On my daughter's sub-12 air rifle, it's just a case of poking an allen key in through a little hole to engage with a hidden screw head, and winding it up.Obviously I assume it's not just change a part at home since it's restricted and would need to go to a smith and be done officially
but I'd feel dumb if I find out later I should have looked out for a certain type as the upgrade is easy rather than sell and rebuy once I have a slot
It goes up to insane power, no fancy tools and no 'smith needed.
Not that we would ever do such a thing, of course.....
(It's a Ripley Rifles custom build, btw).
.. great fun.

