The following post is intended as a detailed general guide to categories of air guns and how they function to help those who are curious but know next to nothing. This post covers the many conversations I’ve had with powder-burning acquaintances at my club who marvel in disbelief at the capabilities of my airguns and who then ask lots of questions. These are the answers I give. This is merely an addition to the many, “getting started” air gunning articles, posts and videos out there. My intention is to be more comprehensive than many of the sources I scoured when researching my entry into this hobby some years ago. If you like detail and slightly deeper explanations, perhaps this is the post for you.
Let’s start with the powerplant categories: PCPs; Spring/Gas Ram “Springers; Multi-pump pneumatic; and hybrid PCPs
Let’s start with the powerplant categories: PCPs; Spring/Gas Ram “Springers; Multi-pump pneumatic; and hybrid PCPs
- PCP (Pre-charged pneumatic). This broad category includes the platinum standards for competitive bench rest, field target, Olympic airgunning, as well as plinking and hunting for things great and small. In short, this is an incredibly diverse and capable category.
- PCPs come in calibers from .177 to over .50.
- They range in power from sub 12 ft. lbs. to over 1000 ft. lbs.
- They can be single load, magazine-fed repeaters, or semi-auto (less common).
- They can be pistols, rifles or bullpups.
- They can cost from a few hundred to many thousands of dollars.
- They are frequently highly adjustable, meaning changes can be made to tune the gun for varying powers and velocities.
- For refills, they REQUIRE A SOURCE OF COMPRESSED AIR which can be supplied by devices ranging from specialized hand pumps to compressors filling storage bottles such as SCBA tanks. This extra infrastructure causes some people to shy away from even considering these guns. (Sadly, they’ll never know what they are missing)
- The most common operating pressures range from 3000 psi to 1000 psi with some guns handling up to 4500 psi. Compare this to 80 to 120 psi for a common shop compressor (which cannot be used alone to fill an airgun). This extremely high pressure means PCPs need to be handled with care and should be discharged/empty before users attempt to disassemble or repair them.
- In simplest terms, PCP’s store a supply of highly-compressed air in an on-board tube or tank.
- They use that supply of air to propel pellets without the need to pump or cock a piston between shots.
- It’s common for PCPs to get 30, 50 or even 100 shots between fill ups. That number can go much higher or be very limited depending on variables like air capacity, caliber, power and valve efficiency.
- The guns shoot when a burst of high-pressure air is released from a tiny valve. Typically, this is achieved when the trigger releases a spring-powered hammer that falls on a pin that pops the valve open for a millisecond. Conceptually, this mechanism is similar to the hammer and firing pin in firearms, except that the pin opens a valve rather than striking a primer.
- Models can come either unregulated, or with a regulator. Over a series of shots, velocities can change in unregulated guns as the air in the tank slowly discharges and decreases in pressure. Regulators keep the power steady and predictable over a series of shots, generally improving accuracy at longer ranges.
- PCPs are generally required for shooting with precision beyond 50 yds with some people pushing boundaries into the hundreds of yards.
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- Spring piston or gas ram piston (“Springers”). After being cocked by the user, these guns operate when a large piston driven by a powerful spring or gas ram is unleashed inside a chamber. The resulting compressed air then blasts through a small port to propel a pellet down the barrel.
- Springers are generally less powerful and less accurate than PCPs.
- The most obvious advantage over PCPs is that there’s no need for special infrastructure to fill the gun with air.
- An additional advantage over unregulated PCPs is that springers shoot at a more consistent velocity every time because there is no tank that is declining in pressure through a string of shots.
- One disadvantage is that the violent action of the piston creates significant recoil before the pellet has even left the barrel, making accurate shooting at greater distances a challenge.
- Due to the powerful piston, recoil occurs in 2-directions which can destroy even high-end scopes not designed for double recoil. (Centerfire shooters are frequently stunned to learn a $99 .177 magnum pellet gun from Walmart can damage scopes that would be fine on a .308 powder burner) It is important to use “airgun rated” scopes on springers.
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- Springers are generally single shot and pellets are loaded into the breech by hand. However, some models are fed by unique magazine mechanisms.
- Springers range from $59 Walmart break-barrels to competition rifles going for thousands of dollars.
- These guns can achieve impressive accuracy but managing recoil is the name of the game. The more POWERFUL the gun, the harder it is to shoot straight. Generally, a lighter “artillery hold” that allows the gun to recoil naturally and repeatably in the shooters hands is preferable to a firm firearms-style hold. (You can’t “force” a springer to shoot straight).
