1、I MIL-C-71128 (4) D 777790b 2028077 7TB I INCH-POND MIL-C-71128 (AR) AMENDMENT 4 17 December 1996 SUPERSEDING AMENDMENT 3 14 June 1996 MILITARY SPECIFICATION CARTRIDGE, 81MM PRACTICE, SHORT RANGE M880 LOADING, ASSEMBLING AND PACKING This amendment forms a part of MIL-C-71128 (AR), dated 26 May 1992,
2、 and is approved for use by the U.S. Army Armament Research, Development and Engineering Center, and is available for use by all Departments and Agencies of the Department of Defense. PAGE 3 3.3.7 Add the following: “3.3.7 Dud pluqs. 3.3.7.1 Confisuration. Three dud plugs shall be present and proper
3、ly inserted into the projectile body. 3.3.7.2 Dud plus push in - push out force. No dud plug shall push into the required test plate using a force greater than 40.0 pounds and shall not be capable of being pushed out of the required test plate using a force of less than 25.0 pounds at a temperature
4、of 70F 2 -3F when tested as specified in 4.5.5.“ 3.4.1: Delete in its entirety and substitute: “3.4.1 Misfires. The cartridges shall not fail to fire from the weapon when they are initially dropped into it.“ AMSC N/A FSC 1315 DISTRIBUTION STATWENT A. Approved for public release; diatribution i8 unli
5、mitad. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-C-71128 (4) 9999906 2028100 24T = MIL-C-71128 (AR) AMENDMENT 4 PAGE 3 (cont) * Delete 3.4.2 in its entirety and substitute: “3.4.2 Short rounds. Cartridges having a horizontal range less than
6、 80 percent of the average horizontal range (calculated without the short rounds) will be classified as a short round. It PAGE 4 3.4.4: Delete in its entirety and substitute: “3.4.4 Ranse and deflection precision. The cartridge shall have a horizontal range probable error (PEr) less than 15 meters f
7、or all zones when calculated to the nearest one tenth (0.1) meter. The deflection probable error (PEd) shall be less than 15 meters for all zones when calculated to the nearest one tenth (0.1) meter) .I Add : 113. 4.9 Dud pluq function. 3.4.9.1 Functioned round. All dud plug heads (regardless of ste
8、ms) shall blow out of the projectile body upon fuze function. 3.4.9.2 Inert round. No dud plug head (regardless of stems) shall exit the projectile body during ballistic flight or upon impact .I1 PAGE 6 * 4.3.3 (b) , Add after first sentence: “Graze impact duds shall not be counted for score. These
9、shall be recorded for information only and shall be x-rayed to document that the fuze was armed. Side impact duds shall be recorded for information only and x-rayed to document that the fuze was armed. If more than four side impacts occur, the first article sample represented by he sample shall be r
10、eferred to the technical agency for disposition. In either of the above cases, if the x-ray reveals that the fuze did not arm, the fuze shall be considered to be a dud.“ * 4.3.3 (c), Delete in its entirety and substitute: c. One or more short rounds occur at +110 degrees F or +70 degrees F. Two or m
11、ore short rounds occur at O degrees F.“ 2 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-(2-71128 (AR) AMENDMENT 4 PAGE 6 (cont) 4.3.3: Delete g.“ and “h.“ in their entirety and substitute: “g. If the weapon is damaged by abnormal wear of the in
12、terior or of the firing pin, or caused by.excessive pressure. h. Two or more improper impact signatures occur. Add the following: II i. All three dud plug heads (regardless of stems) are missing from the projectile body in the inert fuze ballistic test. Two or more dud plug heads (regardless of stem
13、s) fail to exit projectile bodies (accumulatively, i.e., two remaining in a single projectile or one each remaining in two projectiles) in the live fuze ballistic tests (except in the case of a particular round that was an actual dud, in which case paragraph “i.“ above applies) .I1 PAGE 7 Table I, C
14、artridge, 81mm, Practice Short Range, under Conformance Criteria: Delete: 1172“, and substitute: “96“. Add the following: “Dud Plug . . . (dwg. 12961001) Examination for defects . 30 . 3.1 . 4.4.2.9 Push in push out test . 30 . 3.3.7.2 . 4 -5.5“ . PAGE 8 4.4.1: Delete the word “interfix“ from the te
15、xt from lines a., b., c., d. ande. Add the following: “f. Dud plugs from one inspection lot.“ 3 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-C-73328 (4) 9999906 2028302 052 MIL-C-71128 (AR) AMENDMENT 4 CLASSIFICATION CRI TI CAL 1 2 3 MAJOR 108
16、 109 110 111 112 3 EXAMINATION OR TEST Fuze striker in armed pos it ion Breech plug assembly firing pin not below flus1 after assembly to round Powder from energetic cartridges found on outside of round Obturator ring missing Fin, tail cracked, damagec or distorted Fuze packing clip missing or impro
