Yep weird eh? I think it allows flexibility depending on the position where the lamp locks in the socket. The base is a position oriented type with the pin. The bulge where you see it shows exactly the position the lamp was operated.
I have actually seen two 1650 Watts Metal Halide bulb burning horizontal position at Underwriters Laboratories at Northbrook, IL where I used to work there about than 18-19 years ago. They were testing the fixture at one department.
This Lamp has been designed this way to stio swirling of the arc when lit, which can cause stroboscope on Television Camera's when televising a Sporting Event,
Cool lamp it's the only size I am missing to complete my collection of US metal Halide Lamps,
@streetlight98 the position oriente mogul base has a protruding pin in the base shell, so it will only go in a special socket and it locks into position so the curved arc tube points upward, following the upward bowing of the arc stream.
Cool lamp it's the only size I am missing to complete my collection of US metal Halide Lamps,