this stackoverflow response on the topic is one that quotes the code i used... i have also seen this page linked by several other pages which said this was a workable approach:
http://stackoverflow.com/questions/14598565/serving-206-byte-range-through-nginx-django

i am not blindly following anything - i am looking at all the available information and referred to the nginx documentation - i am using what works and disregarding what does not. so far i have not found an explanation of this situation i am experiencing in the documentation or on forums, hence i am here asking.

in any case, i removed return 206;
the situation did not change.
i am unclear why removing 'return 206' would cause a 200 response to become a 206 response! ;)

" If range requests are
supported, the header will be added automatically."

i am making a simple request for a static mp4 file via curl to nginx 1.7.2.. i am not clear on your use of the idea of 'if range requests are supported' in this context. how would i know if they are supported or not?