The third armed invasion lasted fifteen years, and Chilcotin literally stood on guard for Canada and the USA. During the 1950s the American and Canadian governments expected the USSR to launch an atomic attack at any minute. In response to the threat, they set up a series of early warning air bases to alert the military in time to launch a counterattack. A site near Puntzi, which had figured so largely in the war of 1864, was chosen as one of the thirty-four stations in the Pine Tree Defence line. The Puntzi Mountain air base (everyone called it Puntzi) came into being in 1951 and the military rebuilt the Chilcotin Road between the base and Williams Lake. The contractor, Northern Construction, hired local men and machinery. Bill Bliss, Harold Stuart, Gordon Jakel and dozens of others worked on the project.

The base was built on forty acres of the Knoll ranch at Chilanko Forks. Arthur Knoll was living there, but his son Ollie (Alvis) actually owned the place and he had his headquarters across country at Chezacut. The base was well established before Ollie and lawyer Jack Cade drove over from Chezacut to investigate. Security was tight at the base. When civilian worker Phil Robertson delivered the mail inside the base, he was accompanied by an armed guard. The officers were taken aback when Knoll and Cade rode in from the bush. They immediately took steps to secure the area. Arthur Knoll, who did not mellow with age, took exception when they locked a particular gate. He put a lock on it too. Unable to stop him from doing it, base officials finally gave in and left the gate unlocked. There is no evidence that the unlocked gate threatened national security.

Old Knoll kept pigs, and the cooks on the base saved scraps for them. They felt sorry for him, thinking he was poor (he wasn't) and neglected (he fought with all his family), and they slipped him goodies too. He did well from the base, but it was years before Ollie was paid for the property.
In terms of population and services, Puntzi was the biggest and most modern centre in Chilcotin. It was seven miles from the barracks to the operations buildings and a bus made six trips a day taking crews back and forth on shift changes. The base had a 6,000 foot airstrip, the second longest in the province, and there were thirteen D8 bulldozers on hand to clear snow off it in winter. Radar with a 150 mile range scanned the skies all day every day and the base was in close contact with the air defence base in Seattle as well as the Royal Canadian Air Force base at Comox. Along with the administration buildings and four radar bubbles, there were living quarters on the base for 100 US airmen. The base hired local people too and the community of Puntziville sprang up to house the civilians, many of them Chilcotin born, such as Robertson and Clarence Mackill. Harold Stuart did a lot of work at the base and so did others. There was a school at Puntziville and for a time one of the US officer's wives taught there. Settlers drove miles to attend movies, parties, the pub and ball games at Puntzi, and the base was a bonanza for Chilcotin and Williams Lake. Trucks ran steadily between the laketown and Puntzi. Hodgsons couldn't begin to keep up with the freight.

The US eventually turned the base over to the Canadian government, and it wound down, closing completely in 1965. Most Puntziville residents left, but others came later. Some things from the base were sold, some found their way into local use, but much of it was torn down and destroyed, much to the disgust of residents. The Drummer is still trying to reclaim the land where the base was.