Courtesy of Michael Dorosh' CANUCK website.

"I went digging a bit and came up with an interesting little book which has just been released and is presently sitting on the shelves, here in Canada at least. Entitled BLOOD ON THE HILLS^*), by David Bercuson, this book seems to be a comprehensive reference in which the author is brutally honest about both the triumphs and the shortcomings of the whole process of seeing some 25,000 Canadians off to war for the second time in a scant five years. While his prime thread is the history of that [Canadian] excursion, with its attendant and damning political overtones, his emphasis is on the vets themselves, many of whose accounts are contained herein. It's the first definitive thing I personally have ever read on the subject, and I was impressed.

This book seems to be a comprehensive reference in which the author is brutally honest about both the triumphs and the shortcomings of the whole process of seeing some 25,000 Canadians off to war for the second time in a scant five years. While his prime thread is the history of that [Canadian] excursion, with its attendant and damning political overtones, his emphasis is on the vets themselves, many of whose accounts are contained herein. It's the first definitive thing I personally have ever read on the subject, and I was impressed, but I'd like to hear the opinions of others better schooled in that era.

On the subject of tanks and equipment in general, Bercuson is pretty straight-forward, but he fails to answer some of our questions here. It was Foulkes himself who established the very hodge-podge mix of Canadian, British and American weapons and equipment for the boys, but not until February 1951. By that time, our Special Force brigade was training in Ft. Lewis, Washington, and mention is made of Rockingham's changing the mission of the armour from anti-tank to armour-infantry co-operation:

...by December the NKPA and its T-34s were history, and the Chinese never used armour in Korea...

Bercuson goes on the delineate the weakness on the M-10:

...it was dangerous; its open turret invited any enemy soldier with even a mediocre arm to lob in a hand grenade. Rockingham was uneasy about using the M-10s. He soon shifted the armour squadron from anti-tank training to armour-infantry co-operation. But that too was useless, because the Korean terrain would not allow infantry and armour to advance together, while using armour in the attack forced an army to stay road-bound.

Bercuson's only specific reference to the replacement of the M-10s comes a bit later in the story, once the 25th Canadian Infantry Brigade Group had landed at Pusan on 4 May, 1951:

The serious work began on 5 May in a tropical downpour. Rockingham arranged for the replacement of most of the brigade's 17-pounder anti-tank guns with U.S.-built 75mm recoilless rifles, which had proved effective at providing with close, direct-fire support... several days later, Ottawa authorized Rocky to arrange to swap the M-10 tank destroyers of C Squadron, Lord Strathcona's Horse, for Sherman M4A3 tanks, supplied by the U.S. Army.... these two major changes of equipment were not complete until mid-May, delating the training schedule...

So it looks as if the M-10s went directly to the U.S. Army, to be reallocated/disposed of according to their whim.
 

 ^*) see Michael Dorosh' CANUCK website for a discussion on the book BLOOD ON THE HILLS: THE CANADIAN ARMY IN THE KOREAN WAR by Dr. David J. Bercuson.