soundness_ are developed by this test will be rejected.

TENSILE TEST

(Art. 28, O. D., U.S.A.)

After forging, the projectiles shall be annealed at a temperature of at
least 1,200 deg. F.; and after being annealed, tangential test specimens
shall be taken from the base or base prolonged of 2 per cent of the
projectiles from each lot selected at random by the inspector.

The tensile strength of the projectiles in a lot shall not vary more
than 20,000 pounds from the highest to the lowest.

CHEMICAL TEST

(Art. 30, O. D., U.S.A.)

A careful and complete chemical analysis shall be made of the metal of
each heat from which the projectiles are manufactured under these
specifications.

TESTS FOR THE DETECTION OF INITIAL STRAINS BORDERING ON RUPTURE

(Art. 31, O. D., U.S.A.)

After final treatment and before acceptance for the ballistic test, all
A.P. shot must be cooled to a temperature of about 40 deg. F., and then
suddenly heated by being plunged into a bath of water at a temperature
of from 180 deg. F. to 212 deg. F., as the Chief of Ordnance may direct.
When thoroughly heated to this temperature each projectile must be plunged,
with its axis horizontal, halfway into a bath of water at a temperature
not greater than 40 deg. F., and after a brief period shall be turned 180
deg. for a like immersion of the opposite side, after which the projectile
shall be removed from the bath.

This test shall be made in the presence of the inspector, and an
interval of at least three days must elapse between the final treatment
and the submission of the projectiles to this test. This test is not
required for shell.

BALLISTIC TEST

(Art. 32, O. D., U.S.A.)

Each lot of projectiles shall be subjected to the following ballistic
test:

After a final treatment and on presentation of the entire lot for
the ballistic test, the inspector shall select three projectiles to
represent the lot, which shall be finished, inspected and delivered
in the same manner as required for the rest of the lot.

(a) Armor-piercing shot. Two capped shot, sandloaded to standard
weight, shall be fired against a hard-faced Krupp armor plate from 1
to 1-1/2 calibres thick, secured to a timber backing in a manner
satisfactory to the Chief of Ordnance, with about the corresponding
velocity given by the following table, with the requirement that the
shot shall perforate the plate unbroken and then be in condition for
effective bursting.

I