The B45-3 , another Chinese rifle, you don't see many of these around due to the fact that they are too easy to get over power ( UK ). Mine is a .177 model, originally it would not hold air for more than a few seconds. I stripped the mechanism down and could not believe how simple it is. All it need was a good clean and correct lubes on the metal and seals. Once this was done I found that 4 pumps gave a consistent 10.5 lbs and 5 pumps was nearly over 12lb . Never tried 6 pumps as there is a danger of blowing the seals. the gun is light and very point able, the 12 shot magazine works OK but due to the fact you have to pump between shots this does not make it a fast shooter between shots.
Rregardless of calibre the magazine is .22 so .177 pellets fit loosely and you have to be careful when loading not to crush or get them stuck in the breech.
Open sights are quite good, there are 11mm grooves to fit a scope but they are not great, a small red dot sight works well.
Criticisms of this gun would be the effort to pump and you need good technique so as not to twist the lever. the trigger gets correspondingly stiffer as you increase the pumps but the trigger is predictable. On the plus side it is light , has no recoil, the stock is comfortable and overall I think it looks good. Accuracy is very good.
Below is a picture of the gun in action and a strip down guide below that.