- Generally used 60 yards and under.
- Competition guns are usually 12 ft. lbs in power or less. Hunting guns or “magnum” springers run to about 20 ft. lbs in power, with a few models going over 30 ft. lbs. (with frequently disappointing accuracy results).
- The most accurate springers are generally lower in power, and have a fixed barrel. Cocking in these fixed barrel guns is achieved through separate underlever or sidelever actions.
- Springers can be pistols or rifles.
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- CO2 airguns: Operated by compressed CO2, these fun pistols and rifles are generally low power, and do not maintain consistent velocity as the CO2 is discharged, making accuracy over a gas charge a serious problem at any significant range. They can be affected by temperature. With some notable target model exceptions, CO2 is generally relegated to “fun guns”, plinkers and replicas. Due to low and variable power, hunting with a CO2 gun should be a crime in places where it is not already.
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- Multi-pump pneumatic: These are pumped up by the user for each shot. Generally, the user will need 3 to 8 strokes per shot. These guns are generally not as powerful or capable as PCPs. Multi-pumpers can be more accurate than many springers because there is no piston recoil. These guns have their fans, but because of the need to stop and pump multiple times per shot, and the lower power compared to PCPs, interest in them has been in decline for some time.
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- Hybrid-PCPs: This is a small but interesting category of guns that combines the on-board compressed air storage of a PCP with a lever or pump that allows the user to “top off” the gun after a short series of shots. Preppers and survivalists have a particular interest in these guns, as do PCP fans who don’t want to drag tanks, pumps and compressors all over kingdom come. This category remains limited, however.
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Here are some Airgunning Basics:
- Pellets are not bullets and therefore “velocity” is not always your friend.
- Lots of new airgunners are focused on power and speed. Lots of airguns are marketed as “1100 fps!” This is all wrong.
- Pellets are stabilized in flight by a skirt and become unstable and inaccurate as they approach and break the speed of sound. Most pellets do best in the accuracy department between 850 and 910 fps or less.
- Therefore, if you are into accuracy you need to tune it down. If you are into power (as in killing stuff) you need to go to a bigger caliber with a heavier projectile – not an increase in velocity. You can’t kill what you can’t hit.
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- The caveat to this is slugs. Airgunners who want to amp it up can shoot slugs, particularly in larger calibers. However, many airgun barrels are not compatible either because of twist rate or choke. Thus, slug liner systems and specific slug barrels are all the rage. Predictably, this can get very expensive.
- A second caveat is that all guns do not shoot all pellets well. One guy can shoot one brand sub moa, while another guy gets a shotgun pattern with the same pellet in a different gun – and vice versa. This is true voodoo. No one seems to have a decent explanation for any of it. New owners do a lot of pellet testing and comparisons to find the food his or her gun “likes”.
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- If you want a flat shooting gun for ACCURACY 50 yards and in, you may want to be looking at .177 cal. target rifles. If you want power for killing stuff or need larger projectiles that can buck the wind at longer range, you’ll want to be thinking .25 caliber and up, but you’ll get a real arc in your trajectory and lots of windage effects. This is part of the fun of the game. Out to longer ranges (60 and beyond) you many find yourself calculating ballistics that would make a Marine sniper’s head spin. Powder burners need hundreds of yards to get the same challenge.
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- Tuning: Much is made about “tuning” airguns, and for good reason. At intermediate and advanced levels in PCPs, you may want to manipulate velocity to achieve either better accuracy, power, or number of shots per fill (efficiency). This can be done through lots of adjustments affecting how deeply the valve is popped open and for how long. Tinkering possibilities range from hammer spring tension to hammer weight to length of hammer travel to adjusting the regulated pressure (in guns equipped with a regulator). In Springers, tuners manipulate the length and strength of the spring, adding or changing spring guides in the chamber, as well as polishing and lubricating the compression chamber to achieve better smoothness and power. The combination of adjustments in both types of guns can seem like voodoo and some people prefer to send guns away to professionals for maintenance and tuning, though most people with some basic mechanical ability and tools can figure it out. Think of it this way: Where a powder-burner may be manipulating loads, an airgunner is manipulating his gun. Entire books have been written on tuning. It’s a Zen thing.
