Marking on right hand side plate. .303 2.222″ / BNP 18.5 TONS PER O”. Modern proof mark for .303-inch ammunition. From Birmingham Proof House. Pressure rated at 18 tonnes per square inch.
An in-depth study of the Vickers MG in use around the world throughout the 20th Century.
Marking on right hand side plate. .303 2.222″ / BNP 18.5 TONS PER O”. Modern proof mark for .303-inch ammunition. From Birmingham Proof House. Pressure rated at 18 tonnes per square inch.