M1919 Piece Marks and Part Numbers 1936 to 1948
By Charles Brown

One thing that confounds some U.S. military weapons collectors are the markings found on parts; some applied at the behest of the Ordnance Department and some applied by the manufacturer. This article is intended to shed some light on why some parts are marked and many aren’t.

In 1902, the Ordnance Department began the practice of assigning “piece marks” to the component parts of Major Items. Most of the confusion starts right here. Even though each component part of a Major Item was assigned a “piece mark” very few, if any, of the pieces were actually marked with the piece mark. Piece marks were assigned for two reasons, to give a discrete identification to every part in short hand form and to aid in locating that part on the drawing used to fabricate the part.

The first piece marks were developed using the sheet number of the set of dimensioned drawings where the part appeared followed by an alpha character starting with A on each sheet and continuing up the alphabet as far as necessary to cover the parts shown on that sheet. If the design of the part was changed the revision number of the drawing that effected the change was shown as a numerical suffix to the piece mark.

The Major Item drawing sheets in use at the time were all the same size (29x40 inches) and depending on the size of the part and the scale in which it was being depicted, sometimes many parts could be shown on the same sheet. During WWI weapons produced by civilian manufacturers often had the manufacturer’s identification symbol imprinted on the parts. Depending on the weapon, the same manufacturer’s symbols could appear in different form. The Model of 1917 Browning water cooled machine guns parts produced by Colt had a C in a square, New England Westinghouse a W in a circle and Remington Arms used the R in a triangle while M1917 rifles produced by Remington used just the R, however, in both cases no piece marks were applied to the parts.

In 1922 The Ordnance Department adopted an entirely new system of drawing preparation, filing and nomenclature. The new system as applied to small arms used 5 different sized media for the drawings depending on the size of the part and the desired scale and only one part was to be shown on each drawing. Additionally, assemblies of parts received their own drawing. The drawing sizes in inches were:

A =8 1/2X14
B =12X20
C =18x30
D =24X40
E =40X required length

Every drawing of every part shown on the original Class and Division drawing sheets was redrawn on the new size sheets. Each size sheet started their numbering at 1. A1, B1 and so on. The numbers in each letter size were assigned in succession, which means drawings of the same letter size one number apart could be, and often were of totally unrelated items. The drawing numbers were assigned by the prints section of the Office of the Chief of Ordnance which kept a master file. If a particular part had an alternate design such as the elevating hand wheel for the M2 and M3 tripod T&E, it was assigned an alpha character suffix. This particular part, drawing B108211, had three alternate designs suffixed A, B, and C.

With the adoption of the letter prefix system identifying drawings, Ordnance continued the practice of assigning piece marks based on drawing numbers which changed every piece mark of every part. The redrawing of every part of every weapon was a monumental undertaking considering that theses drawings were all done by hand. In the case of the Model of 1917 machine gun the changeover to the new letter prefix drawings was not completed until June 1, 1931. Development of the air cooled M1919A4 included marking some of the parts with piece marks. All of this development occurred in government operated facilities principally; the Rock Island Arsenal and the drawings used to produce the component parts dictated the size and location of the markings to be applied. The proper Ordnance format for the drawing number and the piece mark derived from it was the letter size followed by number of the drawing without any dashes or spaces between the letter and the number.

Ordnance, like every other inscrutable bureaucracy, did not always understand and follow its own directives and many drawings had dashes and spaces incorrectly included between the letter prefix and the drawing number. Contractors manufacturing parts either misread the drawings or added dashes or spaces on their own hook or copied errors on the drawings provided to the die stamps and the same part became piece marked in a variety of formats often by the same manufacturer. There is no significance whatsoever to dashes, spaces or lack thereof between the letter prefix and the drawing numbers of piece marks applied to parts. The practice of noting changes to the part design by suffixing the piece mark with the number of the revision to the drawing that changed the part continued. To avoid corrupting the drawing number a dash was inserted between the end of the drawing number and the revision number. Not all of the revisions to the drawing changed the design of the part; in fact most revisions were administrative in nature. Many revisions merely cleaned up a messy drawing to improve legibility.

Even if the design were altered, that did not necessarily signal a change to the piece mark suffix. Changes to the piece mark suffix were decided on by the Office of the Chief of Ordnance sometimes after many minor changes had been made to the part design. As a general rule changes to the piece mark suffix did not make the part non interchangeable with earlier versions of the same part having the same drawing number/piece mark. If a new part was designed that was non interchangeable it received a new drawing number. Since the piece mark suffix is dependent on the drawing revision number which has a date certain it is possible to determine the approximate earliest date the part could have been produced providing you have the drawings or the drawing index card that show the actual date of the revision.

