The U.S. Caliber .30 Carbines, Model M1A1

The U.S. Carbine Caliber .30

Model M1A1



M1E7 & T3



Right click on the image to view the model


Not long after the adoption of the U.S. Caliber .30 Carbine, Model M1, the need for a shorter version for use by paratroopers became evident. Early in 1942 U.S. Army Ordnance issued a request for submissions of designs for a shorter version utilizing a folding or collapsible stock. The Inland Division of General Motors submitted their first drawings for such a design during March 1942. Submissions by two other sources were found to be unacceptable. Revised Inland drawings were recommended for standardization as the Model M1A1 on 29 Apr 1942. The design was approved 12 May 1942. A patent application for the design was submitted 05 Aug 1942 and granted Patent# 2,405,758 13 Aug 1946.

The Inland design was simply a side-folding stock any carbine action could be placed into, in lieu of the full length stock of the Model M1 Carbine. The markings on the carbine receiver remained the same as those of the Model M1. No markings identifying the Model M1 from the Model M1A1 were added or changed anywhere on the carbine or its parts. ALL Model M1A1 Carbines made during WWII were carbine actions manufactured by Inland and placed into M1A1 stocks manufactured by Inland's subcontractors.

U.S. Carbine Caliber .30
Model M1A1

    Number of Parts*
Early: 79-81
Late: 78-79
    Barrel Length
    Sight Radius
21.5" @ 100 yards
    Overall Length
    Overall Length-stock folded
6.19 lbs
    Trigger Pull
4.5-7 lbs
    Stock Material WWII
semi-automatic only
*number of parts varied as minor changes were implemented and do not include a
complete breakdown of the rear sight and barrel band
Data extracted from
TM 9-1276 Cal. .30 Carbines M1, M1A1, M2, M3, U.S. Government Printing Office, 1953
(paragraph 6, pages 8 & 9)


During the ongoing production of the Model M1 Carbines, M1A1 carbines were made by placing a complete M1 action into an M1A1 folding stock instead of the regular M1 stock. Serial numbers were whatever Inland serial numbers reached the assembly point at the time the stock was added. Whereas the features of the carbines that went into the stocks varied significantly over time and are still a subject open to some degree of debate, the M1A1 stocks were made in far fewer numbers with far fewer variations during a shorter period of time.

This section will focus on the chronology of M1A1 stock production with a general description of the carbines placed within the stock variations. The individual stock parts are described in further detail in the Parts Section below.

The manufacture of M1A1 stocks can be divided into three basic time periods with
the first three producing M1A1 stocks that were predictably consistent.

  Inland's 1st Production Run:   November 1942 thru October 1943*
  Inland's 2nd Production Run:   May thru December 1944*
  Springfield Armory:   January 1945-1946

* Documents from Overton, Inland and U.S. Army Ordnance have conflicted with one another in regards to monthly M1A1 production and deliveries during WWII. The months and quantities presented on this page are best estimates based on reviews and evaluations of all available documents, interviews and experiences.

Inland's 1st Production Run

November 1942 thru October 1943

Inland subcontracted S.E. Overton of South Haven, MI, for the manufacture of all of their M1A1 stocks. For the first run, Overton manufactured the forestock and grip. Royal Typewriter Inc. of Hartford, CT, was subcontracted to manufacture all of the hardware, receive the wood components from Overton, then assemble and return the completed stocks to Overton. Rivets used on the first run were semi-tubular brass. The face of the rivet was often darkened with paint.

Overton inspected the finished stocks and forwarded them on to Inland. Ordnance acceptance marks in the form of the Ordnance crossed cannons were not added until after the stock was added to the carbine and the completed carbine passed a final Ordnance inspection. As with other carbine parts, a percentage of M1A1 stocks and parts were produced as replacements. These would not have had the Ordnance crossed cannons of the first production run.

Forestock:S.E. OvertonWalnut Highwood; OI stamped inside stock at rear of slide opening
Hand Grip:S.E. OvertonWalnut; OI stamped in bottom of grip
Hardware:Royal Typewriter 
Final Assembly:Royal Typewriter 
Final Inspection:S.E. Overton 
M1A1 Carbine Assembly:Inland Mfg. 
Test Fire ProofInland Mfg.a large circled P on rear of forestock
(discontinued during the latter part of 1st run)
Ordnance Acceptance
Inspectors at Inland Mfg.Ordnance cannons stamped on bottom of grip

Serial numbers of the Inland M1 carbine actions made during this period ranged from 70,000 - 950,000, and many of these actions were put into M1A1 stocks. Consistent features of the carbines in this range included a two-rivet handguard, narrow barrel band, flip rear sight, and push-button safety.

