Basically all you can do is check function.Put in a CO2 capsule, load with Crosman Veminpells, and shoot it. One of the general faults is that the loading shuttle that flips back and forth can have too much play due to a couple of reasons.One is that the cam ring that operates it has a square hole that gets rounded off through use.The other is that it is not clamped properly with grub screws on the square operating rod.All the faults are easy to put right and spares if required are available from a number of sources. A must have pistol for all air pistol enthusiasts.

Baz