Morse O'Berto(1910-1980) developed his triggerless assembly in the late 1940s and early 1950s and manufactured them in his own machine shop located at Iron Belt Wisconsin, just southwest of Ironwood Michigan. He received a patent for the device in 1956(Pat No. 2741065). He made two sizes that I am aware of and those were numbered 300 for a size that fit #3 jump traps and a 400 size that fit #4 jump traps. Later small sized assemblies have no number(thus 3 different pans that I have seen). The trap collectors guide by Andrewski and Parr list a #200 that I have not seen. If it is consistent with the other sizes, it would fit a #2 size jump trap. Each of the assemblies is sized to fit traps with high arched jaws. I have seen #300 installed on #3 size Victor and Blake and Lamb jumps as well as #13 Victor jumps. I have a single #300 that is installed on a double underspring that must have originally been a Oneida Community #3 trap. I have owned traps with #400 assemblies that were installed on traps that originally were #4 or 14 jumps as well as the trap that Morse O'Berto installed most #400s on, the #44 Blake and Lamb(he sold many of those into the 1960s). Several years ago, 160 user reported that he had some longspring traps that someone had installed triggerless assemblies on. I think that would have required some modification of the assembly or would have resulted in an off centered pan. Since trappers could purchase the assemblies separately, they might be found on almost any trap of appropriate size and configuration.