Inland's 2nd Production Run

May 1944 thru December 1944

The M1A1 stocks and parts left over from the first run at S.E. Overton and Royal Typewriter were used and intermingled with stocks and parts manufactured during the second production run until the inventory of the earlier parts ran out. Again, Overton manufactured the forestock. Initially Overton also made the hand grips but due to their workload and the complexity of manufacturing the hand grip, Overton subcontracted the J.S. Richardson Companies of Sheboygan Falls, WI, to manufacture the hand grip.

Poor quality control at Royal Typewriter prompted Overton to cancel their contract by May 1944. Overton purchased all of Royal Typewriter's equipment and inventory related to the M1A1 stock and relocated it to the Overton facility in Michigan. Royal Typewriter's inventory was sufficient to sustain the needs of Overton until the end of production, although Overton had to spend time and money to insure that the items manufactured by Royal Typewriter met Ordnance standards. Overton handled final assembly and inspection of the M1A1 stocks.

Rivets used during this time period were brass and later steel. Both were semi-tubular and were rolled over the plate on the inside. A few solid steel rivets have been observed. Brass rivets were often darkened with paint, and steel rivets were Parkerized.

Overton inspected the finished stocks and then forwarded them on to Inland. Ordnance approval marks in the form of the Ordnance crossed cannons were not added until after the stock was added to a carbine and the completed carbine passed a final Ordnance inspection. As with other carbine parts, a percentage of M1A1 stocks and parts were produced as replacements. These spares would not have had the Ordnance crossed cannons.

Forestock:S.E. Overton-Walnut Highwood; OI stamped inside stock at rear of slide opening
-Walnut Low Wood; OI stamped inside stock at rear of slide opening
Hand Grip:S.E. Overton
J.S. Richardson
-Walnut, OI on bottom of grip, Ordnance cannons on right side
-Walnut, RI above 3 on bottom of grip
Hardware:Royal Typewriter 
Final Assembly:S.E. Overton 
Final Inspection:S.E. Overton 
M1A1 Carbine Assembly:Inland Mfg. 
Ordnance Acceptance
Inspectors at Inland Mfg.Ordnance cannons stamped on right side of grip toward bottom

The serial numbers of the carbines placed within these stocks by Inland were mixed with Model M1 Carbine production generally in the 5,000,000 - 6,449,868 range. During this time Inland transitioned from:

  • the rear flip sight to the adjustable rear sights
  • the narrow barrel band to the wide barrel band and eventually to the barrel band with bayonet lug
  • the two rivet handguard to the 4 rivet handguard
  • the flat bolt to the round bolt
  • the late cam cut for the type V slide (marked 7160091 on bottom)

The last shipment of M1A1 stocks made by Overton (4,529) was shipped to Inland in January 1945, a month after Inland had completed it's second run of M1A1 Carbines (December 1944).


Model M1A1 Carbine
    WWII Production    

Inland Manufacturing

  1st Run 2nd Run
  Nov 1942 - Oct 1943 May - Dec 1944
1942 4,300 -
1943 66,648 -
1944 - 69,052
1945 - -
Sub Totals 70,948 69,052
Totals 140,000
 Source: "AGS Carbine History" by Smith & Davis,
March 25, 1938 to July 1, 1944.

Please keep in mind a number of reliable sources
do not agree with these months and quantities.

January 1945 thru 1946

With the completion of their M1A1 parts contracts, in November 1944 J.S. Richardson sold 8,000 M1A1 grips to Springfield Armory. In December 1944 J.S. Richardson sold all of their M1A1 tooling and custom machinery to Springfield Armory. Since Inland completed their second run production of the M1A1 in December 1944, it's likely the additional M1A1 stocks and parts at Overton and Inland were at some point also forwarded to Springfield Armory.

The M1 Carbine, A Revolution in Gunstocking, a book by Grafton & Barbara Cook, states that Springfield Armory manufactured 3,535 M1A1 stocks in 1945 and 3,773 in 1946 with no M1A1 stocks produced thereafter.

