Hello,
Pumps are great!! They are simple to use, and very convenient... good for keeping fit too!
Dependant on required pressure, they are not too strenuous to use... I fill my Daystate X2 from empty in about 30 strokes, but anything requiring more than 200bar can be quite hard work.
It is important that the air pumped into your gun is completely moisture free, so this means that gun and pump should be at exactly the same ambient temperature, ie if you take the pump out of a warm cupboard into a colder temperature, there is a chance that condensation will form inside the pump barrell, which will be transferred into the guns cylinder. I always put my guns and pump into the same room for at least an hour, so that the temperature equalises.
It is also VERY important that you clean the pump adaptor and rifle valve before using the pump, as and muck from either will be pumped into the gun by the high pressure, and this can damage the seals.
If you are careful with it's use, it is a quick, and convenient way to recharge your gun.
Incidentally, you can now buy an inline moisture filter for the pump... cost about £40.
Regards,
Doug