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- Maintenance and overhauling:
- Because of valving, PCPs are much more complex than firearms. They are filled with O-rings, seals, valves etc. This stuff eventually leaks over time. Generally, it’s no big deal to tear one down and take care of issues – depending on your comfort with tools and mechanics. Like any gun nut, people LOVE to modify PCPs with special valves, hammers, springs etc. However, mishandling a gun with air on board can result in an explosion or failure. Safety is an issue.
- Springers are simpler, but owners of a quality gun that will live for generations need to be prepared for eventual tear downs to replace worn seals and such over time. “Tuning” a springer often involves tinkering with the spring (or changing it to a custom model) along with any number of potential modifications. Special tools (like a rifle-sized spring compressor) can be required depending on the model
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- The “Shot String” in unregulated PCPs: Much of the unregulated PCP airgunning game is focused on a consistent and predictable shot string and the tuning to achieve it. This is the count of usable shots you get from a fill up. Some guns start at a high velocity which declines each shot as the tank discharges. This generally indicates the gun has an overpowered tune and you are wasting both air and time (since you can’t maintain accuracy shot to shot as the velocity declines). The preferred outcome is an arc which begins at a slightly lower velocity, climbing modestly to a peak speed, and then falling off slightly again. (For instance, 870 fps up to 890 fps and back down to 870 over 30 shots.) Most gunners are looking for a “sweet spot” in that arc where the velocity levels off for about 15 shots near the peak with very little variation in velocity (5fps-10 fps over 15 shots). This is where you’ll be the most accurate at longer ranges.
- The arc happens because at the beginning, the hammer has trouble fully opening the valve due to the higher pressure of the full air tank behind it. (resulting in slightly lower velocity). As the pressure declines, the valve can open more (increasing velocity) – until the pressure in the tank itself begins to decline (lowering velocity again).
- If you have a regulator in your PCP gun, this generally negates the whole “arc” thing because the regulator delivers the same pressure to the valve regardless of the pressure in the tank -- until the tank falls below the regulated pressure. Then velocity falls off dramatically and you need to refill.
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- Pumps and compressors. If you have a PCP, you need a way to fill it up.
- Hand pumps: Generally, guns that operate on pressures of up to 3000 psi and have small to modest sized tanks can be filled and topped off with a hand pump. These guns from .177 to .25 caliber, will deliver 25 to 40 usable shots and run from 12 ft. lbs to over 40ft. lbs of energy before needing to be topped off, depending on caliber and tune. A top off means 50 to 80 strong strokes with the pump, which can take a few minutes and cause one to break a sweat. Warning: do not go cheap on a hand pump. Expect to pay $150 to $225 or more. The o-rings and seals in cheap pumps fail quickly and rebuild kits are hard to find. It’s best to go with a quality pump that you know you can rebuild when the time comes. Lubrication is important for obvious reasons. Newbies almost always start with a hand pump. It works fine, but … If they get hooked on shooting, like I did – they eventually get tired of it and save up some money for….
- Compressors and tanks: There are inexpensive Chinese single piston compressors such as the Yong Heng out there for about $225 or less. They are hit or miss on quality. For instance, I got a turkey that burned up and seized a piston. Others report great results. It all has to do with how hard you use it AND HOW METICULOUS YOU ARE ABOUT LUBRICATING AND COOLING IT (they are water cooled). If you have a compressor, it’s unlikely you’ll want to haul it to the range with you. That means you’ll need a 3000+++ PSI capable tank to store and carry air.
- Warning on SCUBA “dive tank” set ups. It all sounds great until you find out that most dive shops won’t fill to even 3000 ps You’ll end up disappointed if you have a gun that wants to be filled to 3000 psi or above (most models). With SCUBA, your first fill if you’re lucky, will bring your gun to 2900, and it will go down from there. This makes the whole set up unsatisfying as your refill pressures decline. On a lower pressure gun such as the Benjamin Discovery, which fills to 2000, the SCUBA is a more viable option.
- Warning: Old firehouse tanks. There are tons of retired 4500 psi SCBA firefighting breathing bottles for sale on EBay and other sites. They can be really cheap until you realize the price increases with the years of service left on the DOT sticker. Reputable re-fillers will NOT fill a bottle with an expired DOT sticker, and you’ll be out of luck. If you feel like buying your own compressor and taking a chance on filling to 4500 psi an expired tank, or a no-name from China, you can save a lot of money. The risk associated with this strategy is the source of endless commentaries on airgun blogs. I’ve never heard of someone being killed by an exploding tank, but I figure we have DOT regs for a reason.
