(2) Replacement Factor (Column 3b). This column reflects the replacement factor assigned to
each nationally stock numbered maintenance repair part. This factor is assigned to the repair part on its first
appearance in the publication. The replacement factor, expressed as a decimal, indicates the average rate at
which the type of item so coded has been used by Marine Corps field units or the rate which design engineers
anticipate the item will fail, wear out, or othetrwise require replacement. All computations are based on a
replacement period of one year. Therefore, a replacement factor of 0.08, applied to an item in this stock list,
indicates that eight out of every one hundred of such items used in the end item of equipment to which this
publication pertains, is predicted to need replacement in one year. Likewise, 0.004 reflects that four out of
every thousand in use are predicted to require replacement in one year, whlie 2.0 shows that every one in use
is predicted to be replaced twice during each year.
(a) Initial authorized stockage levels of consumable and salvageable items for an organization
are to be computed for predicted consumption based on the number of items employed and/or supported by an
organization within the number of days for which stockage is authorized. In computing Garrison Operating
Stock or Mount-Out, authorized levels can be determined by the requiring Marine Corps unit by multiplying the
replacement factor times the quantity used per equipment, times the number of end items employed by the
using organization or supported by the service organization, times the authorized day level expressed in
months and divided by 12. Specific formulas and examples are provided in Marine Corps Order, MCO
The replacement factors used in initial stockage computations should be revised, if warranted, after
significant usage is experienced in accordance with the guidelines of MCO 4400.32A. The following formula
replacement factor, X represents actual usage experience (1 year), A represents the application per
equipment, and B represents the number of equipments supported.
W = A y B
(b) Initial allowances for maintenance float items (recoverability codes Rand D) for the FMF
and appropriate post and stations are as furnished by initial issue Actions.
Changes to maintenance replacement rates resulting from actual usage may require recomputation of
maintenance float allowances by holding units. Any required recomputation of maintenance float allowance will
be made in accordance with MCO 4000.6.
(c) The replacement factor for same as (S/A) items is indicated upon the first appearance of
the item in the major combination, component or assembly.
d. (ALL) National Stock Number (Column 4) indicates the National Stock Number assigned to the item
and will be used for requisitioning purposes.
e. (ALL) Descripion, (Column 5). Indicates the Federal item name and any additional description of
the item required. The abbreviation "w/e" when used as part of the nomenclature, indicates that the National
Stock Number includes all armament, equipment, accessories and repair parts issued with the item. A part
number or other reference number is followed by the applicable five digit Federal Supply Code for
Manufacturer. If two reference numbers and Federal supply Codes for manufacturer are listed, the first listing
refers to the Department of the Defense Drawing Number, the second listing refers to the actual part
manufacturer. Items that are included in kits and sets are listed below the name of the kit or set with the
quantity of each item in the kit or set indicated in the quantity incorporated in unit column.