First two thing to look for:
1. be sure the butt serial # is present and unaltered or the gun is illegal.
2. confirm the chambers haven't been converted to another cartridge like 45 COLT.
The rest is knowing about what you're buying:
45 HAND EJECTOR US ARMY - Model 1917 PRODUCTION DETAILS:
WWI Military 1917s: These are in the #1 thru # 169959 (the estimated last military #) range but with only 163,635 revolvers completed and delivered by or in 1918, and approximately 7,300 revolvers were delivered partially completed and were not counted in the 163,635 figure. As usual with S&W, revolvers were not completed in order of their serial numbers and all numbers were not used. All were shipped to Springfield Armory.
Both S&W (7300 frames) and Colt were allowed to purchase M1917 revolvers left over when their rebuild contracts were terminated at the end of WWII. (Pate’s Book)
Most early WWI 1917s are marked "GHS" in a circle, (Gilbert H. Stewart), Gov’t inspector, left side frame up near the hammer serial number range 1 to at least 43894. During this period just an S inspector stamp is used w/o eagle head or # following the S. There’s also a GHD Guy H. Drewry inspector from 1930-1957 (with various increasing ranks in front of his name), who was in charge of the Hartford Ordnance District and under whose authority and name, ordnance contractors stationed at the S&W factory inspected guns both for Lend-lease and for ASP (Army Supply Program) contracts.
Middle range guns are marked with a flaming bomb on upper rear left side of frame, beginning c. #42000 to April 1918.
Late war time produced guns are marked in various locations with an eagle head over an "S" followed by a number like S1, S2, S3, S4, S6, S9, S24, S27, S34, etc., in several places from April 1918 to war’s end. These are inspector stamps used on Military guns which are also roll stamped "United States Property” on the underside of the barrel. All have lanyard rings (which is the earliest version; pinned, polished and case colored, not sandblasted and blued). The butt of the gun has a two line serial number (when over 3 digits) and “U.S. Army Model 1917” in four lines.
Exception: Mr. Jinks has said that S&W didn't stamp 'US Army Model 1917', and a circle with GHS inspector or the flaming bomb on all guns until after the Govt. took control of S&W in Jan 1918 because of Govt. dissatisfaction with S&W’s production speed of the M1917.
Photo credite: richcory
Earliest have smooth, concave round top service stocks and circular hammer grooves up to about #15,000. Although, many have been observed sporadically up to the #20,000 range. As with all things S&W, there is seldom a specific serial number cut off. Deletion of the stocks w/concave top and the hammer grooves were of the earliest changes. Jan 1918 is the date given for the request by the military to stop using the grooved hammers and at ~#15000 (Jan '18 went to ~ 16500), but found sporadically thru Feb '18 (17500 to 25000).
The 1917 military issue have round top straps and a U notch rear sight. The change order of Oct 17, 1927 revised all N frames from the rd top frames with U notch rear sight to flat top with sq notch rear sight. Later built frames with early #s have been observed with flat top strap and square notch rear sight; example #113934.
War time 1917s did not have hammer block safeties in the side plate, nor S&W trademark logos, not even commercial models (nor did any hand ejectors) following the war until ~ 1920.
Arsenal Rebuilds: If there’s an extra large stamped # up to 5 digits (sometimes preceded with an R and/or S) in the yoke, yoke cut out, under the barrel, or all three places, it’s an arsenal # indicating an arsenal rebuilt gun. The R may be found on the frame left side as well. Examples:
Tryig to identify 1917 Revolver
Photo credit: Doug4566
Photo credit: Doug4566
&post #9 here:
http://smith-wessonforum.com/s-w-ha...-my-1917-hand-ejector-45-a.html#post139209650
Cylinder hold open detent: In my experience military 1917s had the cylinder hold open detent in the yoke bell crank as did all pre war N frames and some early I and K frames. The cyl hold open detent went away on all frames after WW II with the usual few exceptions that had frames/yokes made pre war. It's been reported that some 1917s do not have the detent as a war time expedient, but of the hundreds of 1917s I've seen all did or at least had the hole with wear evidence that the detent spring and pin were lost. Use caution if you remove the yoke and cylinder from the frame or the spring and plunger can launch across the room.
Plunger shown here in bottom of yoke and has a spring underneath it:
Photo credit: handejector
Serial/Government numbering of 1917s, Smith vs. Colt: Many do not know that S&W 1917s are #d differently from Colt 1917s.
The S&W serial # is on the butt, as opposed to Colt, and served a dual purpose; it was also S&W's government #. The serial number on the COLT US Army Model of 1917 is stamped on the frame, opposite the crane, and a different number on the butt of their 1917 is the government #.
S&W Assembly (factory work) #s: These multi-digit numbers of 3 to 5 digits, are on the yoke at the hinge, in the ‘yoke cut’ on frame opposite the yoke, and inside of the sideplate, for the pre war and post war period to ~1958.
6 Groove Rifling: I would theorize that the 6 groove rifling came about with the advent of 45 ACP hardball ammo and the 1917 Army Model.
The 1917 and later S&W 45 ACP revolvers into the 1950s, have the same 6 groove barrel and the same twist direction as other S&Ws but it's a much more rapid twist than say the their 44s.
Colt used a 1 in 16" left-hand twist. S&W preferred a 1 in 14.569" right-hand twist, Smith & Wesson Handguns by Roy McHenry and Walter Roper, page 97. Also, David Chicoine in his book on gunsmithing the guns of the old west states that S&W top breaks initially had 5 lands but later, with the .45 Schofield, went to 6 lands.
My 25-2 and my 22-4 both have the 6 groove twist.
My Triple Lock 455 British Contract barrel from 1915 has 5 groove rifling.
My earliest 44 Triple Lock from 1910 has 5 groove rifling, my most recent 1990 44 does too, as well as all .44s in between.
1917 military Box, Crate and petrolatum coat dipping procedure pics here:
http://smith-wessonforum.com/s-w-ha...son-i-just-had-get.html?594723=#post140476518
British proof marks: About 20,000 1917s were sold to Britain and will have British proof marks, Post #11 here:
Model 1917 odd barrel markings - can you help?