There must have been quite a bit of work in that direction. This from July 6, 1861:

EXPERIMENTS WITH ‘McCARTY’S CENTRIFUGAL
GUN.

An intense crowd of persons assembled at the foot of
Thirty-second street, North River, this city, on the
afternoon of the 19th inst., to witness experiments
with Mr. R. McCarty’s centrifugal gun. A few per-
sons were permitted to examine it in the building be-
fore it was taken out for operation, but the interior
was not exposed. Its external appearance is almost
like that of a narrow fan-blower mounted upon a
long low carriage. The bullet case is placed in front,
and consists of a vertical circular box secured on a
shaft. In size it is three feet in diameter and about
three inches broad. A tube or bullet barrel 24 inches
long is placed tangentially at the top of the case and
serves as a guide for the discharge of the bullets. At
the center, on one side, is placed a small copper hop-
ner into which the bullets are fed from the tubes,
containing twelve iron balls, each 13~ inches in diam-
eter, and weighing four ounces. On the other side of
the axle of the case is a small pulley over which a
belt passes from a fly-wheel pulley near the back enil
of the carriage. The belt pulley receives a very high
velocity from the driver shaft, the speed being com-
municated through cog gearing. The driver shaft is
operated by. a large cr&nk lever at each side, and two
reciprocating brakes capable of permitting ten men
to work the machine. The power is accumulated by
rotating the centrifugal bullet case for some mo-
ments before the balls are discharged.

A large’ target of common inch plank was placed
in front of the gun at a distance of about 130 paces,
and after getting ‘up a high velocity on the machine,
by the men working at the brakes, a stream of about
sixty bullets was discharged in a few seconds. A
number of the bullets struck’the ground ricochetting
in front of the target; several passed over the tar-
get, and a number smashed through it and went
about 40 or 60 yards beyond. This was done three
times’ in succession. The tiThe of the centrifugal case
was elevated to about 40~, and several bullets were
discharged more slowly and with greater range than
before, but as they went into the river, we were un-
able to judge of the distance.

A number of army and navy officers were present,
and the experiments were conducted with more
promptness and dispatch than is usual in such cases,
Inventors and owners of new inventions, who make
public exhibitions, very frequently do injury to them-
selves, and impose upon those whom they invite as
witnesses, by not having all things arranged to com-
mence operations at the hour appointed. A fewweeks
since we went to see a series of experiments in gun-
nery, and were kept waiting three full hours after
the time appointed before the trial commenced.

Mr. McCarty was the first inventor who patented a
centrifugal gun in America (and in Europe also, we
believe). This was in 1838. There can be no ques-
tion about its ability to discharge a stream of bullets
without powder, by manual labor alone. Placed in
a situation to defend a narrow pass, or a breech in a
fort, against a storming party, it could throw a steady
stream of bullets against the foe. If is capable of
being operated by steam as well as manual power.’ A
very large gun, upon this principle, is now in the
course of construction by the inventor, which we ex-
amined in the workshop; it is intended to be driven
by a steam engine.

Would have to be big as a tank.