It happened Monday night at the store located at 508 E. Lancaster Avenue.
Police say the four men entered the store around 8:30 p.m. Three of them made a small purchase and left while the fourth man hid in the stock room until closing.
At 9:00 p.m. and a cashier and assistant manager began to close the store.
A short time later the suspect emerged with a dark ski mask over his face, light-colored glasses and a curly wig over the mask.
Armed with a rifle, the man walked to the front of the store and ordered the two workers to get down.
The man then fired a shot but, because there was no damage and no bullet found, police said it may have been a cap gun.
The man then forced the assistant manager to open the safe and took an undisclosed amount of money.
The man who committed the robbery is described as a Hispanic male with facial hair wearing glasses and a very dark curly wig along with a white LA Raiders baseball cap with a black brim.
The three other men are described as:
-A white or Hispanic male in his late twenties to thirties with some facial hair, wearing a blac hoodie sweatshirt, blue jeans, red and black sneakers.
-A black male with short black hair and moustache, wearing glasses. He was wearing a bright red hoodie with "READING" outlined in white letters across the front of the sweatshirt, blue jean shorts worn and torn across the front and knee area, and white sneakers with dark socks
-A black male with short black hair, wearing glasses, a blue and black fleece jacket, blue jeans, and black shoes.
Anyone with information is asked to please contact the Cumru Township Police Department at 610-777-9595.