X-Ringshooter - Since your Springfield M1911 pistol magazine is a “charger” just as much as any enbloc or stripper clip (all of which I find interesting and part of the story of ammunition), I don’t see any harm in going into some detal here. I don’t know what info you have received on the magaine off-Forum, so sorry if I am duplicating.
Only Springfield Armory rolled the edges of the magazine body over the magazine bottom plate to hold it in place. They felt this was a better, more secure method of attachment that the pins used by Colt and Remington-UMC. They said so in a letter to the Chief of Ordnance, dated April 13, 1914:
"There is enclosed herewith a magazine for the automatic pistol cal. .45, model of 1911, as manufactured at the Armory. It will be noted that the magazine base is secured in the magazine body in a a different manner from those of Colt manufacture. It is believed that the S.A. method of manufacturing the base is superior and the construction stronger. The magazine can be manufactured more economically by this method than by the Colt method and it approval is recommnded."
Springfield’s manufacturing technique was approved by the Cuyief of Ordnance on April 17th, 1914. Springfield was notified on April 19th and acknowledged receipt of that notification on April 12rd. All of their magazines were made by this proces.
Col. W. S. Peirce, Commanding Officer of Springfield Armory wrote the chief of Ordnance March 12th, 1917, further explaining their process for manufacture of the M1911 magazine:
"The bodies of pistol magazines as made at this Armory are folded from sheet steel and welded by the oxy-acetylene process. The original magazine body as supplied by the Colt's Fire Arms Manufacturing Company was made from a drawn tubing which was purchased in Germany, but as the source of supply has not be available for some time, the bodies at present being made by the Colt's Company are made in the same manner as bodies are made at this Armory. It is not believed that a chrome vanadium or other alloy steel can be successfully handled under the methods now in use for making bodies, and as no American manufacturer is known who can make satisfactory tubing even of a low carbon steel, it seems useless to attempt to obtain a tubing of an alloy steel. The opinion given as to the practicability of the use of an alloy steel is corroborated by the Colt's Patent Fire Arms Mfg co."
The first order of Springfield-made M1911s was completed in March 1915. In october 1915, the requirement for a lanyard loop on the base of the magazine flor-plate was discontinued. After that, due to sufficient quanitities of magazines on had, few magazines were manufactured with the lanyard loop. They are quite a bit rarer than those Springfield magazines with it, although both types are very scarce today.
The above should pin down the manufacturing era of your magazine to from early to late 1915.
Reference: “U.S. Military Automatic Pistols 1894 - 1920,” by Edward Scott Meadows, pages 191-192. If one has an interest in U.S. Military Pistols, and does not want to buy all the books specifically on individual makes or models, this is the book to have. It is a must in any good library on guns, in my opinion.
About your spurs, if the Civil War guys have pinned them down to the period you mentioned, that may be as definitive as it gets. In the post-Civil War period, the military had no money, and much equipment was used as is, or modified, for use in the Indian Wars that occured after the Civil War. I can’t speak for Spurs, but some Civil War equipment was still be issue past the turn of the Century, into the early 20th Century. Not only was the military broke, but it was tiny compared to the manpower utilized in the Civil War, so there were warehouses full of left-over equipment.
Hope this is of some help and interest.
Edited once to correct one word’s spelling only.