Springfield Armory production records found by Larry Ruth for the period January-June 1945 included the following M1A1 parts:

  • 34,160 hand grips
  • 93,000 locking springs
  • 9,000 hinge screws
  • 3,500 buttplate springs
  • 2,535 M1A1 stocks assembled

Richardson contour grip mfg
by Springfield Armory
1945-1946 only

Due to texture of the wood, SA on the bottom
of grip is often difficult to see.
Sometimes only the S can be seen

During WWII the M1A1 stocks and parts in the possession of Springfield Armory, whether made by Springfield or another manufacturer, were for use as replacements. No information has been found as to how many of these parts were actually placed on carbines prior to the end of WWII, or as to whether any of these carbines with replaced parts were used late in the war. A number of authors have concluded that these parts were used post-WWII only. Also, some thought no barrel bands with bayonet lugs or M2 Carbines were used during WWII. Evidence has been found to prove both saw limited use in combat in 1945.

Inspect and Rebuild operations by or under the direction of U.S. Army Ordnance that included Springfield Armory will be covered in the next section below.

One of the functions carried out by personnel at Springfield Armory was the packaging/preservation of replacement parts for the carbines. Packages with these parts have been dwindling over time but are still in existence well into the 21st Century. One such parcel was located containing seven packs of eight M1A1 hand grips each. The packs were dated January 20, 1945 thru April 27, 1945. Markings on the bottom of each grip were either SA or P-SC. The grips marked P-SC had been noted prior but these packs were the first to establish their authenticity as genuine M1A1 grips. While no evidence has yet to be located to identify who manufactured the grips.


M1A1 Stocks
Total Production

  S.E. Overton Springfield Armory
1942 31,885 -
1943 70,667 -
1944 132,666 -
1945 4,529 3,535
1946 - 3,773
Sub Totals *239,747 7,308
Total *247,055
Source: The M1 Carbine, A Revolution in Gunstocking by Grafton & Barbara Cook
(* refer narrative that follows)

No evidence has been found as to whether Springfield Armory manufactured or contracted someone else to manufacture the forestocks they used in the assembly of M1A1 stocks. Ordnance contracts for parts routinely included a percentage of extras to be furnished for use as replacements. Thus, it would seem that Inland would have furnished some spare M1A1 stocks, in addition to the 140,000 they used in the assembly of their M1A1 carbines. Records at Overton indicated they manufactured 239,747 M1A1 stocks, which is significantly more than used by Inland and the normal percentages to be furnished as replacements.

While it is not known whether Ordnance contracted Overton to produce a large quantity of extras for use by Springfield Armory, it is obvious that the quantities manufactured by S.E. Overton were more than sufficient to meet the total needed for Inland's M1A1 carbines, a percentage for use as replacement parts, and the M1A1 stocks assembled by Springfield Armory. The only manufacture marks observed on forestocks are OI (IO), indicating they were manufactured by Overton for Inland. Therefore, it seems possible that Ordnance might have contracted with Inland to furnish a large quantity of M1A1 stocks in addition to the standard percentage of spare parts.

Early plans for Springfield Armory to take over the carbine program initially included plans for Springfield Armory to manufacture carbines. As the war and time progressed, the plans to manufacture carbines were dropped.

It is possible that some or all of the spare parts manufactured for use as replacements might have been assembled into complete M1A1 stocks by Springfield or other facilities.

U.S. Ordnance
Inspect & Rebuild Operations

Inspect and repair operations were ongoing throughout WWII and afterwards by Ordnance field personnel. Repair operations in the field were limited to parts on hand. Field rebuild operations were limited in scope and also limited by the availability of parts.

Massive Inspect and Rebuild Operations under the management of U.S. Army Ordnance are known to have occurred post WWII and again at some facilities after the War in Korea. The exact dates of these operations at the various stateside facilities are not known. Ordnance contracted for Inspect and Rebuild operations to be done outside the United States as early as June 6, 1945 at Fabrique Nationale in Belgium, where it continued until June 23, 1946. Howa Machinery in Nagoya, Japan was also contracted from approximately 1947-1949.

Workers at Fabrique Nationale during Inspect & Rebuild Operations 1945-1946

Ordnance directions for these operations called for complete disassembly of each carbine (M1A1 stocks included), after which the parts were forwarded to inspection stations specific to the parts. Some parts were upgraded, some passed inspection, some were replaced, and some were refinished. Rotary safeties, adjustable rear sights, and barrel bands with bayonet lugs were standard Ordnance upgrades for all carbines.

