Seems a bit low, especially considering armor.
Without armor I can imagine a doberman drone weighing about the same as a large dog, so let's say about 70kg/140lbs thanks to the use of light-weight metals and carbon.
But then, it's a combat drone and it's got plates of metal slapped to its side. That stuff adds weight.
With that added, if it's got decent armor (and don't forget, weapons and ammo weigh a bunch too), the weight should at least double.
A formula along the lines of "body x ##lbs" would be nice, but imo armor should be included too, so something like (body + armor) x ## would make more sense.
The table Shaidar posted is really nice, though. And much simpler.
But again, I'd add weight for weapons and armor.
