... why they couldn't have just taken the dragons to some far-away field and fired them through gateways from there. I'm not sure why it had to be in an enclosed cavern. It would have been a great strategy for using them all along, since it a) allows you to fire from point blank range against the enemy, and b) doesn't expose them to the risk of destruction or capture, leading to most of them being knocked out of working order. Not to mention getting rid of the percussion issue you mentioned, while maintaining the same functionality.