1、 - r- 2 MI L-P-I8942A(OS) Amendment 3 25 August 1971 Supersed i ny Amendment 2 23 March 1966 MILITARY SPECIFICATION PROPELLANT FOR 20 MM AIRCRAFT GUN MARK 12 This amendment forms a part of Military Specification MlL-P-l8942A(NOrd) dated 18 December 1956 and has been approved for use by the Naval Ord
2、nance Systems Command, Department of Navy. By this amendment, basic specification MIL-P-l8942A(NOrd) is changed to read Mlt-P-I8942A(OS), and throughout the specification “Bureau of Ordnance shall be changed to “Naval Ordnance Systems Command“ and “BuOrd shall be changed to “NAVORDSYSCOM“ . I. Pace
3、I, Paragraph 2.1, Specifications, Military, Delete “MIL-P-11960 Propellants, General Specifications for Methods of Inspection, Sampling, and Testing“. Substitute “MIL-STD-256 Propellants; Sampling, Inspection and Testing“, 2, Page 2, paragraph 2.2, delete in its entirety and substitute: “2.2 Other p
4、ublications. The following documents form a part of this specification to the extent specified herein. Unless otherwise indicated the issue in effect on date of invitation for bids shall apply. Code of Federa 1 Reau i at ions 49 CFR 171-178 Hazardous Materials Reguations, Department of Transportatio
5、n XANUALS Department of Defense 4 I 45.26M DOD Contractors Safety Manual for Ammunition Explosives and Related Dangerous Material (Applications for copies of the above publications should be addressed to Superintendent of Documents, Government Printing Office, Washington, D.C. 20402)“. 3. Page 5, Pa
6、ragraph 3.12.1, Delete in its entirety and substitute 3.12.1: “Action Time. (See 6.3.2). When assembled in the 20 mm target practice round, the propellant shall ignite properly with the standard M52A3BI primer, The propellant action time shall be determined by firing 50 rounds in a Mann barrel. Acti
7、on time, defined as the interval between clos ng the fi ring key and the emergence of the project1 Js fj.q. the . 1 :. : 5 .$q. - - ti t. DQJr;Em= Ir- PkGE&/ Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- -_. MIL-P-189YZA (3) 13 W 9999706 0300038 7
8、 = 4.- - - *- MIL-P-I8942A(OS) Amendment 3 muzzle, shall be equal to or less than the values specified below: Mean Action time .O030 sec max. Standard deviation of Action time . .O005 sec max. Individual Action time ,0033 sec max.! 4. Page 7, ad3 new paragraph 3.16 as follows: “3.16 Safety Precautio
9、ns. The supplier shall observe the safety precautions of DOD 4 145,26M, as app I i cab I e. II 5, Page 7, paragraph 4.2, line i2 and 13, Delete “Powder Factory“ and substi tute “Ordnance Station“. 6, Page 8, Paragraph 4.4. I, I ine 2. Delete “MIL-P-I 1960“ and substitute “MIL-STD-286“. 7. Page 8, Pa
10、ragraph 4.4.1, line 5. Delete “102. I of MIL-P-I 1960B“ and substitute “lol. I .2 of MIL-STD-286“. 8. Fags 8, Paragraph 4.4.1, line 6. Delete “t03.3 and substitute 103.3.3“. 9. Page 9, Paragraph 4.4.3.2. Delete in its entirety and substitute 4.4.3.2 Action Timv. IO. Page 4, Paracraph 4.4.3.2.1. Dele
11、te in its entirety and substitute 4.4.3.2.1 Fifty 20 mrn target practice rounds shall be assembled as described in 4.4.3.4.1. Inese rounds shall be fired in a 20 mm aircraft accuracy barrel (Mann Garrel) and action times recorded. The action time for any individual round shall not exceed .O033 secon
12、ds. -. II. Page 9, Paragraph 4.4.3.4.1.1 Components and Assembly Delete lines 12 and 13, Primers: in its entirety and substitute. Primers: M52A331Primers shall be from a previously accepted primer lot containing approximately 50,000 primers. 19. Page 13, Faragraph 6.3.2, line 4. Delete 3.12.1. Prepar i ng Act i v i ty : (Proj. No.1375-N407) NAVY - OS t U Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
