1、MILITARY SPECIFICATION GUNS, AIRCRAFT, 20h MARK 12 MOD O AND MOD 3 1. SCOPE 1.1 Scope. - This specification covers the procurement re- quirementsor 20MM Aircraft Guns Mark 12 Mod O and Mod 3, including 20MM Gun Barrels Mark 11 and Mods and their spare and replacement parts. 2. APPLICABLE DOCUMENTS 2
2、1 The following specifications, standards, drawings, and publications, together with those listed on applicable draw- ings, of the issue in effect on the date of invitation for bids, form a part of this specification: SPECIFICATIONS MILITARY MIL-I-O - Inspection Requirements, Non-destructive, MIL-P
3、19419 - Plating, Chromium, Electro-deposited for Aircraft Materials and Parts. (on Bores and Chambers of 20MN Mark 11 Gun Barmls). . STANDARDS MILITARY MIL-STD-10 - Surface Roughness, Waviness, and Lay. MIL-STD-105 - Sampling Procedures and Tables for M.XL-STD-129 - Marking for Shipments and Storag
4、e. MIL-STD-130 - Identification Markings of U. S. Mili- Inspection by Attributes. tary Property. BUREAU OF ORDNANCE NAVORD OSTD 2 - Method of marking Ordnance Material. / . THIS DOCUMENT CONTAINS a$ PAGES. , . . 1-1 r; ,- .- - FSC i005 h _- - Provided by IHSNot for ResaleNo reproduction or networkin
5、g permitted without license from IHS-,-,-DRAWINGS BUREAU OF ORDNANCE 982519 - 20MM Ammunition for Aircraft Gun Mk 12, Tar- 982520 - 20MM Dummy Round Mk 103, for Aircraft Gun Mk 12. 1265884 - Plate. i265937 - Linear Potentiometer for Mk 12 Proof Mount 1445196 - 20MM Dummy Round Mk 104, for Aircraft G
6、un Mk 12. i467992 - Standard Proofing Equipment for 20MM Machine Gun Mk 12 and Mods and 20MM Feed Mech. Mk 7 Mods 1.467995 - Standard Proofing Equipment for 20MM Machine Gun Mk 12 Mod 3, and Feed Mechanism Mk 9 Mods 4 and 5; General Arran ement. 1483623 - Cam, Charger Latch (Modified 7 , i500629 - P
7、ower Supply Console (for testing 2MM Ma- chine Gun Mk 12 Mods). 1515855 - General Arrangement Wiring Diagram, Power Supply Console (for testing 20MM Machine Gun Mk 12 and Mods). 1591132 - Wiring Diagram, Standard Proofing Equip. LD 172560 - Synchronizing Switch Mk 1 Mod 1. LD 255941 - 20MM Ammunitio
8、n Link Mk 2 Mod O. LD 256043 - 20MM Ammunition Link Mk 2 Mod 1. LD 256072 - Shipping Container for one 20MM Aircraft Gun Mech. Mk 12 Mods O and 3. LD 256073 - Shipping Container for 20MM Gun Barrels Mk 11 Mod 2. LD 261649 - Proof Mount Assembly, 20MM Barrel. LD 266032 - 20MM Aircraft Gun Mk 12 Mod O
9、 LD 266061 - 20MM Feed Mech. Mk 7 Mod 2. LD 276462 - 20MM Feed Mech. Mk 7 Mod O. LD 288830 - 20MM Ammunition Link Mk 2 Mod 2. LD 413798 - 20MM Aircraft Gun Mark 12 Mod 3. LD 413813 - .Power Supply Console (for testing 20MM Ma- chine Gun Mk 12 and Mods) List of Drawings, Assembled Units and Connecti
10、ng Parts. LD 413815 - Standard Proofing Equip. (for 20MM Gun Mk 12 and 20MM Feed Mech. Mk 7 and Mk 8). LD 413816 - Fixed Rigidity Adapter Assembly LD 413850 - Standard Proofing Equipment for 20MM Machine Gun Mk12 Mod 3 and Feed Mechanism Mk 9 Mods 4 and 5, get Practice Round. (G.A.) Provided by IHSN
11、ot for ResaleNo reproduction or networking permitted without license from IHS-,-,-LD 414203 - Electrical Equipment (for Power Supply Console for Testing 20MM Aircraft Gun Mk 12 Mods). LD 482078 - 20MM Feed Mech. Mk 9 Mod 4. LD 482079 - 20MM Feed Mech. Mk 9 Mod 5. SK 234828 - Gun Mount Assembly 20“ D
12、epression). SK 234831 - Gun Mount Assembly Horizontal), SK 401113 - Link Chute SK 401119 - Link Chute Fabrication. Fabrication. PUBLICATIONS BUREAU OF ORDNANCE OP 400 - General Instructions for the Design, Manu- OP 1866 - 20MM Aircraft Gun Mk 12 Mods O and 2, OP 1912 - 20MM Feed Mechanism Mk 7 Mod O
