Canadian towed AA gun trials?

[Roger Lucy]

These could be pictures from the trials that DND undertook in Petawawa in March 1942 at the behest of the Britsh Ministry of Supply to simulate the movment of a Bofors on a tracked mounting in arctic and mounntain conditions. DND agreed to send a Bofors gun to Petawawa where there was already an Atkey trailer and Loyd Carrier that could be used as the mountings. The trials are described on pp 62-5 of my Secret Weaposn of the Canadian Army (Service Publications, 2006) but I only found pictures of the trials with the gun mounted on the Lloyd Carrier.
The gun was tested on the Atkey trailer on 15 March, 1942 a D-7 Caterpillar tractor was used to tow it. The towing trials went well, the trailer being towed over 10 km of snow- covered roads and light bush. Drifts up to 1.2 metres presented no problems. It remained stable even when tilted up to 30degrees. The firing trials were not so encouraging. Four to six round bursts caused the trailer to sway, leading to wide dispersion. Single shots were only possible once every ten seconds as the sight had to be relaid. As a result, it was considered not feasible to engage ground or air targets with automatic fire, and only with carefully measured single shots.