Hi Marcus,
So the first illustration you posted is also a later version of the original which, added to my two copies, makes Taccola be be proud of so much resource to his work.
Nevertheless what we are facing is imaginative/stylized ideas, produced by the master of devices not brought into practice. In other words we all agree that, the functional version of hand gonnes being used by horsemen was yet to be established, the hook being so far an illustrative appendix. I am not versed in dynamics but, i take it that the implements designed to hold still the gun, would have to be subject to serious ponderation as, it the shooting caused some sifnificant recoil, would not only be the saddle rest to tackle the impact but also the shooters breast sternum

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