However, there is at least one, and likely several flies in this ointment. Since many small arms, especially the M1919s, were produced under contract and these contracts, like most other contracts, provided for changes. For change orders, the government representative, which in this case was the Ordnance District supervising the contract, was often left to negotiate the timing of the change to avoid additional expense. Sometimes the Ordnance Department bit the bullet and declared the changes to be mandatory immediately and paid the freight. Most often they didn’t. With the onset of WWII and the prospective use of contractors, Ordnance decided to develop a list of M1919 parts to be marked with piece marks and a uniform system of identifying the contractors.

Following the standard Ordnance policy of placing lists of parts and assemblies on B size drawings, drawing B169913 was produced. The earliest version of this drawing from January, 1941 only listed the parts to be marked and contained no manufacturers marking, it was not adopted. The list of manufactures included some very familiar names and some that had never before manufactured weapons. The list of M1919A4 manufacturers appears to be a generic list as only three of the listed manufacturers, Rock Island Arsenal, Buffalo Arms and Saginaw Steering Gear produced complete weapons and after 30 June 1943 only Saginaw was in regular production of M1919A4’s and later A6 models. However some of the others listed have produced component parts. January 1942 brought a change by Revision 1 to this drawing; apparently the original draftsman added periods following the initials of the manufacturer and Revision 1 removed them, however, the periods appear to have returned on Revision 9 which added Gellman Manufacturing Company to the list of manufacturers. This explains why some Saginaw parts are marked “S.G.” and others are marked “SG”. Originally it was thought by the author that the parts marked S.G. could have been produced at Saginaw’s Grand Rapids, MI plant, however, after the markings drawings were discovered that theory became much less credible.

Originally all of the listed parts were required to have either assembly or component drawing numbers and the manufacturer’s identification. This proved to be impractical because of the size and shape of some of the parts, such as the ejector, and the requirement for piece marks on some parts was dropped. As time passed Ordnance added items such as the bottom plate in January 1942 and in July, 1943 deleted the rear sight base spring and its alternate design.

The assignment of piece marks to assemblies followed no rhyme or reason. The bolt assembly consisting of the bolt and the recoil plate was marked with the assembly drawing number while the barrel extension assembly made up of the extension and the stud for the barrel plunger was piece marked with the drawing number of the barrel extension even though there was an assembly drawing. There are more than a few samples of hybrid markings on some bolt and extractor assemblies, most of which involve Westinghouse circle in W marked bolt assemblies also bearing B147299-BA markings.

Recoil plates, installed in bolt faces to prevent firing pin hole wear, were not in use prior to July of 1931 and New England Westinghouse was no longer in the machine gun business. Apparently, Buffalo Arms acquired original New England Westinghouse marked M1917 bolts lacking the recoil plates and reworked them into the then current version with the recoil plate. Most cast bottom plates, which were produced by Saginaw’s Malleable Iron Division, were not piece marked at all. This omission was likely caused by the fact that the cast bottom plates were produced from Saginaw’s own drawings with a note to obtain some dimensions from the Ordnance Department drawing for the machined type. The Saginaw drawing said nothing about marking the plate with the piece mark so it didn’t get marked. An alternate theory has been advanced that only bottom plates intended to be used as replacement parts were to be marked, however no textual evidence to that effect has presented itself so far. The biggest problem with this last theory is how the production line knew which bottom plates were to be used for production and which plates would be used as replacement parts.

Why the Detroit Ordnance District didn’t catch this lack of cast bottom plate marking and do something about it is not known. While the markings drawing specified which parts needed marking, the drawing of the part itself specified where and how the part was to be marked. It appears that the Ordnance District supervising production had great latitude in approving deviation from the prescribed location of the markings. The Ordnance Department also allowed manufacturers to mark parts not on the markings drawing and apply production codes and internal inspection markings. Buffalo Arms used a large number of sub-contractors to supply parts and apparently coded these suppliers with numbers applied to component parts of assemblies. They also applied their BA mark to many parts not shown on the markings drawing. Early Rock Island Arsenal produced M1919s had many parts such as rear sight base, front barrel bearing and plug, top cover, barrel jacket, back plate and various other parts marked and it is not presently known why this was done as there was no presently known requirement to do so.

