Buy lots of pellets!
I had an LP5 PCP (the LP5 was originally sold as CO2) sold it and now have an LP50. I think the semi auto mechanism is the same. The cylinders of the LP5 don't have an air gauge. They may have a pin that pushes out when full. My LP50 gets about 100 shots pushing 7gr pellets at 500fps. Also the LP50 added some barrel vents to reduce muzzle flip. They're both as accurate as most other high end match pistols--10 shot groups that are a single small hole at 10m. Krale in the Netherlands sells the 5 shot magazines. The Steyr multishot is probably the best (most reliable) multishot match pistol available.
It is a super fun pistol. The trigger of the LP5/50 isn't as good as the LP10. It isn't as adjustable and has some creep. But its still quite nice--predictable/consistent.