighter weight than the heavier calibers and require less energy to propel them on a flat trajectory at the usual target shooting distance of 10 m. That means that.177 caliber Air Guns can be constructed lighter and smaller which usually means less cost to the manufacturer and to you.

Even if you are not interested in the technical aspects the.177 caliber is often the best choice because of the wide variety of rifle and pistol choices from several different manufacturers. For well under $100 you can get a CO2 powered multishot repeater with a hardwood stock in some cases that shoots fast enough for a flat trajectory yet is still slow enough to stay reasonably safe in a backyard range setting.

Perhaps the best general purpose caliber for an Air Gun is.20 caliber. The trajectory of a.20 pellet is nearly as flat as a.177 pellet at the same muzzle velocity but its heavier weight carries about 40% more energy. The size and weight of a.20 caliber rifle is also not much different than the smaller caliber.177 caliber. This is probably the minimum size you should consider for hunting. Unfortunately the number of choices of.20 caliber air rifles is fairly limited.

If you intend to own only one hunting Air Gun then it should probably be a.22 caliber. Although the range of a.22 caliber pellet is less than the.20 caliber pellet the.22 pellet packs about 80% more downrange energy than a.177 caliber pellet. This is also a popular caliber size and you will find a good assortment of air rifles and a few pistols at different price levels. The best hunting air rifle bargain may be the Crosman 2260, a single shots, bolt action CO2 powered,.22 caliber air rifle.

Although there are some larger big bore air rifles available the.25 caliber is unbeatable in carrying the most downrange energy and knock-down force. The.25 caliber air rifle is commonly used in Texas to hunt wild pigs with wide success. For the most part.25 caliber hunting air rifles will be in the $300 and up range.

One of the best things about air guns is that their initial cost is a fraction of the cost of a conventional firearm. Operating costs can be measured in pennies especially in the.177 caliber category. You probably will not have do limit yourself to one or even two air guns.