No due to the fact it can explode leaving you weaponless.
I'm curious has anyone used the HandCannon at Armadyl yet and know if it's any good?
And you CAN cross the Arma grapple point with a familiar ( I do it all the time)
And you CAN cross the Zammy river with a familiar (I did it with my turtle like 4 days ago)
I am thinking Jagex may have updated those things