When the parts met Ordnance specifications they were forwarded to a reassembly station from which carbines were rebuilt without regard as to who manufactured which part. Carbines were reassembled into M1A1 stocks without regard as to who originally made the receivers.

The degree to which this happened varied, depending on a number of factors that included the availability of replacement parts and deadlines that were sometimes altered to expedite the operations. Many M1A1 carbines that went into these operations came out with M1 stocks due to a lack of replacement parts and because there was no attempt to put an action into its original stock type.

After a carbine was completely re-assembled and passed a final Ordnance inspection, the stocks were stamped with the initials of the facility that did the inspection, whether it was a stateside arsenal, armory, or a contracted facility. On the M1A1's these initials normally appear on the left side of the forestock above the hand grip, but they may be found on the right side of the forestock above the hand grip. If the letter P appears anywhere on the hand grip, it was added at the time of the final Ordnance inspection after an Inspection and Rebuild operation. The P may be within a circle or box. (refer to the page on Post WWII Ordnance Ops for further details, facilities and their letter designations)

Companies outside the continental United States contracted for Ordnance Inspect and Rebuild operations were prohibited from placing any marks on the small arms they serviced.

Rock Island Arsenal rebuild with
initials of Ordnance District Commander

Augusta Arsenal rebuild
(3rd letter varied)

Rebuild Proof Mark
(anywhere on grip, any size, circled, boxed or otherwise)

Rebuild markings and the arsenals and armories they represent are covered in further detail
on the page devoted to Post WWII Ordnance Operations.

Forestock*:AnyWalnut or Birch; Highwood, Low wood, or Highwood cut to low wood may or may not have OI inside stock at rear of cut for slide
Hand Grip:AnyWalnut, Birch or Mahogany
OI or RI over 3, SA, P-SC, or unmarked on bottom of grip
Final Assembly:U.S. Ordnance facility 
Final Inspection:U.S. Ordnance 
Ordnance Acceptance
Ordnance Inspectors-Armory/Arsenal letters on left rear of forestock
-any P in any form anywhere on the handgrip
* Original GI M1A1 stocks did not have a cutout for the M2 selector lever

Rivets used during the Inspect and Rebuild operations were brass. Some were marked 7/4 on their face. The rivets were semi-tubular and rolled over the plate on the inside. At least one facility contracted by Ordnance outside the USA (FN) is known to have used rivets obtained locally.

And Beyond ...

U.S. Forces

During and after WWII, any M1A1 needing service or repair at any point in time may have been serviced by U.S. Ordnance field personnel anywhere in the world. The parts used depended on the availability of replacement parts. Absent replacement parts, the carbine was simply placed into a full sized stock as a Model M1 or possibly a Model M2 conversion.

While the M1A1 was not built as a select-fire carbine, GI's have long been known for a variety of field expedient conversions of various types. Specialized units with special needs had the ability to modify weapons to meet their needs. During the Korean War, a number of M1A1's were converted to select fire capability and unofficially referred to as M2A1's.

Other Nations

During WWII U.S. M1A1 Carbines were supplied to allies under the Lend-Lease Program and dropped to resistance fighters in Europe by the Office of Strategic Services (O.S.S.) and their British counterpart, the Special Operations Executive (S.O.E.). Post WWII the Military Assistance Program provided M1, M1A1 and M2 Carbines to many nations as military assistance. Replacement parts were often included. A number of nations utilized local sources for replacement parts (Greece is known to have made forestocks and used post-war M1A1 buttplates having the part number followed by a circled P...see parts below).

Police Agencies - U.S. & Abroad

Police departments throughout the world have used M1A1's, including the Detroit Police Department during the 1960's. Replacement parts were sometimes obtained by cannibalizing existing stocks.

Commercial or Personal Reconstructions, Reproductions, Replicas, and outright Fraud

The Model M1A1 Carbine has been one of the most highly sought U.S. Carbines since WWII. The limited number of originals manufactured, their attrition due to losses and use during and since WWII, and their high demand by many collectors willing to pay top dollar have made most unaffordable to the average shooter.