13、 Instruction OP 1922 - 20MM Aircraft Gun Mk 12 Mods O and 2, Over- OP 2096 - Aircraft Guns, Test and Evaluation Pro- OP 2185 - 20MM Feed Me.chanism Mk 9 Mods 4 and 5 (Copies of specifications, standards, drawings, and publi- facture and Inspection of Naval Ordnance Equipment. Description, Operation
14、and Maintenance. Manual. haul Manual. cedure Manual. Instruction Manual. cations required by contractors in connection with specific procurement functions should be obtained from the rocuring activity or as directed by the contracting officer . 2.2 Other publications. - The following documents form
15、a part of this specification. Unless otherwise indicated the issue in effect on date of invitation for bids shall apply. P NATIONAL BUREAU OF STANDARDS Handbook 28 - Screw Thread Standards for Federal Services (with Supplements), (Application for copies should be addressed to the Superin- tendent of
16、 Documents, Government Printing Office, Washington 25, D, C.). 3 1- . %_ -4. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-G-21615 (Nord) 3. REQUIREMENTS -. 3.1 General. - General requirements shall be in accordance with Publication OP 400. The
17、 design characteristics, mechani- cal requirements, and the performance of the gun mechanisms and gun barrels covered by this specification shall conform to the applicable drawings and thls specification. will be determined by the contractor; however, the obligation is on the contractor to.satisfy t
18、he procuring activity as to full compliance with the contract, the applicable drawings, and this specification. The contractor shall provide adequate safety devices to prevent injury to personnel during the tests 3.3 Material. - Material shall conform to the requirements and specifications specified
19、 on the applicable drawings, In procuring materials the contractor shall provide for material lot formation as specified in 4.2.1 and 4.2.2. . 3.4 Physic81 requirements. - The physical requirements of the componentparts of the gun mechanisms and gun barrels cov- ered by this specification shall be i
20、n strict accordance with the applicable drawings and this specification, In addition, the component parts of these gun mechanisms and gun barrels, shall be free from cracks, porosity, voids, scale, or other defects which may make the part unsuitable for the intended purpose. 3.2 Contractor obligatio
21、n, - Mean$ and methods of manufacture of 4.4, 3.5 Finishes, coatings, and tolerances. - 3.5.1 Surface roughness, waviness, and lay. - Corners, edges, and surfaces shall be finished in strict accordance with draw- ing requirements and shall be free from any roughness, tool marks, machining mismatches
22、 or any other discrepancies which would tend to initiate cracks r cause galling or other mal- function. Surface roughness symbols shown on the drawing shall be interpreted in accordance with Standard MIL-STD-10. 3.5.2 Protective coating, - Unless otherwise Specified in the contract or order, gun ba
23、rrels shall be plated in accordance with Specification MIL-P-19419. All other parts of the guns shall be plated, coated, or treated as specified on the appli- cable drawings. 3.5.3 Dimensions and tolerances. - Dimensions and tolerances shall be in strict accordance with the applicable drawings and t
24、his specification, Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-3.6 Gun barrel machining. - Extreme care is essential in ma- chining-the gun barrel, During rough turning and rough boring operations, the- tool shall be reset a sufficient number of
25、times to assure that all stresses, which may cause distortion of the gun barrel, are removed prior to finish machining. drawings, all threads shall conform to the National Bureau of Standards Handbook 28, and the not-go practice shall be as set forth in the supplement to the aforementioned handbook.
