"I'm really hard to excite," Koontz said.
One thing that has thrilled him is hunting wild sheep in some of the most remote areas of the earth, which to Koontz ranks high above all other big-game pursuits.
"It really has to be in your blood," he said of sheep hunting.
A native of Bedford County, Pa., Koontz was initiated into an avid hunting family at the age of 12 when he was given his first shotgun. He still keeps it among his gun collection, numbering over 20 weapons.
"I can't say I ever shot anything with it, but I carried it. I shot at things," he said.
Koontz quickly progressed to hunting small game - mostly rabbits and squirrels - to deer and then on to "bigger and better things," he said.
He became hooked on pursuing wild sheep when he joined his first hunt in 1966 in Alaska.
From there, Koontz has taken on some of the wildest, harshest climates in the far reaches of Nepal, Afghanistan, Russia, Iran and Canada.
Hiking for days at altitudes close to 20,000 feet in some places, Koontz withstood rough terrain, little food and thin oxygen levels that often gave him headaches.
During a trip to Nepal, Koontz said it took three days traveling on foot to reach hunting country, which took him, other hunters and 20 porters carrying supplies on their backs over three, 10,000-foot passes.
Just getting to the animals' natural habitat is hard enough. Tracking the sheep is a challenge in itself.
"You have to stay out of sight. They have eyes like an eagle," Koontz said. "It's the hardest hunting."
In sheep-hunting terminology, a "grand slam" means taking one each of the four North American wild sheep species. Koontz has two each.
He also has taken one of the dozen wild sheep species, categorized as the "World Super Slam."
Of all Koontz's sheep, the most impressive is an Argali, the largest species in Mongolia, which is mounted life-size in his basement "game room."
Koontz, a father of six and a grandfather, has hunting stories that could fill a book.
But the stories haven't ended.
Though he said he's too old to go sheep hunting now, Koontz still takes a group of 30 out for pheasant hunting every October and already has five weeks of deer hunting planned this year in Colorado, Texas and Canada.
"I've had a pretty full life ... I've worked hard and I've hunted hard," he said.
Some of Koontz's collection will be on view at the Fulton County Sportsmen's League's second annual Outdoor Expo Saturday and Sunday at the Fulton County Fairgrounds, just off old U.S. 30.