Since the mid 1950's a number of private commercial companies have manufactured a variety of replacement parts that appear similar to the originals. Several companies have produced after-market M1A1 stocks that are now widely available. A number of companies have produced commercial versions of the M1A1 Carbine, including Auto-Ordnance (Kahr Arms), Fulton Armory and James River Armory (under the trade name "RockOla Firearms"). Additional companies have produced M1A1 airsoft and/or air rifles, and some have produced non-firing replica M1A1 Carbines (Denix of Spain).

Authentic vs. Reconstructions

Reconstructions using original parts with after market parts have become common. Some are sold as what they are, and some are represented as all authentic (intentionally or unintentionally). Fortunately, the original M1A1 stocks have a number of unique features that have not been replicated accurately. These features are included in the parts section that follows. Buyers would do well to get to know these features along with historical data provided above.

The Parts


Highwood Walnut used during Inland's 1st production run and at the beginning of their 2nd
production run. Some had the highwood cut to the low wood at some point after leaving
Inland. May or may not have the large circled P on the rear of forestock used as a
proof test fire mark. Arsenal letters, usually on left rear, indicate the stock was
on a carbine subjected to a stateside U.S. Ordnance inspect and rebuild program.

Low wood Walnut used during Inland's 2nd production run. Arsenal letters, usually on left rear,
indicate the stock was on a carbine subjected to a stateside U.S. Ordnance inspect and rebuild program.

Inset for tubular stock was milled, leaving pronounced edges as opposed to smooth curves (white arrows).
Wear from contact with the buttplate (black arrow)

Note the shape/contour of the rear of the forestock

ALL forestocks manufactured during WWII were manufactured by S.E. Overton for Inland
and marked OI (IO) inside at rear of slide channel cut, just forward of cross support.

Hand Grips

Manufactured by
S.E. Overton
Manufactured by J.S. Richardson
& Springfield Armory
Note both have relatively straight backs

Bottom of hand grips were often rough and unfinished making markings difficult to see.
This area was often smoothed by repeated folding of the tubular stock, removing part or all of any markings.

OI  S.E. Overton for the Inland Division of General Motorswalnut
  J.S. Richardson for the Inland Division of General Motorswalnut
S or SA  Springfield Armory 1945-1946walnut & birch
P-SC  replacement grips *birch
(none)  replacement gripswalnut & birch
* manufactured during WWII in 1945 and possibly post WWII. Manufacturer MAY have been Frank Purcell Walnut Lumber of Kansas City, KS, a WWII subcontractor for stock manufacturer Sprague & Carlton of Keene, NH.

Information from The M1 Carbine, A Revolution in Gunstocking by Grafton & Barbara Cook indicates some late manufactured grips were made from mahogany.

U.S. Ordnance Acceptance Marks were for completely assembled M1A1 Carbines that passed final inspection. Replacement parts, M1A1 stocks absent a carbine, and M1A1 Carbines assembled that were not inspected by U.S. Ordnance did not receive these marks.

Ordnance Acceptance Marks
MarkLocationTime Period
  Small Crossed Cannons  Bottom of Handgrip  Inland 1st Production run: Nov 1942 thru Oct 1943
  Medium Crossed Cannons  Right side of Handgrip  Inland 2nd Production run: May thru Dec 1944
  P alone, encircled or within square  Anywhere on Handgrip  Rebuild proof mark Post WWII

Manufacture markings and Ordnance crossed cannons have intentionally been omitted from this web page. Dies for replicating these marks are widely available but authentic parts had variations in fonts, size, location, etc. that we do not wish to share to educate those who seek to accurately replicate them. For questions regarding authentic manufacturer and Ordnance marks please post your queries with pictures on one of the Carbine Discussion Forums indicated at the bottom of this page.

Tubular Bar Extensions, Upper & Lower

The bar extensions were constructed using .312" diameter hollow metal tubing into which the solid steel Lock and Hinge were welded (not brazed) onto the ends that attached to the Hinge Screw. The Tubing, Lock, Hinge and their weld were then case hardened and parkerized.

The top extension tube includes a detent (arrow) for proper positioning of the Cheek Rest Plates.

The general shape and size of the weld marks where the tubes were attached to the solid
metal Lock and Hinge pieces are consistent in appearance on all GI bar extensions.
The color of the parkerized welds should match the tubes and end pieces.