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- A note on $$$$$$: This is expensive up front, BUT low cost for a lifetime because you’re not buying powder-burner ammo at $.20 per round or more. If you like to shoot A LOT for accuracy and fun, this is a great way to go because pellets are cheap. Inversely, firearms are generally less expensive up front, but every time you go to the range you are lighting fire to dollar bills – particularly if you are shooting semi-auto. As far as money is concerned you may pick your poison. None of it is free, but there is a good economic argument for airgunning.
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- A note on Hunting: Larger caliber airguns are powerful and can be used to bring down deer and even elk. Some airguns are modified to shoot arrows to kill big game! (very accurate BTW). On the other hand, most shooters in the .177 to .22 categories are gunning for small game and pest species such as squirrels, rabbits, feral pigeons, starlings and English house sparrows. While there is plenty of room for argument, I personally believe that .25 cal and up should be required for the groundhog, racoon, fox, and coyote category. You’ll find lots of blog posts and videos documenting people killing bigger things with smaller calibers. What they don’t show on the videos or brag about in print is the game that’s been lost or horribly wounded. I feel that ethical hunting means being mindful of the limitations of your gun. It all comes down to foot/pounds of energy and accuracy. I compare everything to .22LR, which shoots about 85-90 ft. lbs. A highly powered .177 would be making 20 ft. lbs. and most make far less. An average powered .25 generally makes 40 to 60 ft. lbs (higher with mods). .22 cals fall in the middle (around 30 ft. lbs.). From these numbers you can see that you are not even approaching the power of a .22 LR powder-burner. This means you MUST shoot accurately. On mammals, most ethical airgunners in smaller calibers are focused on clean head shots. Targeting the vitals also works, but it is frequently a bleed-out scenario rather than a quicker death by the pure shock of the impact. Larger calibers up to .50 are a growing and popular category. Some make upwards of 1000 ft. lbs. However the guns that make big power also eat air, and may only provide 3 to 5 shots per fill up. Projectiles in these generally are flying sub sonic at 750 to 900 feet per second (think .45 ACP or a black powder rifle). These big bore airguns are effective, but not the same as shooting game with a 30-06.
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- A note on modifications: There are exceptions to just about every one of the generalities I have outlined here thanks to modifications. Are there .25 cal air rifles that get 80 or 90 foot lbs? Yes, there are. This post merely lays out the general capabilities of commonly available guns “out of the box” in their various calibers and categories.
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- A note on modifications: There are exceptions to just about every one of the generalities I have outlined here thanks to modifications. Are there .25 cal air rifles that get 80 or 90 foot lbs? Yes, there are. This post merely lays out the general capabilities of commonly available guns “out of the box” in their various calibers and categories.
- A note on Hunting: Larger caliber airguns are powerful and can be used to bring down deer and even elk. Some airguns are modified to shoot arrows to kill big game! (very accurate BTW). On the other hand, most shooters in the .177 to .22 categories are gunning for small game and pest species such as squirrels, rabbits, feral pigeons, starlings and English house sparrows. While there is plenty of room for argument, I personally believe that .25 cal and up should be required for the groundhog, racoon, fox, and coyote category. You’ll find lots of blog posts and videos documenting people killing bigger things with smaller calibers. What they don’t show on the videos or brag about in print is the game that’s been lost or horribly wounded. I feel that ethical hunting means being mindful of the limitations of your gun. It all comes down to foot/pounds of energy and accuracy. I compare everything to .22LR, which shoots about 85-90 ft. lbs. A highly powered .177 would be making 20 ft. lbs. and most make far less. An average powered .25 generally makes 40 to 60 ft. lbs (higher with mods). .22 cals fall in the middle (around 30 ft. lbs.). From these numbers you can see that you are not even approaching the power of a .22 LR powder-burner. This means you MUST shoot accurately. On mammals, most ethical airgunners in smaller calibers are focused on clean head shots. Targeting the vitals also works, but it is frequently a bleed-out scenario rather than a quicker death by the pure shock of the impact. Larger calibers up to .50 are a growing and popular category. Some make upwards of 1000 ft. lbs. However the guns that make big power also eat air, and may only provide 3 to 5 shots per fill up. Projectiles in these generally are flying sub sonic at 750 to 900 feet per second (think .45 ACP or a black powder rifle). These big bore airguns are effective, but not the same as shooting game with a 30-06.
