Yes. Pump, Spring and PCP (PreCharged Pneumatic) are all more powerful than a C02 system
No
Whether or not an air rifle is more powerful than a cross bow depends on the air rifle or cross bow. Generally a hunter's cross bow is more powerful than a child's bb gun. However, during the Napoleonic Wars, the Austrians had an extremely powerful repeating air rifle. It could shoot several hundred meters. Austrian solders armed with them could shoot Napoleon's solders from such a great distance that Napoleon's solders could do nothing about it. Eventually they ran out of bullets.
lightning is more powerful than air
no it is not more powerful than air because air could scatter the electrons and protons so lightning disappears that's why air is more powerful.
Not designed for this type of modificaiton.
lightning
Not recommended. Not desgined for a more powerful spring.
Only if the scope is designed for air rifles. Regular firearm scopes are made different than air rifle scopes and many will break if used on an air rifle because the recoil is different than a firearm.
you can't
Yes it can but getting the current rifle "Tuned" by an expert will get you better results. Tuning will make the spring and trigger perform better.
If you are asking "WHAT" not "Where" is the most powerful under lever .177 air rifle. Then I suggest the "Hatsan Torpedo 150 air rifle." I comes in at around 1250 FPS where as most of the other under levers fire at around 950 to 1000 FPS. However Under levers are not the most powerful air rifles. The PCP (PreCharged Pneumatic) Class of air rifles are the most powerful air rifles. An "Air Force Condor and the Evanix Rainstorm" fires a .177 cal pellet at 1300 FPS.
Generally, no. The size is the same, but the mass of the projectile is not. And a .22 rifle bullet is propelled by gunpowder, with a much higher muzzle velocity than an air-powered pellet.