The technology in adult air guns is all about how much you want to spend, and how much power you need.
The most common ones are single stroke spring powered guns(when you cock the barrel it compresses a spring that when the trigger is pulled it drives a piston forward to compress the air behind the pellet)
The new kid on the block is a gp, or gas piston kind of like the nitrogen piston that holds up the hood on your car or the hatch back on the minivan. It does the same job as the spring (compresses an air column when the trigger is released) but, it can stay cocked without degrading the power (a spring gun will weaken in power if the spring stays compressed over long periods of time)
And it does not suffer from the vibration as much as the spring guns.
But, they are hold sensitive, and some real gun shooters have a hard time adjusting to the artillery hold as it is called.
You hold the rifle loosely, and let it move in its own way when the trigger is pulled.
If you hold it firmly like a real gun, your accuracy with the spring/nitrogen piston guns will go out the window..
Also with these guns, use special airgun scopes, the double recoil (frontal and rearward)WILL break the best real gun scopes(who wants to trash their Nikon right?)
That brings us to the next ones, PCP (pre charged pneumatic) guns, they have a tank that is built into the gun that holds about 3000 psi of compressed air, it can be refilled with a scuba tank, or with a device similar to a bicycle pump (but it takes a lot of pumping to keep the air pressure up)
They are not hold sensitive like the spring/nitro piston guns , and have little to no recoil .
Then there is the co2, the small 12 gram cylinders we are used to only offer about 40 - 60 useable consistent shots before the velocity falls off. Unless they use the larger co2 bottles like a paintball gun uses.
Then there is still the old benjamin, and Sheridan style pump guns, they are still being made, and are still made out of brass.
They offer no recoil, no co2, and no special scopes needed.
Last forever.
And can be had for less than $150 or so.
And the power can be regulated by the number of pumps, 2 to sting the neighbors dog in the butt, 7 or 8 pumps to kill the raccoon raiding the garden..
The PCP guns can be had from about $300 up to $1500 or more
The single stroke guns are among the most powerful, and can be the least expensive of the guns running from $30 for a 800fps Chinese gun to $300 or so for a good suppressed .22 caliber nitro piston gun turning 1300fps with PBA ammo.
Yes it is legal for them to suppress a air gun with no federal tax stamp like what is needed for a real firearm suppressor..
Hope this answered a few questions.
This is a new (January 2013) production Benjamin .22 pump up.
With the finish removed..
And Williams sight added.
Cost me $100 shipped to my door..