Since the adoption of piece marks in 1902 they had been used by both the Industrial Service Division for production of the part and by Field Services for parts stocking and ordering purposes. In 1941 the Field Services Division began the use of IBM punch card machines for inventory control. The formatting for this new system was not set up to recognize alpha characters so Item Stock Numbers consisting of only numerals were assigned to each component part. The consequence of this was creating two systems of component parts and assemblies’ identification and the use of extensive cross reference lists. One can only speculate on the order of magnitude that the use of these lists increased errors. By 1943 the Chief of Ordnance had enough of this foolishness and directed the Engineering Administrative Section to develop a single system of identification that would serve as the drawing/piece mark/stock number. The result was to convert everything to an all numeral format: not something easily done in the midst of a world war. It was decided to dip the Ordnance toe in the water by applying the newly developed 7 digit system to any new part for a new Major Item or any new part for an existing Major Item. Additionally, the term “piece mark” was to be replaced by the words “part number.”

The block of numbers assigned to this task was 7000001 to 9999999. A system for “converting” all of the existing drawing/piece mark numbers was also developed that consisted of adding prefix numbers to the drawing number based on the drawing letter to prevent duplicating drawing/part numbers. This conversion worked as follows: the letter prefix was dropped from the drawing number and all A size drawings had 5000000 added to the remaining digits, B size 5500000, C size 6000000, D size 6500000 and E size 6900000. Even though the letter prefix was “dropped” it continued to be used because the drawings were filed according to size. Field Services also developed a conversion system of adding enough zeros as prefixes to the existing Item Code to get a 7 digit number which was now called Item Stock Number. Since the all digit stock number gave no indication of what the part was to be used on a four character prefix based on the Standard Nomenclature List classification code was added to the 7 digit drawing/stock/part number.

If a part was used in more than one SNL Classification Code it was assigned the first code where it appeared. Since many of the internal parts of the M1919’s, such as the bolt assembly, are common with the M1917A1, these parts were prefixed A005 while parts specific to the M1919s used the prefix A006. The early M1919A6 used the bi-pod leg assemblies of the M1918A2 BAR so these assemblies were assigned the prefix of A004 because the BAR is SNL classification A-4. It was understood by all parties involved that complete conversion to the new system would be postponed until after the war’s end.

All of the changes to naming conventions for drawings/parts/piece marks were so nearly incomprehensible even to experienced Ordnance engineers and draftsmen that in October of 1945, RIA felt compelled to produce a 12 page single spaced typewritten pamphlet titled HISTORY OF ORDNANCE DRAWING NUMBERS AND ORDNANCE PART NUMBERS.

This document is likely the best explanation of what transpired. In the case of the M1919s this conversion of existing drawings/part/stock number was finally accomplished in May of 1948. The existing parts inventory was relabeled, repackaged or over-packed with the new stock numbers. The Ordnance Department also began to develop better packaging methods, i.e. doing away with the old parts preservation system that relied on Cosmoline or grease in favor of dry packaging, which made the parts usable without spending half a day scrubbing preservatives off with gasoline and your toothbrush.

In addition to piece marks, the bolt assembly, barrel and barrel extension of the M1919 were required to undergo a proof test consisting of the firing of a HPT (high pressure test) cartridge. The finished weapon was also given a firing function test. Parts passing this test received, along with the complete weapon, were given the “P” (proof) stamp along with the Ordnance “flaming bomb” mark.

Manufacturers of complete weapons and parts were allowed to add additional letters, numbers and symbols for internal controls. While Ordnance allowed this practice they apparently did not keep any records of these markings and the meaning of these imprints is left to speculation and comparative analysis to determine their significance.

By May of 1948 all of the part and assembly drawings for the M1919’s had been re-drawn and re-numbered using the conversion scheme adopted in late 1943. However, because of the filing system used for the drawings, the letter size continued to be shown on the drawings, usually in a box adjacent to the drawing/part number, and was often erroneously imprinted on the part itself. This is very common on M1 rifle parts produced during and post Korea. M1919 parts production after May 1948, now back in the hands of RIA, were marked with the 7 digit part number/drawing number/stock number. This was not the end of the parts/stock numbering saga, the whole system underwent multiple changes starting with FIIN (Federal Item Identification Numbers and interim stock numbers for things like common hand tools and consumable cleaning/maintenance items such as bore cleaning patches, solvents and oils.

In July 1952, conversions to the FSN (Federal Stock Number) began and small arms parts that formerly started with the SNL based one letter 3 digit system became the prefix 1005 followed by the 7 digit drawing/part number. Finally in 1975, NSN (National Stock Numbers) were adopted expanding the 11 digit FSN to 13 digits by adding a two digit NATO country code.

This article first appeared in Small Arms Review SAW (October 2012)
and was posted online on August 31, 2012


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