David those look like air hammer mufflers joined together. I tried to adapt one once to a rifle and blew it out into the middle of a pond. Last attempt at that.
Not sure if the concept translates to airgunning, but in the world of military surplus firearms (where I got my start) the term "Bubba" means someone who made alterations to the original military configuration of a weapon. Often with poor execution and to the detriment of the historical value of the piece. Think sporterizing a rifle, whereby the stock is chopped down, the military hardware such as iron sights and slight swivels get tossed, and the receiver is drilled & tapped for a scope. As was the case with countless war bring backs in the past. This is generally frowned upon by collectors today because these alterations detract from the original intended appearance and purpose of the weapon for military use. So a "bubba'd" milsurp was one that was hacked up, turned into a half-assed attempt at a sporter gun, and stripped of its historical significance and value as a result.The idea may not resonation as well with air guns as these are considered sporting implements from the get-go, and making personal modifications to aid in their intended use is not as taboo'd. And so the line the blurred on what alteration is generally accepted as appropriate, vs not. However, I believe that there is definitely a line that when crossed, has negative consequences for the value of the gun. The the most common "alteration" is the missing front or rear (or both) sight which doesn't constitute a heinous crime, and is at best just an annoyance for the purist who wishes to see the gun complete as it rolled out of the factory.But my question for the group is this; what is the most egregious modification you've come across in the wild? What was the hack job, and what gun was the victim of abuse at the hands of Bubba??