26、 The class of fit shall be as specified on the applicable draw- ings. 3.7 Threads. - Unless otherwise specified on the applicable 3.8 Gages,. - The contractor shall provide himself with whatever gages are necessary to insure that the parts and as- semblies covered by this specification will meet the
27、 dimen- sions and tolerances specified by the applicable drawings, and this specification. If so desired, and upon request of the contractor, the Government will furnish available drawings of the applicable Government final inspection gages required by the contractor. This procedure shall not serve
28、to relieve the contractor of his responsibility in the design and manu- facture of such other gages as may be required to satisfactorily fulfill the contract requirements. 3.9 Spare parts. - When procurement documents (see 6.2) stipulate that spare parts are to be furnished with assembled guns, the
29、spare parts shall be produced concurrently with, under essentially the same manufacturing conditions, and of $he same material lots as like parts used in the assembled guns . 3.10 Interchangeability. - All parts having the same part number shall be completely interchangeable with each other and with
30、 like parts of other manufacture in respect to instal- lation and-performance. Parts Joined together by welding, brazing, OP riveting shall be interchangeable as assemblies. 3.11 Identification marking. - Each component of the guns shall be marked in accordance with the applicable drawings and Stand
31、ards NAVORD OSTD 2 and MIL-STD-130, except that mark- ing with ink on metal parts will not be permitted. 3.12 Mechanical requirements (assembled gun). - 3.12.1 Breechblock lock. - The breechblock lock, when in the locked position, shall bear uniformly (minimum 75 percent bearing) in its seat in the
32、bolt and against the locking face of the breechblock Lo_ckbg key. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-3.12.2 Breechblock slides. - Camming surfaces on the breech- block slides shall contact simultaneously the right side and the left side
33、of the breechblock lock so as to exert equal pressure on both sides of the breechblock lock in locking the bolt. 3.12.3 Lock clearance. - The lock clearance of each gun shall be not more than 0.010-inch, nor less than 0.002-inch prior to proof firing. Lock clearance shall not increase more than 0.00
34、2-inch during proof and function firing. Lock clear- ance shall be measured as prescribed in 4.3.5. 3.12.4 Push rod interference. - Push rod interference meas- urements taken before and after proof and functional firing tests shall not-exceed the values listed in 4.3.6. The method of measurement sha
35、ll be as prescribed in 4.3.6. 3.12.5 Gun barrel bore diameter. - After proof and functional firing tests, the bore diameter measured across the lands shall not exceed, at any point, a dimension of 0.003-inch greater than the measured diameter prior to firing, The bore diameter shall be measured with
36、 a three-point star gage at 1-inch in- tervals throughout the entire length of the barrel. 3.13 Assembly. - Prior to bench tests and firing tests, the guns shall be assembled and serviced in accordance with the ap- plicable drawings and instruction manuals (Publications OP 1866 and OP 1922). kind du
37、ring assembly- or operation. There shall be no fitting or alteration of any 3.14 Government furnished material. - Government furnished material will be furnished when specified in the contract or order (see 6.2). nished material the contractor shall ascertain whether or not such material is defectiv
38、e or damaged. If such material is found to be defective or damaged, the contractor shall im- mediately notify the Government and the Government will repair or replace such material at no expense to the contractor. How- ever, if the Government furnished material is Found to be-in good condition and i
39、s accepted by the contractor and is subse- quently damaged or found to be defective, the responsibility for repairs or replacement and assembly cost incurred to the point of rejection shall rest with the contractor. Immediately upon delivery of Government fur- 3.15 Government loaned property. - Gove
40、rnment loaned prop- Damage to Government loaned property shall be the erty will Be furnished when specified in the contract or order (see 6.2). responsibility of the contractor. The contractor shall not machine, file, grind, scrape, or otherwise modify such property unless modification is specifical
41、ly authorized by the procuring activity . 7 ,/- 6 . - Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-3.16 Defects. - Guns shall perform satisfactorily when sub- mitted to the tests of 4.4. Evidence of any condition which indicates a tendency to gall
42、 bind, or otherwise adversely af- fect the rapidity and smoothness of function or the proper phase relationship of operation (see appendix), or which may cause undue wear, or indicates the presence of burrs, leakage of air, electrical defects, or any other defect that may ad- versely affect the per
43、formance or life of the gun shall be cause for rejection. 3.16.1 Rate of fire. - The rate of fire shall be not less than 925 nor more than 1075 rounds per minute, except that a maximum rate of 1125 rounds per minute will be allowed during the life test, 3.17 Supplementary requirements. - 3.17.1 Repo
44、rt of tests. - Accurate records of parts fail- ures, functional failure, parts replacement of each gun, and the applicable number of rounds fired, together with an analy- sis of any malfunction shall be recorded and forwarded to the procuring activity. . 3.18 Workmanship. - The quality of workmanshi
45、p shall be sueh as to assure compliance with all the reauirements of the ap- plicable drawings, standards, and specifications. 4. QUALITY ASSURANCE PROVISIONS AND TFST REQUIREMENTS 4.1 Sampling. - Unless otherwise specified, and when appli- cable, thk sampling plans and procedures used by the Govern
46、ment Inspector in the determination of the acceptability of products submitted by a supplier for Government inspection will be in accordance with the provisions of Standard MIL-STD-105. 4.2 Lots. - Materials, assembled guns, and parts shall be submittmor inspection and test in lots as specified in 4
47、2.1, 4.2.2, 4.2.3, and 4.2.4. 4.2.1 Material lot. - A material lot shall consist of all raw material of the-same kind or origin, melt or heat, procured and processed into prociuction at the same time, for manufacture of guns or spare parts. Each such lot shall.be submitted for inspection as prescri
48、bed in the applicable material specifi- cation. It shall be arranged in such a manner as to satisfy the inspector that all material in the lot is reasonably uni- form in quality and characteristics. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-4.2
49、2 Assembled gun lot, - An assembled gun lot shall con- The unif; sist of assembled guns and their spare parts which have been manufactured under essentially the same conditions. of product is an assembled gun and a set of spare parts, the latter having been manufactured concurrently and of the same materials as the like parts of the assembled gun.(see 3.9). An assembled gun lot consists of all such units of product pre
