Who was your gr-grandfather? What guerilla outfit did he supposedly join? As for reasons, maybe it wasn't really an irregular or guerilla outfit he joined. Floyd's Virginia State Line, which had over 100 Pike Countians among its ranks, was a legitimate Confederate military unit under the VA Adj. Gen'l but not part of the PACS. Many later outfits, such as Prentice's 7th Cav Btn, were almost universally referenced as guerillas by the Union press but were legitimate parts of the PACS. It could have been just a matter of the winners writing the history and filling out the forms.
Tell us more.
Randall