Everywhere in Cambodia you can go to a Cambodian shootingrange. You can shoot with small guns like revolvers to AK47 and rocketlaunchers. This Kiwi from New Zealand launched his rocket naked!
http://youtu.be/fLfPOTATdWA
Cambodian shooting range
The Cambodia shootingranges have a lot of guns. You can ask the tuk tuk driver (for example ask Thom) to bring you to the Cambodia shootingrange. You can shoot normal or go crazy as this guy above. They will offer you so many weapons that you can spend a lot of money. Just pick you dream weapon and do it once.