Download PDF
March 2017-A
International
Business Machine (I.B.M.) Serial Number 3937627
This
IBM was a DCM gun originally purchased from the LetterKenny Army Depot in
Chambersburg, Pa. The receipt is shown
below and yes, it was sold for $20.
The
oval cut stock is marked LW-B (Lumb Woodworking Co Inc. of Poughkeepsie, NY) in the sling well with
the expected cartouche.
View of the barreled action including the trigger housing
and slide. Note the 26 ½ coil hammer
spring used in all I.B.M. carbines.
The type 1 rear sight is marked GE-Q and S on the other
side (the leaf is unmarked). GE-Q sights were made by Gerrand Co. of Chicago Illinois for Quality Hardware. They
have been reported on other IBM carbines but no documentation exist of a
lateral transfer between Quality Hardware and IBM. The rear sight
staking and sight pin staking is also shown.
Below is an overhead view of the
rear sight. Note the different types of dovetail staking on the left and
right side.
The receiver ring marked U.S
CARBINE CAL. .30 MI as shown below. Note the single staking
on the gas piston screw.
A close up of
the wrist (marked with W) and stock nose. Numerous original appearing, late IBM carbines were reported with a single letter stamped on the wrist. See CCNL 345 for
for
more information. The reason for the letters is unknown. Could they be
inspector marks? Perhaps they are inspector marks from the LetterKenny
or other depots? More information is needed. Collectors, please report
your IBM carbines to the club. The type 2 band has four weld scars. The P proof mark is also shown; note how close it is to the nose of the stock.
The recoil plate is marked PR-B (Parker Manufacturing Co. of Worcester Ma.) and is common on original carbines. The recoil plate
screw is of the late type.
The handguard is also marked LW-B (Lumb Woodworking Co Inc. of Poughkeepsie, NY). The oiler is marked IS for International Silver.
Note
the increased dwell on the AOB (Auto Ordnance of Bridgeport, Conn.) marked slide (see
CCNL 363). It appears many late IBM carbines have slides with increased dwell,
but no 7160091 number stamp. Also note the double stamps slide, in this
case stamped EE. Could double stamped slides denote increased
dwell? More research is needed.
The trigger housing is marked BE-B on the right side and is of the
braised type.
The trigger housing contains the following parts: Sear marked SW-B (
Star Watch Case Co. of Ludington, Mich.
)
, magazine catch marked
PR-B (Parker Mfg. Co. - Parker Wire Goods Co. of Worcester, Mass.)
, safety marked
EPB (Eaton Pond Co. of Springfield, Mass.
),Trigger marked PD B (Paradise Mach. Co. of West New York, NJ) and the hammer is marked AMB (Art Metal Works of Newark, N.J.).
The round bolt
is marked AOB (Auto Ordnance of Bridgepost, Conn.)
upside down on the right lug and an H
is stamped on the left. Note the type 3 firing pin and extractor.
Top view and close up of trigger
housing including single hammer strike mark and type 2 sear marked SW-B (Star Watch Case Co. of Ludington, Mich.).
IBM Barrel Proof Mark
A close up view of the IBM Barrel Proof mark. It appears to be
sideways. If others have serial numbers in this range, please report the
orientation of the P mark.
Multiple views of the I.B.M. SI B (Simpro Mfg. Co. of Newark N.J.)
front
sight and undated I.B.M. Corp barrel. Undated barrels have been
reported in the 3.79-3.96 range. Note the front sight key retention is
held in place by the milled notch also called the "hacksaw" cut. The
barrel crown is of the rounded type. Sometime during production, the way
barrel crowns were finished changed. Early barrel have a flat crown,
later ones rounded (CCNL 345).
Side views of the SI B front sight. Note the bluing and indentations on either side of the pin.
The type 2
barrel band has a single slash \ mark. Type 2 barrel bands on IBM's have been reported as unmarked, /, \ and //. Close up of the 4 weld scars type 2 barrel band.
The butt plate
is also shown. Two type of butt plates have been observed, type A (CCNL 329-4) and type B (CCNL 94-5). This butt plate is the type A "step" pattern.
Data Sheet
Thanks to owner
of this fine example of a late IBM carbine, Steve Manning.
Newsman2
Copyright:
The Carbine Collector’s Club©
http://www.uscarbinecal30.com/forum/