PRIMER, PERCUSSION: MK2A4
Std OTCM 36841 dtd 1958.
This primer is used with a variety of separate-loading ammunition rounds to initiate burning of the propelling charge,
Percussion Primer MK2A4 is a brass cylinder with an extraction flange base, containing a charge of 19 grains of black powder, A primer cup in the center of the base contains a small quantity of sensitive primer composition, An anvil, gas check cone, and plug are installed between the primer cup and the black powder charge. The black powder is sealed in the primer case by a closing disk at the rear and a cork washer at the front end.
The primer is inserted in the firing lock of the weapon. When struck by the firing pin, the primer cup is indented, compressing the sensitive primer composition against the anvil. The primer composition detonates from the impact shock and flashes through a port in the plug to ignite the black powder charge in the primer case, The gas check cone prevents blowback in the event the primer cup is ruptured, The burning black powder charge initates burning of the propelling charge.
TM 43-0001-28 Tabulated Data:
Length 1.595 in.
Diameter 0.348 in.
Filler and weight Black powder,
Lower limit 40°F
Upper limit +125°F
Lower limit 80°F (for periods of not more than 3 days)
Upper limit +160°F(for periods of not more than 4 hr/day)
*Packing 250 primers in shipping container; 2 containers in wirebound box
*Packing Box: Weight 37 lb
*NOTE: See DOD Consolidated Ammunition Catalog for complete packing data including NSN's.
Shipping and Storage Data:
Quantity-distance class 3
Storage compatibility group — B
DOT shipping class C
DOT designation CANNON
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