Background

Barrel Group

Barrel	type 1	I.B.M. Corp. (no date)
Front Sight	type 2	PO-B (Prestole Division Detroit Harvester Co. for IBM)
Barrel Band	type 3	D inside diamond
Barrel Skirt
Slide	type IV	AOB & F (Auto Ordnance for IBM)

Barrel has P proofmark under the barrel band. Last 4 digits of receiver serial number stamped in right side of slide rail. Barrel band is parkerized.
No import mark (Canada).

Stock Group

Stock	type 3	SC-B (Sprague & Carleton for IBM)
Handguard	type 2	SC-B (Sprague & Carleton for IBM)
Buttplate		(IBM)

Stock has crossed cannon ordnance mark on right side of stock. Stock has the last 4 digits of the receiver serial number in the sling well, as does the handguard bottom side.

Receiver Group

Receiver	type 2	I.B.M. Corp., AO (Auto Ordnance) below s/n
Rear Sight	type 3	I.R.CO. 7160060 (International Register Co.)
Recoil Plate	type 3	PR-B (Parker Mfg. Co. for IBM)

Receivers for I.B.M. were subcontracted out for manufacture by Auto Ordnance. Receiver milled "Bavaria Municipal Police".

Bolt Group

Bolt	type 3	EM-B (Endicott Machine Co. for IBM)
Ejector
Extractor	type 3	IB (IBM)
Extractor Plunger
Firing Pin		BE-B (IBM)

Bolt is round, has usual last 4 digits of receiver serial number lightly electro-penciled in top of bolt.

Trigger Group

Trigger Housing	type 4	Q-TX (Triplex Corp. of America for Quality Hardware, used by IBM)
Trigger	type 2	PD-B (Paradise Machine Co. for IBM)
Sear	type 2	BI (IBM)
Hammer	type 3	GM B (Gray Mfg Co. of Hartford, CT for IBM)
Hammer Spring	type 2
Trigger Housing Pin	type
Safety	type 2 or 3
Magazine Catch	type 3	W (Winchester)