SB 742-1
individual rounds having visual evidence of damage or other
CARTRIDGE, 4.2 INCH MORTAR
conditions that may preclude loading and firing. Unless the
rounds requiring gaging are truly representative of the lot
being inspected, they should be disregarded in evaluating the
a. FSC: 1315.
lot.
b. Ammunition type: Cartridge, 4.2 inch Mortar. Includes
b. Table K-1 identifies test and measurement equipment.
the following models: M328 series (WP), M329 series (HE),
M335 series (illuminating), and the M630 (tactical CS). The K-4. Inspection category and sampling plan.
M2 series WP or PWP and the M3 series HE are obsolete and
not specifically addressed in this appendix. If these models are
a. Inspection category.
encountered they should be inspected and classified using the
(1) Category V: 6 years (includes jungle pack HE and
applicable portions of this supply bulletin as a guide.
WP.
c. The 4.2-inch cartridges are spin-stabilized rounds fired
(2) Category W: 5 years (includes inert items and
from a rifled bore muzzle loading weapon. For a complete
description of these rounds, see TM 43-0001-28 and the jungle pack illuminating cartridges.
drawings for the particular round.
(3) Category X: 4 years (includes CS in jungle pack
and HE and WP not in jungle pack).
(4) Category Y:
3 years (includes illuminating
WP cartridges manufactured prior to 1966 may contain
cartridges not in jungle pack and bulk ignition cartridges or
bursters loaded with tetrytol. Lots, which contain tetrytol
bursters, will be placed in condition code F for replacement of propellant).
bursters.
Screening for evidence of explosive growth or
(5) Category Z: 2 years (includes CS not in jungle
exudation prior to issue for use is not considered practical or pack and bulk primers)
timely.
b. The sampling plan for inspection is according to
a. All IRI samples will be gaged using a profile and K-5. Specific inspection points.
alignment gage and concentricity gage. Gaging is not normally
a. Item will be inspected and classified according to
required during PI, RI, or UBLI.
Gaging, during these
chapter 2 and table K-2.
inspections (other than IRI), should be limited to
Description
NSN
Application
Inspection
Gage, profile and alignment
9278618
M329A2
Gage, profile and alignment
7258457
All except M329A2
Gage, depth and concentricity
7304529
M329 series unfuzed
deep cavity
Classification
Application
Inspection
Inspection
Method
Description
1. Critical:
a. Excessive number of increments
All
Visual
b. Insufficient number of increments
M328 series M329 series
Visual
Visual
c.
M328A1 M329A1
Visual
Bag loading assembly missing or damaged to the extent
M329A2
Visual
that propellant can escape
Visual
d.
M329
Visual
Pressure plate incorrectly assembled (reversed)
M329A1
Visual
e. WP leakage or evidence of leakage
M328 series
Visual
f. Zone weight markings incorrect
M328 series
Visual
M329
Visual
M329A1
Visual
g. Fuze not set on safe (except for Fuze, MT, M565)
Visual
h. Fuze safety wire or pin missing, broken, insecure or
Visual
improperly engaged
i. Supplementary charge pad missing
M329 series (unfuzed)
Visual
j. Fuze well liner missing
M329 series
Visual
(unfuzed)
k. Explosive extends above the top of the fuze well
M329 series (unfuzed)
Visual
l. Fuze well liner not fully expanded and not making contact
M329A2 (unfuzed)
Visual
with fuze well threads for full 360 degrees
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