His parents divorced when he was a young child and his maternal grandfather, James Woolf, helped raise him and exposed him to the outdoors and hunting.
[1] His grandfather was basically a bird hunter, but Jack developed an interest for hunting big game at a young age.
In chapter 9 of his book "The Hunting Rifle", he quotes the story of his first buck, a desert mule deer that he took at young age.
He also wrote two western novels, Conquest and Boom Town, and the autobiography of his formative years: Horse and Buggy West: A Boyhood on the Last Frontier.
O'Connor was well known among shooters and hunters as a proponent of various cartridges such as the .30-06 Springfield, 7x57mm Mauser (.275 Rigby), and for his extensive knowledge of hunting and shooting, but especially for the .270 Winchester with which he collected all sorts of North American big game including the giant moose.
His most popular rifles were built by Alvin Biesen around Winchester Model 70 controlled round feed actions, usually chambered for his favorite cartridge, the .270 Winchester,[5] of which the most renowned one is probably a customized Model 70 named "No.2"[6]: "The wood is quite dense, flawlessly inletted, and rather plain.
Checkering was 26 lpi, in his distinctive fleur-de-lis pattern, and the stock has an embossed grip cap and buttplate.
His last rifle was a Ruger M77 customized by Al Biesen, chambered in the .280 Remington cartridge to the following specifications:[7] “Stock French walnut in a nice grained contrasty piece not so elaborate with Deluxe Fleur-de-lis checkering, ebony forend tip, skeleton grip cap and skeleton butt plate.
280 in Silver on the barrel.”[7] In 2006 the Jack O'Connor Hunting Heritage and Education Center opened at Hells Gate State Park on the Snake River, near Lewiston, Idaho.