Most springers suffer the effects of reverse recoil caused by the piston flying forward to force air through the port to the barrel. To get the best accuracy, a consistent hold is required to allow the gun to recoil the same each time. The preferred method is the artillery hold, which allows the gun to recoil freely. The RWS 54 I have uses a howitzer-style moving action to counteract the recoil. It works, but adds weight and expense. RWS 48s and 52s are essentially the same gun, but without the free-moving action. The velocities are the same as the 54, but they're a bit harder to shoot accurately.
PCPs, pump pneumatics, and CO2 guns are essentially recoilless and can use regular scopes, not special airgun models designed to handle the reverse recoil and vibration of the spring guns. I've not shot a PCP, but from watching video, they seem to be insensitive to how they're held. I kind of have my eye on one of the Air Force models as descibed above, but have a lot of other stuff to play with for the time being, including my 54.
