A military jury at a court martial in Calgary also acquitted Watts of breach of duty.
But the five jurors convicted him of unlawfully causing bodily harm and negligent performance of military duty.
Cpl. Josh Baker died when a Claymore anti-personnel mine peppered the platoon on a practice range near Kandahar city in February 2010.
The defence countered that Watts had no training on the C19, so handed over responsibility for safety to his second-in-command, who was an expert on the weapon.
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