Everyone is pointing out the lack of muzzle break or hydraulic recoil damper, but the bigger problem is that this is in a field gun mounting. She better hope that she gets a hit (and a kill) in the first shot because if the dragon goes airborne, she is going to have a hell of a time trying to engage it.
Ideally, you would want 360 degree traverse and 90 degree elevation. It looks like she might be able to do 60 degrees of elevation but if she needs to traverse more than 5 degrees, she is probably going to need to re-lay the gun.