| 摘要 |
<p>A shot-gun (1) with gas take-off has a fore end stock (20) which is movable longitudinally of the barrel (2) and lockable selectively in each of two positions: in one position, gases from the discharge of a cartridge in the gun, bleed from the barrel into the chamber (16) of a piston/cylinder unit (8, 5) to drive the piston (8) to operate an arming rod (4) of the shot gun automatically. In the other position, a valve member (30) prevents the discharge gases from entering the cylinder chamber, these gases being vented to the external environment: the stock is rigidly locked to the piston for manual operation of the arming rod by "pump" action on the stock in this latter position.</p> |
