Page 179 brought me to this book. There are statements in this book that I've never heard before.
Window on the East: National and Imperial Identities in Late Tsarist Russia. Ithaca and London: Cornell University Press, 2001
This reference expresses the most prominent non-existent wedge between those that call themselves "Mishar" and others. This reference is not my experience. Different types of Tatars consider themselves to be one thing - Tatar.