17、perly assembled Zartridge assembly fails to fully enter complete round alignment gage Any dud pluqs missinq PAGE 10 4.4.2.1, Major 105: Delete: REQUIREMENT PARAGRAPH 3.3.4 3.3.3 3.1 3.3.2 3.1 3.1 “Length of large outside diameter section“, INSPECTION METHOD REFERENCE Gage Gage Visual Visual Visual V
18、isual Gage (b) and 3.3.1 3.3.7 substitute: Visual“ “Length between large outside diameter aft face to firing pin point“. acking clip missing from 100% PAGE 15 3.2 isual“ 4.4.2.5, Delete Specials A, B, C, D, E, F, G and H in their entirety. Add the following: CONFORMANCE CRITERIA 100% 100% 100% 100%
19、100% 100% 100% 100% NOTES : Delete : “ (a) If and substitute : “ (b) I. PAGE 18 4.4.2.6: Delete Special A in its entirety. Add Major 101 as follows: i 4 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-flIL-C-7LL28 (4) 9999906 2028103 T59 MIL-C-7 11 2
20、 8 (AR) AMENDMENT 4 PARAGRAPH TITLE “4.4.2.9 Dud Plug CLASSIFICATION EXAUINATION OR TEST CRITICALNone defined MAJOR 101 Push in - push out test 201 Poor workmanship MINOR PAGE 21 DRAWING NUEIBER 12961001 1NEXT HIGHER ASSEMBLY CONFORMANCE REQUIREMENT INSPECTION UETHOD SHEET 1 of CRITERIA PAFiAGRAPii
21、REFERENCE 30 3.3.7.2 Test/4.5.5 30 3.6 Vi sua 1 4.4.2.9 Add the following: 4.4.3.1.1: Delete iic.ll in its entirety and substitute: “c. Short rounds, -Major defect (see 3.4.2) .I Delete in its entirety and substitute: “e. Metal parts separation, Major defect (see 3.4.3) . Add : “i. All dud plug head
22、s out of any one projectile in the inert fuze ballistic test, Critical defect (see 3.4.9.2) .*l. j. Two or more dud plug heads remain in the live fuze ballistic test, Major defect (see 3.4.9.1) .l. * 4.4.3.1.2(b), Add after first sentence: “Graze impact duds shall not be counted for score. These sha
23、ll be recorded for information only and shall be x-rayed to document that the fuze was armed. Side impact duds shall be recorded for information only and x-rayed to document that the fuze was armed. If more than four side impacts occur, the first article sample represented by he sample shall be refe
24、rred to the technical agency for disposition. In either of the above cases, if the x-ray reveals that the fuze did not arm, the fuze shall be considered to be a dud.“ * 4.4.3.1.2(c), Delete in its entirety and substitute: ,IC. One or more short rounds occur at +110 degrees F or +70 degrees F. Two or
25、 more short rounds occur at O degrees F.“ 5 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-C-71128 (AR) AMENDMENT 4 PAGE 21 (cont) 4.4.3.1.2: Delete i. and “j.“ in their entirety and substitute: (1 i. All three dud plug heads (regardless of stem
26、s) are missing from the projectile body in the inert fuze ballistic test. j. Two or more dud plug heads (regardless of stems) fail to exit projectile bodies (accumulatively, i.e., two remaining in a single projectile or one each remaining in two projectiles) in the live fuze ballistic tests (except
27、in the case of a particular round that was an actual dud, in which case paragraph “i.“ above applies) .I 4.5.1.1, first paragraph, after second sentence: Add the following: “All rounds shall be fired onto a flat, nongrassy earthen surface that is not marshy or frozen.“ PAGE 22 4.5.1.1: Add the follo
28、wing: “d. One group of 24 each with inert fuzes conditioned for at least 24 hours at O degrees F 2 2.5 degrees F (see 4.4.3.1.2), shall be fired at charge 3.“ 4.5.1.1, last subparagraph: Delete and substitute: “The individual deflections and ranges (accuracy of both to 0.01 meter) and muzzle velocit
29、ies shall be calculated to the nearest 0.1 meter and recorded on the firing record for groups a, b, and c above.“ PAGE 23 Add the following: “4.5.5: Push in - push out test. Major defect. A hardened steel test plate of 1 x 2 x 1/4 inch is required for this test. There is to be a 0.250 2 .O01 diamete
30、r thru hole (having an internal surface finish of 32 maximum) in the steel plate. The sample of dud plugs to be tested shall be preconditioned at a temperature of 100 degrees F 2 5 degrees F for a period of not less than 24 hours nor more than 48 hours prior to being subjected to this test. The prec
31、onditioned dud plugs shall be tested not earlier than 15 minutes after removal from the Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-C-71128 (AR) AMENDMENT 4 PAGE 23 (cont) conditioning box nor later than one (1) hour after removal from the co
32、nditioning box. Press a sample dud plug into the hole using an arbor press until the head is 0.0625 2 0.02 inch above flush with the plate surface. At this point, the push in test is completed. Record the maximum force. Turn the steel plate over and push the dud plug out of the steel plate to 0.0625
