The incident happened at Maysirhandir in Newtown just before 11.35pm on Saturday.
Dyfed-Powys Police said one person was taken to hospital after the incident and another has been charged with two offences.
A spokesman for the force said: “Police were called at 11.35pm on Saturday 29 October to reports of an air rifle discharge in the Meisirhandir Estate area of Newtown.
“One person was taken to hospital and later discharged.
“Following an investigation a 29-year-old man was charged with two counts of possessing an offensive weapon in a private place.
“He has been bailed to appear at Welshpool Magistrates’ Court on November 15.”
A spokesman for Wales’ Ambulance Service added: “On Saturday, October 29, at approximately 11.32pm, we were called to reports of an incident in Newtown. We sent an emergency ambulance to the scene and took a patient to the Royal Shrewsbury Hospital for further treatment.”