Because new model air rifles and guns come out quite often it is impossible to say who is the most powerful. However the top end of rifles are the PCP model rifles. Various makers manufacture the "Precharged Pneumatic" Rifles. These Rifles exceed the C02 and Spring Rifles in power. The Rifle is charged with a Scuba tank. The Calibers can be found in .177, 20, 22, 25, 9mm, 45, and 50 Caliber.
Obviously these rifles are more expensive than their counterparts. Several models run into the Thousands of dollars.
If you want a powerful spring air rifle look at the "Banjman Super Streak." I am sure that there are others on the market so I would compare the different models for Speed (FPS) Feet per second and pellet size and weight. Several of the new spring rifles can fire a heavy pellet (Lots of knock down power) faster than 1000 FPS.
Pellet guns are more powerful. They are stronger because they use a CO2 Gas, whil BB guns are spring-powered.
Most pellet rifles are capable of killing a nutria. A few of the more powerful pistols can also kill a nutria. Do not use a BB gun. they are less accurate and may only injure the rodent.
If you are asking strictly about BB guns and not rifles, pellet guns or pellet rifles then I would have to say it most likely is the "IZH-Baikal Drozd BB Gun." It fires at a rate of 541 feet per second. It will fire 1, 3 or 6 shot burst at the pull of the trigger. However Pellet guns and Pellet Rifles are more powerful.
Your question is a little odd, because there are BB guns and rifles and there are Pellet guns and rifles. So if you asked "What is the most powerful air gun or rifle", then I could answer you. But you only asked "what is the most powerful BB gun." There is no single most powerful BB gun however the IZH Drozd BB Pistol fires a .177 BB at 541 ft/sec. And this is about as fast as you can get with a BB gun. Now a Pellet Gun/Rifle is a much different story. Pellet rifles have attained a speed of over 1,300 ft/sec with a .177 pellet. But that is speed NOT power! Pellets, unlike BB's come in different sizes from .177 up to 50 caliber. A 50 caliber pellet is about as large as your finger and puts a pellet downrange at around 680 ft/sec. It is much slower than a small .177 pellet but it is capable of bringing down a full size deer or bear. (I'm not kidding) These rifles will cost you around $600 and are in the PCP (PreCharged Pneumatic) Class of air guns / rifles. These are the most powerful airguns today (See the link below) Also when the page opens up watch the video on the left.
There are BB guns and there are Pellet guns. BB guns are not as powerful as pellet guns. BB gun can only fire a .175 caliber BB at a maximum of around 500 FPS. Pellet guns can fire a .177 pellet over 1200 FPS. The most powerful class of Pellet guns and Rifles are PCP's (PreCharged Pneumatic) air guns. These require a special pump or Scuba tank to charge them to 3000 PSI and can fire up to a 50 Caliber slug. Capable of bringing down a full size deer. Pellet guns are much more accurate and powerful than BB guns. If you want a powerful BB gun then I suggest a multy pump BB rifle.
A firearm is more powerful.Most firearms are more powerful than most BB guns, but there are some exceptions. There are some pro series BB/pellet rifles that are actually more powerful than some small caliber firearms.
PCP's • Precharged Pneumatic Guns are the most powerful airguns made. Most use a scuba tank to charge them and can fire a 50 Cal ball.
It depends on the model and the caliber of the Pellet gun.
You will most likely just pass it.
For a air soft BB gun it's okay not powerful. For a regular BB gun "NO" that is not powerful at all. A Daisy Red Ryder BB rifle will fire around 325 FPS most new pellet Air Rifles will fire at least 1,000 FPS. A really good Air soft rifle will get around 500 FPS.
Depends on the pellet gun, the distance, and the game laws where you live. Most pellet guns should not be used to hunt anything bigger than a squirrel. They do not have enough energy for a humane kill.
In most cases it will be a BB gun. But Pellet guns exceed both the BB and the airsoft guns. Pellet guns can attain speeds over 1200 FPS.