Statistics for occurrence #1 of “Mch” in page 329 of Emilio, Luis F., History of the Fifty-Fourth Regiment of Massachusetts Volunteer Infantry , 1863-1865:

...ied 25 May 74 Pittsfield, Mass. Duren, Charles Maltby; 1st Lieut. and Adjutant. 21 Jan 42 Bangor, Me; single; clerk; Cambridge. 2d Lt 19 Jly 63, must. 7 Jan 64; 1st Lt 11 Mch 64, must. 30 Mch ; Adjutant 18 Mch 65. Resigned 17 May 65 for disability.
...
Max. Freq. Min. Freq.
Entity Corpus Doc Corpus Doc  
Mch 956 851 2 1 0 user votes
William McH 4 0 0 0 0 user votes
A. McH 2 0 0 0 0 user votes
George McH 2 0 0 0 0 user votes

† This entity has been selected by the automated classifier as the most likely match in this context. It may or may not be the correct match.