There was an old thread on the subject of König Ludwig II "mysterious" death in 1886 and the suspicion that an airgun was involved. Figured I would take a quick look at the situation and see if I could add anything to the case. Reference is https://www.hdbg.eu/koenigreich/we…/herrscher_id/7
1. the idea that a Girandoni airgun would have been used is pretty silly. Because, in 1886, any good gun-shop in London, and certainly in some other cities, they sold powerful large-bore airguns.
2. For something like an assassination in a public place, the correct airgun would be a walking-stick airgun. I have a circa 1880 .38 caliber walking-stick airgun with a rotary breech that will completely flatten lead balls against a steel plate.
3) With a good London walking-stick airgun, coming up behind and shooting two men could be accomplished with little effort and then walk away. Nobody seeing the assassin would know that he had a weapon.
4) I think the noise issue is also a bit silly. Of course, airguns are not silent but compared to a black powder gun and the rarity of people being familiar with the sound of a large bore airgun, there is little chance that any "ear" witness would have been able to identify airgun shots. No doubt, the question the witnesses were asked was, "Did you hear any (firearms) shots?) So, even if they actually heard the assassins' airgun shots, they most likely would not have been able to identify them as gunshots of any sort that they were familiar with.