The victim then managed to disarm the suspect after being shot in the leg, according to the victim's son.
Deputies said Jerry Harryman, 66, of Milwaukie, got into a confrontation with William Young, 59, also of Milwaukie, while the two were in line at the store at about 3:40 p.m Tuesday.
Young's wife, Dorothy, his son and his 9-year-old grandson were also with him in the checkout line.
Dorothy Young said Harryman was behind them in line with a cart holding nothing but ads and no products and he seemed to be looking over her shoulder as she typed in her bank card's PIN number.
She said her husband told Harryman to back off but he refused.
The argument escalated to a physical struggle at which point Harryman pulled out a semi-automatic handgun and pointed it at Young's chest, according to his wife.
"They were wrestling, and the man pulled out the gun and pointed it at my Dad's chest," Williams' son, who did not want to be identified, told KATU News by phone. "Dad forced the gun down, and the gun went off and hit my dad in the leg."
"The bullet went into his thigh above the knee, and out the back," Young's son said. "It didn't hit an artery or anything."
Dorothy said that after he was shot, William, a Vietnam veteran, managed to put his finger behind the trigger of the gun during the struggle to stop Harryman from firing the weapon again. Otherwise, she said she's convinced Harryman would have kept firing.
Their grandson said he did not see much but remembers hiding. He was not hurt.
Young's son said his father wrestled away the weapon from Harryman and got the ammunition clip out of the firearm. "I'm glad he was there to protect me, my wife and my child," he said.
Dorothy Young said she remembers saying "you can't have a gun in Fred Meyer" as the struggle ensued.
After the shooting, deputies said the two men continued to struggle and bystanders and store security personnel eventually entered the fray, subduing Harryman.
Deputies said store security personnel handcuffed and restrained Harryman until law enforcement officers arrived.
Investigators said Harryman had a concealed weapons permit valid in Clackamas County. Following the incident, Harryman was arrested on an assault charge and his concealed weapon permit has been revoked, deputies said.
Both Harryman and Young were taken to local hospitals. Young has a non-life threatening gunshot wound to his leg and Harryman had minor injuries including abrasions from the scuffle, deputies said.
Joann Rothi said she was shopping in the meat section when the shooting happened.
"To me it sounded like a book dropping on the ground - just a funny little sound," Rothi said.
She said she saw employees quickly moving toward the back of the store and "gathering people with them as they went."
On Tuesday, Fred Meyer spokeswoman Melinda Merrill said store employees responded "by the book" to the situation and they receive training for these types of incidents.
Hospital officials said Young has been released. He did not want to be interviewed about the incident. "He's a tough old bird," his son said.