Backspace should be the key to use to change cannon rounds, but if you have remapped some of your keys it may not have updated the button.
To do this go into 'setup', choose 'key mapping', select the 'gunner' keys and now assign Backspace to "Select Primary".
The coaxial MG is considered the secondary gun in the turret, so just set the "Fire Secondary" to whatever suits you. (I think 'N' is deafault)
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Snefens
-=Aces High Training Corps=-
