Why defence pricing splits so unevenly
A government price index only works if many producers sell a similar product in a real, repeated market. Commercial aircraft and ships are built and sold that way, even when a military buys them. Tanks, missiles, and small arms mostly are not — a handful of contractors sell almost entirely to one government buyer, at negotiated prices that never appear in a public survey.
That difference is the whole story for defence pricing. Two sub-sectors have real indices. Three do not.
Military aircraft — indexed
The United States publishes a monthly Aircraft Manufacturing Producer Price Index. Confirm the current series ID at bls.gov/ppi before citing it, since series get renumbered. This index covers all aircraft manufacturing together, civilian and military combined — it is not a military-only number, so do not label it as one in a contract.
Weight the composite toward aerospace-grade metals, jet engines, avionics, and skilled aerospace labour, in roughly that order of cost share.
Naval systems — indexed
Ship Building and Repairing also has a real, published monthly Producer Price Index in the United States. It covers ships. It does not cover boats — boat building is a separate, smaller index. Do not conflate the two if the contract is specifically for larger naval vessels.
Weight the composite toward shipbuilding steel, propulsion systems (engines and turbines), and shipyard labour.
Land systems, missiles, and small arms — not indexed
Armoured vehicles, guided missiles, and small arms (the weapons themselves, not ammunition) do not have published government price indices that a direct check could confirm. This is not a data gap to work around with a proxy — it reflects a real absence of a competitive market these products are sold into.
Build these three categories entirely from an input composite: armour steel or specialty alloys, engines or propulsion systems, electronics and guidance systems, and skilled manufacturing or engineering labour, weighted by their actual share of contract cost. Small arms ammunition is the one exception worth knowing — the ammunition itself (not the weapon) does have a real, published US price index, so a contract specifically for ammunition supply can use it.
The one mistake to avoid
Do not assume every defence product category has a government price index just because aircraft and ships do. Citing a specific index code in a contract for armoured vehicles or missiles when no such index exists creates a clause nobody can actually execute — check bls.gov/ppi directly before naming a series in the contract text.