Cheek Rest Plate & Cheek Rest Cover Retaining Plate

Together the Cheek Rest Plate and Cheek Rest Cover Retaining Plate served as a mount for the leather cheek piece and strengthened the stock tubing extension. The plates were placed over either side of the center of the tubing extension. The leather cheek piece was placed over the Cheek Rest Plate. Rivets were placed through holes in the leather, Cheek Rest Plate and Cheek Rest Cover Retaining Plate then peened to secure the three pieces to the tubing extension.

Neither plate has a manufacturers mark. Both were parkerized the same as the extension tubes.

Cheek Rest Plate
Cheek Rest Cover Retaining Plate
The black arrow indicates the location of the nub that mates to the indent in the upper tube for proper
placement of the plates. The width and height of the openings to either side of the oiler retention piece
(white arrows) are worth examination. They're size was consistent throughout production. The width and
height of these openings can vary with reproductions.

Leather Cheekpiece & Rivets

The Leather Cheekpiece was constructed from smooth or very lightly textured cowhide having a thickness of 2-3 oz. (1/32"-3/64"). The leather was dyed medium to dark brown or black. The leather covered the entire exterior surface of the Cheek Rest Plate wrapping over its edges. The leather was secured by pressure exerted on the edges of the leather when the Cheek Rest Cover Retaining Plate was secured to the Cheek Rest Plate with rivets. The fit of the leather between the plates left no visible gaps, folds or binding.

A unique feature of all M1A1 cheek rests was the head of each rivet was inset into the leather and sat flush with the surface of the leather. None of the head protruded beyond the surface of the leather.

Rivets were automotive brake shoe rivets with a solid head having a diameter of 3/8" that tapered sharply to a shank diameter of .191"-.010". The overall length of the rivets was 9/32". The majority of rivets used on the M1A1's were semi-tubular having a hole 3/16" deep in the rear of the shank. Solid rivets have been occasionally observed but were rare. When the shank of each rivet was peened it rolled over the rivet hole forming the shape of a donut, not flattened. Semi-tubular rivets have a donut "hole" that is absent with solid rivets.

Rivets during the period of Inland's first production run were brass. Brass rivets were common throughout production. During Inland's second production run steel rivets were also used. The heads of brass rivets were commonly painted black, steel rivets were parkerized. The black paint was commonly obliterated with use and time.

Brass rivets marked 7/4 on the head were used during inspect and rebuild operations. The 7 indicated a head diameter of 3/8", the 4 indicates an overall shank length of 4/16".



Replacement Rivets

At any point in the life of an M1A1 stock, if the M1A1 buttplate, metal extension bar(s) or leather cheekpiece
required replacement it was necessary to remove the rivets and cheek plates. Reassembly required the use of new rivets.

Recoil Plate

The M1A1 Recoil Plate was machined from solid steel and parkerized. It has no manufacturers mark.


Recoil Plate Cover

The Recoil Plate Cover was made from sheet metal and parkerized. It has no manufacturers mark.

Recoil Plate with Recoil Plate Cover

Mounted on an M1A1 Carbine

Grip Screws

An early wood grip screw that saw limited use was approximately 2.125" in length with threads .870" in length. This screw extended only .870" into the handgrip. When pressure was applied to the handgrip it tended to crack due to lack of support.

The vast majority of wood grip screws were 2.75" in length with threads 1.80" in length. The threads engaged both the handgrip and forestock. The head diameter and angle of both wood screws matched the depth and angle of the hole in the top of the recoil plate so that the screw head sat flush with the top of the recoil plate with no lateral movement when the screw was fully inserted.

Hinge Screw

The Hinge Screw was 5.2" in length with a .50" in diameter head. The diameter and shape changed at various points along the screw to accommodate the various parts that fit onto the screw at various points along the shaft. The main shaft was .290" in diameter that was reduced to .250" in diameter 3.15" from the top for proper positioning of the Washer. Hinge Screws were parkerized and unmarked.


Washers were .505" in diameter and .062" thick. The center hole was .254" in diameter. They were unfinished and unmarked.

Locking Spring

The Locking Spring was 1.310" in overall unassembled length with 9 coils in a right hand twist having an outside diameter of .50". The wire was .076" thick providing approximately 93 lbs. of pressure when fully constricted. The ends were both squared and ground. They were unfinished and unmarked.

