I thought NSRA Club Pistol would allow any shape of projectile because it is mostly shot with .22LR so domed pellets were an option. That would include a lot of good quality pellets from the best makers.
But Rule 9.2.6 seems to specify that air pistols must fire flat heads. That is very annoying. Whoever thought that up was not thinking that someone might want to shoot some comps with a .22 air pistol.
Pellet choice would be limited.
Suitable gun might have to be a custom job.