33、 2 0.02 inch above flush using the same arbor press. Record the maximum force required to push out the dud plug. At this point, the push out test is completed. Compute sample mean (xbar) and standard deviation (sd). Insert these into the following formulas: Accept if: a. xbar(1n) = 37.0 pounds max.,
34、 xbar(1n) + 3 sd(1n) = 40.0 pounds max. and b. xbar(0ut) = 30.0 pounds min., xbar(0ut) - 3 sd(0ut) = 25.0 pounds min. and no individual x(0ut) less than 25.0 pounds. Any dud plug sample that does not meet the above requirements shall be cause for lot rejection. Each test sample quantity may be exami
35、ned for outliers using the Grubbs T statistical test (see 6.12). A maximum of two outliers may be removed from the sample quantity.“ PAGE 25 6.10 Delete in its entirety. 6.11 Add the following: “6.11 Insoection lot definition. A homogeneous collection of units of product or one shipment of component
36、 parts or assemblies from a subcontractor, bearing identification and treated as a unique entity from which a sample is to be drawn and inspected (and tested) to determine conformance with the acceptability criteria. I 7 Provided by IHSNot for ResaleNo reproduction or networking permitted without li
37、cense from IHS-,-,-MIL-C-73328 (4) m 9999906 2028306 768 m MIL-C-71128 (AR) AMENDMENT 4 PAGE 25 (cont) 6.12 Add the following: “6.12 Outlier test. When the accept criteria is not met and if it is suspected that a statistical outlier may be present in the sample of 30 observations. Arranqe the observ
38、ed values in Using the where : If x1, value the order of-increasing magnitude (Xi, X2 1. Xn-1, Xn. statistics calculated for the sample, calculate Tn - Tn = Xn - X S the smallest value, rather than Xn, is the doubtful test criterion is: arithmetic average of all n values estimate of the population s
39、tandard deviation based on the sample data calculated as follows: L JL If Tn is less than or equal to 2.745, the highest value may not be eliminated. The lot is rejected. If Tn is greater than or equal to 2.745, the largest value obtained in the sample shall be eliminated and the sample statistics X
40、 and s shall be recalculated using the twenty-nine remaining values. This shall be compared to the accept criteria. If the criteria is met, accept the lot. If not, the same procedure shall be followed for the Xn-1 observation. Calculate Tn-1 based on the new statistics of the remaining sample of 29.
41、 If Tn-1 is less than or equal to 2.730, the lot is rejected. If Tn-1 is greater than or equal to 2.730, then this observation shall be eliminated and the sample statistics calculated based on the remaining 28 observations. If these values meet the accept criteria, accept the lot. If the accept crit
42、eria is still not met, reject the lot .I1 6.13 Add the following: “6.13 Marshy around. Marshy ground is defined as an earthen surface that contains standing water or free flowing (fluid) mud or a combination of both.“ a Provided by IHSNot for ResaleNo reproduction or networking permitted without lic
43、ense from IHS-,-,-. MIL-C-71128 (AR) AMENDMENT 4 PAGE 25 (cont) 6.14 Add the following: “6.14 Frozen mound. Frozen ground is defined as earthen ground within which water has frozen creating a hard surface.“ * Add the following paragraphs: “6.15 Graze impact dud. A graze impact dud is a fuze dud caus
44、ed solely by the fuze hitting an object in the impact area (e.g. rocks) on its side and damaging the fuze prior to ground impact. This shall be determined by the proving ground test director based on his examination of the rounds point of impact. 6.16 Side impact dud. A side impact dud is a fuze dud
45、 caused solely by the cartridge impacting on its side (without the fuze hitting an object prior to ground impact where the fuze striker shows no evidence of impact. This shall be determined by the proving ground test director based on his examination of the rounds point of impact.“ The margins of th
46、is amendment are marked with an asterisk, or vertical line to indicate where changes (additions, modifications, corrections, deletions) from the previous amendment were made. This was done as a convenience only and the Government assumes no liability whatsoever for any inaccuracies in these notation
47、s. Bidders and contractors are cautioned to evaluate the requirements of this document based on the entire content irrespective of the marginal notations and relationship to the last previous amendment. Custodian: Army-AR Preparing activity: Army-AR (Project 1315-0 159) 9 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
