Service on the Mexican Border 1916

This is good luck pocket piece given to soldiers, usually by family members to take on deployment. This NGC MS63 brown (and probably antiqued) is in unusually good condition and quite rare thus. Many of these soldiers were part of General Pershing push into Mexico to stop border incursions and Pancho Villa. While I have a few examples here in the Moneta Museum, this photo was borrowed from on-line sources in order to display an undamaged example, carried in a pocket, most examples are beat up and worn. There seems to be undocumented varieties. See NGC Census for all Mexican War Types (these are not documented in published books yet).
As shown below the catalog reference for these dollar-sized pieces is HK ["So-Called Dollars"; by Harold E. Hibler and Charles V. Kappen]. The catalog number range for these similar pieces is HK, showing the same WWI type soldier aiming a rifle, but those are WWI and this type is for Border Wars of 1916 - 1917. WWI types in HK are: 892 - 894, in bronze (892, 35mm), brass (893) and white metal (894). There's more to learn because it's clear that this specimen in bronze or copper. Recently an 'SH' reference became available for some in the series, by Jeff Shevlin & Bill Hyder.
There's an on-line HK now available at this: https://www.so-calleddollars.com/index.html