Cylinder 1 of the brake and variable recoil control rod 2 are stationary during recoil and counterrecoil. Rod 3 and piston 4 recoil together with the barrel. At this, fluid from working end d of cylinder 1 is forced out into space e where it divides into two streams: one flowing into idle end b of the brake cylinder and the other pushing back moderator valve 6 and passing into space f. Upon counterrecoil, the fluid advances rod 3 onto control rod 2 and moderator valve 6 is pressed against the end face of the control rod, closing the hole of the valve. Fluid from space f escapes only through grooves a on the inside surface of rod 3 into space e. After filling the vacuum, fluid from end b is forced into end d.
$3771$SHP,FD$