Rolleiflex 150 shot magazine... ?

[sevo]

It uses 70mm film.

Probably not. The transport mechanism does not look like it, and the original post stated 61.9mm width (which is no size of any recently common 70mm taking or viewing format).

 

[sevo]

This was probably the medium format answer to the 250 shot GG and FF Leica and Nikon 250 motor drive / backs.

Journalists and event photographers might have used these.

I have NEVER seen a journalist with a long film mag, and financed my studies in the early eighties by freelancing for AP and dpa, right at the time when long film mags were most accessible. Journalism was a matter of being fast to press, and long film was quite unsuitable for that. In a pre digital era, delivering large amounts of pictures would subject you to unfriendly comments about spray shooting vs. genuine skills. Cost aside, it wasted the time of the darkroom and editors, on some event obviously short enough that the photographer could not even bother to change film.

In general, long film magazines were restricted to technical photography. The closest to journalism where these show up in photographs of press pits was on tripods at the Apollo starts - and I can't make out whether these are cameras from NASA documentators or PJs (and even if the latter, that would be PJs straddling into scientific documentation).