don't have a gamo and am very happy with the gun i have, but a gun with some of the following would get me very interested
a steel Picatinny/stanag type rail for scope mounting, with the rear open sight also mounted to this, may also be possible to fit the front sight too
an action similar to the hyscore pistol, this way can keep the 18" barrel for legal reasons but keep the overall length short
a light adjustable trigger, trigger could be factory fitted with an extra part which could be removed cover the safety out of the box issue, some restricted power motor bikes were simply fitted with a washer blocking the exhaust
side lever cocking or under lever with a less ugly front sight/lever latch unit
quick reliable loading that will never put your fingers in danger(anti bear trap does not count)
easy barrel change
stainless steel exposed bits
target style stock
please :0
fin