- A note on $$$$$$: This is expensive up front, BUT low cost for a lifetime because you’re not buying powder-burner ammo at $.20 per round or more. If you like to shoot A LOT for accuracy and fun, this is a great way to go because pellets are cheap. Inversely, firearms are generally less expensive up front, but every time you go to the range you are lighting fire to dollar bills – particularly if you are shooting semi-auto. As far as money is concerned you may pick your poison. None of it is free, but there is a good economic argument for airgunning.
- Pumps and compressors. If you have a PCP, you need a way to fill it up.
- The “Shot String” in unregulated PCPs: Much of the unregulated PCP airgunning game is focused on a consistent and predictable shot string and the tuning to achieve it. This is the count of usable shots you get from a fill up. Some guns start at a high velocity which declines each shot as the tank discharges. This generally indicates the gun has an overpowered tune and you are wasting both air and time (since you can’t maintain accuracy shot to shot as the velocity declines). The preferred outcome is an arc which begins at a slightly lower velocity, climbing modestly to a peak speed, and then falling off slightly again. (For instance, 870 fps up to 890 fps and back down to 870 over 30 shots.) Most gunners are looking for a “sweet spot” in that arc where the velocity levels off for about 15 shots near the peak with very little variation in velocity (5fps-10 fps over 15 shots). This is where you’ll be the most accurate at longer ranges.
- Maintenance and overhauling:
- Tuning: Much is made about “tuning” airguns, and for good reason. At intermediate and advanced levels in PCPs, you may want to manipulate velocity to achieve either better accuracy, power, or number of shots per fill (efficiency). This can be done through lots of adjustments affecting how deeply the valve is popped open and for how long. Tinkering possibilities range from hammer spring tension to hammer weight to length of hammer travel to adjusting the regulated pressure (in guns equipped with a regulator). In Springers, tuners manipulate the length and strength of the spring, adding or changing spring guides in the chamber, as well as polishing and lubricating the compression chamber to achieve better smoothness and power. The combination of adjustments in both types of guns can seem like voodoo and some people prefer to send guns away to professionals for maintenance and tuning, though most people with some basic mechanical ability and tools can figure it out. Think of it this way: Where a powder-burner may be manipulating loads, an airgunner is manipulating his gun. Entire books have been written on tuning. It’s a Zen thing.
- Therefore, if you are into accuracy you need to tune it down. If you are into power (as in killing stuff) you need to go to a bigger caliber with a heavier projectile – not an increase in velocity. You can’t kill what you can’t hit.
- Pellets are stabilized in flight by a skirt and become unstable and inaccurate as they approach and break the speed of sound. Most pellets do best in the accuracy department between 850 and 910 fps or less.
- Lots of new airgunners are focused on power and speed. Lots of airguns are marketed as “1100 fps!” This is all wrong.
- Pellets are not bullets and therefore “velocity” is not always your friend.
- Hybrid-PCPs: This is a small but interesting category of guns that combines the on-board compressed air storage of a PCP with a lever or pump that allows the user to “top off” the gun after a short series of shots. Preppers and survivalists have a particular interest in these guns, as do PCP fans who don’t want to drag tanks, pumps and compressors all over kingdom come. This category remains limited, however.
- Multi-pump pneumatic: These are pumped up by the user for each shot. Generally, the user will need 3 to 8 strokes per shot. These guns are generally not as powerful or capable as PCPs. Multi-pumpers can be more accurate than many springers because there is no piston recoil. These guns have their fans, but because of the need to stop and pump multiple times per shot, and the lower power compared to PCPs, interest in them has been in decline for some time.
- CO2 airguns: Operated by compressed CO2, these fun pistols and rifles are generally low power, and do not maintain consistent velocity as the CO2 is discharged, making accuracy over a gas charge a serious problem at any significant range. They can be affected by temperature. With some notable target model exceptions, CO2 is generally relegated to “fun guns”, plinkers and replicas. Due to low and variable power, hunting with a CO2 gun should be a crime in places where it is not already.
- Due to the powerful piston, recoil occurs in 2-directions which can destroy even high-end scopes not designed for double recoil. (Centerfire shooters are frequently stunned to learn a $99 .177 magnum pellet gun from Walmart can damage scopes that would be fine on a .308 powder burner) It is important to use “airgun rated” scopes on springers.
- Spring piston or gas ram piston (“Springers”). After being cocked by the user, these guns operate when a large piston driven by a powerful spring or gas ram is unleashed inside a chamber. The resulting compressed air then blasts through a small port to propel a pellet down the barrel.
