OP 820 40MM Antiaircraft Gun
40MM Machine Gun Mechanism 1943

Mark 1, Mark 2, Mark 1 MOD 1, Mark 2 Mod 1
40MM Gun Barrel
Mark 1 40MM Sight Mark 3 Mark 4
Description and Operation


In the pages of OP-820 shown here, the following pages are blank: Page 4, 10, 16, 40 and 50

PRELIMINARY AI (This page)
Preliminary BI
Chapter I Introduction
Chapter IIA Mechanism
Chapter IIB Mechanism
Chapter III Barrel Assembly
Chapter IV Sights
Chapter V Cyclid Operatoin of the Gun Mechanism
Chapter VI Loading and Unloading
Chapter VII Casualties
Chapter VIII Functional Check-Off List
Chapter IX A Assembly and Disassembly
Chapter IX B Assembly and Disassembly
Chapter IX C Assembly and Disassembly
Chapter IX D Assembly and Disassembly
Chapter X A Parts List
Chapter X B Parts List
Chapter XI Appendix

cover page OP 820 changes OP 820 OP 820 changes OP 820 distribution OP 820 distribution clearance of jams clearance of jams clearance of jams OP 820 corrections Instructions for loading loaded and safe clearing live ammunition

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Preliminary B1