Frame and Slide Markings

Always Examine The Markings With A Magnifier:
The markings that were applied to a metal surfaces of various military 1911/1911A1 pistols were applied both before and after the final polishing/finishing was done.  Some specific markings, such as the final acceptance mark and the Ordnance Acceptance mark were always done after finishing.  Other marks such as the standard slide manufacturers identification slide legend were always done before final finishing.  Still other marks such as the serial number were (depending on the time period and the manufacturer) applied before, after and both before and after.  An example of both before and after is the serial number of the post mid 1943 Remington Rands or Ithacas.  

The “NO.” prefix was roll marked at the same time the right hand receiver legend (United States Pro…) was marked.  Then after finishing and inspection, the serial number was stamped. 1911A1 pistols before mid 1943 had the serials stamped on before finishing.  Early 1911 Colts up to about serial 7500 had their serials stamped after the finish was applied.  This was about the same time that the serial number location was moved to below the trigger.   Examining the markings will help determine if the pistol has been refinished, and it will certainly help to determine if the markings are original or counterfeit.  However a thorough knowledge of what the markings are supposed to look like on any specific pistol is generally necessary.  Markings that were applied before finishing will usually have all traces removed of the ridges created when the stamping die displaces metal. Often the ridges are hard to see.  Another clue, especially on blued pistols, is around the stamps where metal is displaced, the finish will often flake off in microscopic chips that will leave a white shadow appearance around the letters.  If the pistol is blued after these stamps, the micro flaking is highly unlikely.  Only by studying lots of pistols will one know what he is looking at, and that is getting to be more and more difficult. Was the stamp before or after finish. These will be indicated in the descriptions below. These marks will have a white or burnished appearance. Also remember that when metal is stamped it is pushed a side and will create a ridge. A powerful magnifying glass is essential to see the ridges and the detail around them.  If the ridge is absent and it should be there, The pistol most likely has been refinished. Refinished guns are worth much less then guns with the original finish.

Markings that are applied after finish are Arsenal Inspectors marks, sometimes firing proofs, and the Ordinance Escutcheon (Cross Cannons).
Colts Patent dates
Click on examples below to see larger version)

1911  Slide Patent Dates: 1 to 84,000 approx. "Aug. 19, 1913" Added to slide patent date added at approx. S/N 83,856 

1914 through 1945  Slide Patent Dates:
to end of production  approx.

"Rampant Colt" details by serial number

Circled, rear located Rampant Colt: 1 to 20000 approx.

Non-circled, rear located Rampant Colt.
20,000 to 285,000 approx.

Non-circled, middle located Rampant Colt. 285,000 to end of production  approx.

Serial number placement (M1911 and M1911A1)

About Serial Number 1 to 4500
(Stylized numbers to about 4500)

4500 to 7500
(Prefix to underline 0, font changed to BLOCK)

7501 to end of production
(Moved to behind slide stop hole)

Colt SN 710001 to about 1139xxx)
Colts between serial number 710001 and about 1139XXX have the serial number also underneath the firing pin stop plate.  
"United States Property" mark location

From Serial Number 1
to about 510000

From Serial Number about 500000
to end of production
Ithaca slide markings

The "Model of 1911 A1 U.S. ARMY" marking on the right side of the slide is normally found in the range from 906000 to 916404.

Remington Rand serial number variations
RR halted production in 1943, When they resumed production the line from under the "O" in  "NO" in front of the serial number was removed (see IMAGE above). This transition started at approximately 955000. (Top pre 955000, Bottom post 955000)
Remington Rand slide markings variations
Type 1 Slide: Observed from 916405 to approximately 955000 Type 2 Slide: Observed from approximately 927000 to about 1015000 Type 3 Slide: Observed from approximately 980000 to end of production. RR legend is shorter then the slide stop.
US & S "P" proof  markings

 The proof was absent to about 1,060,000 (ref Charles Clawson). From about 1060100 to 1082000, the P proof was applied at the left edge of the slide and on the frame. From about 1082000 to the end of production the P was placed centered in front of the rear sight and on the frame.  See example below SN range 105xxxx. On the EXP US&S pistols the ones that I have observed have a P on the the slide but not receiver. There is no Inspectors cartouche on the ESP marked pistols.

