Pretty sure that was a 444 Marlin rechamber. Picture looks familiar from years ago.
I won't mention a name, but I personally know a fellow that shot a 44 mag in a 309JDJ. The crazy thing is it did not rupture or stretch the barrel of frame. I am pretty sure JD has the complete gun, if I recall correctly. That is pretty wild running a 44 jacketed bullet through a 308.
I have heard of guys stretching frames with the 375WW. I have one with a brake. It can be an uncontrollable monster. I have shot some crazy stuff in encores and Contenders. I have no idea why one would knock the hide off their knuckles and bloody their hands, then laugh about it and brag what a heman they are. All the while never hitting a darn thing to boot.
Macho, manly, brave, there is a fine line between that and stupidity.
Ben, I know you like the octagon barrels. I will give a heads up,the old octagon 44's with external choke tube, take the tube off and the barrel is around 7" or so. I had one that came in a package deal. It was a "biter" for sure. About the most wicked recoiling rig I ever fooled with, but the darn thing shot good and accounted for several deer critters. Makes my knuckles hurt thinking about it. And I am not so sure the knot on a bone on my right hand was not caused by that rig.
Jeff