A 29-year-old captain who recently assumed the helm of the IDF's Sniper School, Hartman formerly headed the army's Marksmanship School, which he reorganized from scratch. He was "in charge of shooting for the whole Israeli army," he recalls.
"Every bullet that's shot in the army is [fired the way] I taught someone to do."
This is no small feat for any immigrant, especially an American who left the California beaches 10 years ago in search of himself and wound up in an IDF uniform.
Hartman, who had never used a rifle until he came to Israel, turned out to be a crack shot. When he joined the army a decade ago his bullets hit in a small grouping on the target and shocked the staff. His commanders would bring people just to watch this neophyte shoot. Hartman has won the IDF shooting championship six times.
Historically, Israeli soldiers have been notoriously bad shots. The first time the vast majority of Israeli youth shoot a weapon is during basic training.
"When I was in basic training we did only two days of shooting training," says Hartman.
"Now there is a schedule for every step in the army. There is a list of exercises that every soldier must do," Hartman adds.
Recruits now have a total of 42 lessons in seven weeks of training and are recording a stunning 86.9 percent accuracy rate on the range.
"When I started we were around 5 to 7 percent. We would hit the target five out of every 100 shots fired. And now we are close to 90 hits out of 100.
"We are by far the army that shoots the best in the world," Hartman continues. "What the army has realized…is that a soldier is not a soldier if he doesn't know how to shoot."
Four years ago, when Hartman took over the Marksmanship School, "no one in the IDF thought marksmanship was important."
The first thing he did in his campaign to improve marksmanship was to create an awareness of the need for proper, orderly training. Then he designed a course of instruction that he believed would turn the soldiers into professionals.
"My field is motivation. If you are not motivated to shoot you are not going to hit the target, even if you know what to do. You have to want to hit the target.
"I try not to offend anyone, but I'm in a position where I have to go to high-ranking officers and tell them they've been doing a lot of stuff wrong. Tell them to wake up and smell the coffee. We're doing things better now," he says.
Hartman gets along with soldiers and officers alike. He's able to make fun of himself and still remain serious, a trait not usually associated with the traditional macho Israeli officer.
"I'm not a handsome guy. But I've got a good personality. They call it kesem ishi — charisma. That's what they call people who are not handsome," he says, laughing.
The proud Givati veteran was singled out as an exemplary officer for his work and promoted to captain last Independence Day.
"I was always Zionistic. I watched the Entebbe operation on TV and cried and said, `That's what I want to do.'" He made unofficial aliyah from Los Angeles at age 19, signing on for a one-year program at Bar-Ilan University. His mother made him sign a contract stating that he wasn't going to join the army, and that he would finish school and return home.
"At that age I was in that soul-searching sort of thing and I didn't like what I was when I found out. I was a spoiled kid on remote control. I was supposed to be a lawyer like every Jewish kid in the United States. I wanted to make more out of myself and I had to grow up."
He joined the army under Mahal, the 10-month program for foreign volunteers. He confides easily how he broke down in basic training.
"I took off my gear. I said, `I want to go home. I want California. I want the beach. I want women. I made a mistake.' My sergeant came over to me and gave me a kick I'll never forget."
Hartman pulls out his loaded .44, which just about reaches his knee when holstered.
"I bought this gun in case I ever meet that sergeant in the street," he says, grinning. "That was my crisis and that was my wall and that kick got me over that wall. Today, I teach commanders how to get other soldiers over that wall."
When his first stint was up Hartman signed on for another year and then decided to do three years, the compulsory tour for all young men.
He stayed on in the Givati brigade as a shooting instructor, finally attending officers' course after six years in the service.
"I'm not upset that I didn't go back home and become a lawyer. I may not be as rich. I don't have a house or property; I don't even have a girlfriend," he says. "But the inner satisfaction…If I can save one life with what I teach, then maybe that is why I am in this world."