t. His cast-iron guns (fig. 13), many of
which are seen today in the battlefield parks, are easily recognized
by the heavy wrought-iron jacket reinforcing the breech. The jacket
was made by coiling a bar over the mandrel in a spiral, then hammering
the coils into a welded cylinder. The cylinder was bored and shrunk on
the gun. Parrotts were founded in 10-, 20-, 30-, 60-, 100-, 200-, and
300-pounder calibers, one foundry making 1,700 of them during the
Civil War.

All nations, of course, had large stocks of smoothbores on hand, and
various methods were devised to make rifles out of them. The U. S.
Ordnance Board, for instance, believed the conversion simply involved
cutting grooves in the bore, right at the forts or arsenals where the
guns were. In 1860, half of the United States artillery was scheduled
for conversion. As a result, a number of old smoothbores were rebored
to fire rifle projectiles of the various patents which preceded the
modern copper rotating band (fig. 12c, d, f). Under the James patent
(fig. 12c) the weight of metal thrown by a cannon was virtually
doubled; converted 24-, 32- and 42-pounders fired elongated shot
classed respectively as 48-, 64-, and 84-pound projectiles. After the
siege of Fort Pulaski, Federal Gen. Q. A. Gillmore praised the
84-pounder and declared "no better piece for breaching can be
desired," but experience soon proved the heavier projectiles caused
increased pressures which converted guns could not withstand for long.

The early United States rifles had a muzzle velocity about the same as
the smoothbore, but whereas the round shot of the smoothbore lost
speed so rapidly that at 2,000 yards its striking velocity was only
about a third of the muzzle velocity, the more streamlined rifle
projectile lost speed very slowly. But the rifle had to be served more
carefully than the smoothbore. Rifling grooves were cleaned with a
moist sponge, and sometimes oiled with another sponge. Lead-coated
projectiles like the James, which tended to foul the grooves of the
piece, made it necessary to scrape the rifle grooves after every half
dozen shots, although guns using brass-banded projectiles did not
require the extra operation. With all muzzle-loading rifles, the
projectile had to be pushed close home to the powder charge;
otherwise, the blast would not fully expand its rotating band, the
projectile would not take the grooves, and would "tumble" after
leaving the gun, to the utter loss of ra