Hinge Screw Spacer

The Hinge Screw Spacer was 1.14-1.5" in length with an outside diameter of .31" and inside diameter of .25". It was hardened, parkerized and unmarked. The dimensions of this part mates to those of the Hinge Screw, Locking Spring and inside of the Lower Hinge Assembly. These parts are usually not interchangeable with their commercial equivalents.

Lower Hinge Assembly

The Lower Hinge Assembly was one unit assembled using three separate parts: the Lower Hinge Shell, Rear Sling Eyelet and Lower Hinge Nut. After assembly the group was parkerized and left unmarked. The manufacture of these three parts and the manner in which they were assembled to one another helps to identify them from their commercial counterparts.

The Rear Sling Eyelet was 1 11/32" wide and 3/32" thick. The eyelet opening
was 1 1/32" wide and 1/4" deep with slightly rounded inner edges.

The Lower Hinge Shell has two round indentations created
for the weld to the Rear Sling Eyelet. Two oval spot
weld marks can be seen opposite on the Rear Sling
Eyelet (see pic below).

Inside the Lower Hinge Shell the nut is countersunk on the inside to hold
the Hinge Screw Spacer. Note the angle of the walls on the inside
of the nut. Commercial replicas are absent this feature.

The Lower Hinge Nut has 2 short bullet shaped indentations that created protrusions
on the opposite side for the spot weld that joins the nut to the eyelet. Parallel to
the nut indentations you can see two oval spot weld marks where the eyelet was
welded to the lower hinge shell. Non GI Lower Hinge Assemblies are absent the
indentations. A few unscrupulous people have attempted to replicate these notches.

Lower Hinge Screw

The Lower Hinge Screw of the M1A1 stock is the buttplate screw of the M1/M2 stocks.

Buttplate Spring

The Buttplate Spring consists of two coiled ends approximately .38" in diameter with each having a length of approximately .30". At the outer end of each coil the wire made a 70 degree turn stopping at the outer diameter of the coil. These ends engaged slots in the tubes that held the spring in place. Between the two coils the .036 diameter wire was straightened approximately .66" to engage the buttplate to place tension on the spring. The springs were parkerized. Replacement springs were unfinished.

Over time the spring and coils commonly stretched beyond their original width. Replacing the spring requires removal of the rivets and leather cheekpiece.


The M1A1 Buttplate was cast using a sand/resin squeeze mold having multiple cavities to produce 12 buttplates at a time. All markings were part of the mold and imprinted during the casting process. The buttplates these molds produced have a sandy texture on the inside often making the markings difficult to identify.

The markings started with the part number B257614, followed by what appears to be a spoked wheel, then a number from 1-12 (indicating the mold position). The spoked wheel identifies the foundry as Saginaw Malleable Iron in Saginaw, Michigan. All authentic WWII M1A1 buttplates were cast by this foundry.

Part number B257614, Foundry symbol, number indicating the mold position (1-12)

The M1A1 buttplate below has been found on some of the M1A1's returned to the U.S. Army by Greece. Greece is known to have arranged for the production of replacement stocks for the M1A1. It is absent the sand texture consistent with the sand/resin mold and the number used to indicate the mold position. It indicates part number 6257614. The spoked wheel is absent and in its place is an encircled F.

Part number B257614 followed by encircled F

The B257614 on GI M1A1 buttplates during WWII was the U.S. Ordnance drawing and part number used under the U.S. Standard Nomenclature List (SNL). This inventory system was replaced with the U.S. Federal Stock Number (FSN) system in the 1950's. Under the FSN system the M1A1 buttplate designation became 6257614.

No documentation has been found to indicate who manufactured this buttplate. However, the encircled F was used by Ferro Machine Company, a subcontractor for Ford, on M1 Garand barrels manufactured circa 1956-57 as well as U.S. Carbine Flash Hiders and Recoil Checks manufactured sometime during the late 1950's and mid 1960's. It's possible U.S. Army Ordnance or the U.S. State Department contracted Ferro Machine Company to manufacture these M1A1 buttplates which they provided as military assistance or aid to Greece.

Should you have questions, assistance is available on our Discussion Forum.

The Discussion Forum also serves as a reference desk for the more advanced material that could easily overwhelm a website and is often subject to opinions that may vary
due to a lack of original documentation. A number of researchers and authors are present on the forums, helping others and seeking information for various research projects.

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