All,
Further to the above, please note that I am attempting to post a number of images of B&G documents. I will answer questions but am not planning to expound on much of this. (I cannot expound about that which I know so little).
Note the many varieties of projectile - up to 13" shells assumed to be for mortars. There are invoices here with letterheads showing Memphis Ordnance Works, consignments to Ft. Pillow, and activities up to late 1864 at least. The Memphis Ordnance Works (Maj. Wm. R. Hunt, Cmdg) relocated to Columbus, MS and operated closely with the Briarfield Arsenal. Briarfield was under a contract to the CS Army to provide ordnance to the government. That contract stipulated that the government would provide the iron and other production materials that allowed Briarfield (Privately held) to produce. Eventually material shortages caused production interruptions which led to bankruptcy/buyout in about March of '64. A board of appraisal was convened and the assets of Briarfield were transferred to the Selma Arsenal and as I can piece the story together these assets were sent to Columbiana, AL where the "Briarfield Arsenal" continued to operate. Now, when you get ready to discuss markings on projectiles consider the "G" as potentially coming from the "G" in Brook and Gaynor. Further to this last thought, also operating in Columbus, MS as early as 1861, also providing ammo to the facilities along the Mississippi was another firm named Quimby & Robinson (Robinson?). Another foundry NEAR Selma (about 110 miles but in period travel that was relatively close), and which could shed light on the mysterious Selma associated "Q". Just thinking out loud on that.