Heligun EX17.pdf - Forgotten Weapons

CYCLING AND CAM SHAPE
HTC-AD 66-29
An improved earn shape on the revolver is needed to increase the gun
cycle reliability in rotation and return to battery. An increase in breech
travel by 1 I 8 inch will allow the use of a cylindrical cam with a substan­
tially reduced pressure angle. The improved cam shape will permit a
reduction in the recoil spring load and the amount of gun gas boost. The
resulting reduction in gun cycle loads will give better operation on
resilient mounts. High loads between the cam surfaces (Figure A-3) and
the cam followers have caused wear of the metal (Figure A-4). The pro­
posed cam shape will have the same proportions as the proven cam in the
Mk 11 gun. Gun cycling difficulties now account for 16 percent of the
stoppages.
PNEUMA TIC TUBE
The pneumatic tube transports gun gas from the first-fire barrel to the
last-fire, gas- actuated firing pin. Changes in the amount of powder
residue or fouling have been recently noted, following three- to four­
thousand-round firi