ndependent
of the charge.

272. The XI-inch gun, at 10 deg. elevation, gives for the mass of grape or
canister a range of about 1,300 yards; the spread about 10 deg.. They may
therefore be used with great effect against boats or exposed bodies of
men.

273. A stand of grape is not to be used with any other projectile.

274. Canister or case-shot, prepared for immediate use, are supplied
for all guns, including boat and field howitzers, and are effective at
short distances against boats or exposed bodies of men; they may be
used also, under favorable circumstances, against the tops of an
enemy.

275. Shrapnel-shell or spherical case-shot is intended to exceed the
range of canister, and is to be used only under the same
circumstances, but at an increased distance. Canister is more
effective at from 250 yards with the 12-pdr. howitzer, to 400 yards
with the XI-inch; but beyond those distances shrapnel should be used
up to 900 yards for the 12-pdr., and 1,500 with the XI-inch. A
well-delivered shrapnel-shell from a heavy gun must sweep away the
crew of a pivot or other gun, on a spar-deck not protected by
bulwarks. The 'distant firing' charge is always to be used with
shrapnel.

SEVENTH COMMAND.

"PRIME!"

"_He inserts a primer and turns the hammer down upon it._"

276. To prevent the primer from being blown out of the vent by the
blast of the next gun, as occasionally happens on light-covered decks.

With guns of the old pattern this cannot be done, because, if turned
down, it would interfere with the aim.

277. It is essential that the head of the primer shall be placed flat
and pressed close upon the vent, that the hammer may strike it fairly.
The tip of shellac, by which the lower end of the tube is sealed,
occasionally obstructs the jet of flame so as to split the tube. In
this case the flame is dispersed laterally, and fails to ignite the
charge; it is therefore a good precaution to pinch the end of the tube
before putting it into the vent.[40]

278. The tubes of all the primers are carefully gauged before issuing
them for service; but such as, from any cause, become so much enlarged
as not to go easily into the vent, should be rejected without
attempting to force them down.

It will occasionally happen, either from carelessness or inattention
to the instructions given for the proper manner of pulling the
lock-string, that the head of the primer will be crushed without
exploding it. Frequently a se