Thanks for the links.
Here is the reply I received from Springfield Armory Museum:
"This letter is in reference to your questions concerning the US M1903 rifle trigger guard with the odd attachment. It looks very much like a variation on the Ely fire control mechanism. Those that we have [no two are alike] are on serial #’s 384371 [dated 10-09] and 251024 [dated 3-08]. Ours are externally mounted mechanisms “that control the angle of elevation and depression at which the rifle could be fired” [quote from Brophy’s book below, p. 438]. Yours has a wheel rather similar to the grenade launching sight wheel. Note that there is a D and an E on the trigger plate behind the trigger guard. I suspect the D is for ‘depression’ and the E for ‘elevation’.
Brophy writes [p. 439] that: “The inventor believed that use of this device would permit the soldier to fire his rifle during times of darkness when he was unable to sight and aim. By doing so, an enemy-held area could have accurate interdiction and harassment fire placed upon it. At least that was the concept.”
“These two rifles [the ones I cited above] have modified trigger guards with an adjustable counterweight that will block the trigger until the rifle is positioned at the preselected elevation or depression.”
The 1909 report [cited by Brophy pp. 439-40] of the Chief of Ordnance added the following to the subject of vertical fire controllers:
“Sixty United States rifles, caliber .30, Model of 1903, are now being fitted with controllers for vertical angle of fire, 30 to be of the design submitted by Captain Frank D. Ely, tThirtieth U.S. Infantry, and the remaining 30 to be of the design submitted by Major William A. Phillips, Ordnance Department. Upon completion of the rifles they will be sent to the School of Musketry for trial and report.”
I suspect that yours is one of these. I hope that answers your question. "
Now I'm not sure what to do with it. - Denny