US&S absent proof marks

Notice P on this US&S slide is off center and located in lower left of this image, this is not uncommon. (Click on image for larger version).
Listing of known slide and frame/receiver markings (not complete)

AA: Augusta Arsenal. Found on the receivers of guns rebuilt or inspected at the arsenal. 
RIA: Rock Island Arsenal. Found on the receivers of guns rebuilt or inspected at the arsenal.
SA: Springfield Arsenal Rebuild Stamp 
ANAD/AN: Anniston Army Depot (Anniston, Alabama) observed with a date stamp following it (MM YY) in 1975
P: Can be found on top of slides on WWII A1s as well as on the Barrel and Frame below the clip (magazine) release.
United States Property: This stamp is found on the frame and slides of 1911s manufactured for and owned by the US armed forces. In most cases a gun with the property stamp will not have a "c" in the serial number.
S: located after finish by the disconnector on top of the frame indicates field service.
G: Located on top of frame by disconnector indicates gun was made to fill a Government contract. Stamped before the finish is applied.
H or H:  Provisional acceptance mark. Located on top of frame by disconnector indicates gun inspected by Ordinance Inspector. Stamped before finish applied. Francis L. Hosmer used this stamp on Colts 1911s and M1917 revolvers from 1911 to 1919.  Also found on barrels and slides.

Inspectors cartouche and Arsenal rebuild stamp examples

1942 Colt WB Example

1912 Colt WGP Example

1911AASavageBB.jpg (68699 bytes)
Augusta Arsenal 
Rebuild Stamp

Inspection initials found on 1911/1911A1s;
located under the slide stop on the left side of the gun

WGP Monogram: Walter G. Penfield, Major Colt S/N 1-101,500
GHS Monogram:
Gilbert H. Stewart. Found on Colt M1911s SN 101,500 to 230,000, M1907, M1917, M1903, and M1 rifles at different periods.
JMG Monogram: J.M. Gilbert found on Colt 1911s from 1917 to 1918 SN 230,001 to 302,000.
Eagle/Number: This replaced the personalized monograms about S/N 300,000 to end of WWI production (1919)

FJA: Frank J. Atwood. Found on Remington Rand and Ithaca 1911A1s (entire production).
EEC: Edmund E. Chapman Remington UMC S/N 1-21676
WTG: Walter T Gorton Colt S/N 700,000-710,000
CSR: Charles S Reed Colt S/N 717,282-723,000
RS: Robert Sears Colt S/N 723,000 to 750,500
WB: Waldemar Broberg Colt S/N 750,500 to 861,000
GHD: Guy H. Drewry Colt S/N 845,000 to 2,360,600
JSB: John S. Begley, very late 1945 Colt 1911 A1  to end of WWII production (1945-Very rare)

Arsenal Inspectors from Rock Island:

EB: Elmer Bjerke was promoted on January 6th, 1947 to Forman of small arms inspection. He was responsible for the final inspection of new and overhauled small arms. He served in that capacity until 1958. All small arms inspected under his supervision bear the markings "RIA" for Rock Island Arsenal and "EB" for Elmer Bjerke.
FK: Frank Krack was Assistant Foreman of the Inspection Division at RIA from September 17, 1941 until he retired on July 19th, 1946.  During that period all small arms inspected under his supervision would be stamped with his initials "FK" as well as those of the Rock Island Arsenal "RIA".

Click here to see common exterior markings examples

Parkerized/blued bullet feed ramp finish

Bullet feed ramps where blued in receivers to serial number 710,000, then at SN 710,001 they where machined after the receiver was blued or parkerized, leaving this area of the gun in the white and unfinished. This area should show machine marks and not be polished. In mid-1944 Colts bullet feed ramps where parkerized, this began at approximately SN 1700000.

Return to ID page

Rev 1.1c