The wings rotate limitedly on axles near their front edges, and thus on upstroke and downstroke they propel water backwards.

These incidents were sometimes caused by dropping the weapon on a hard surface with an impact sufficient to knock open the ejection port cover and propel the bolt backwards (but not enough to catch the sear).

However, others have countered that boats wouldn't move forward unless they propelled water backwards.

In particular, there is a major risk of a semi-auto gun being uncontrollably propelled backwards by the recoil and firing rounds at the shooter's back as well as any bystanders.

To propel the shell backwards.

The force of the shot propelled Marie-Cecile backwards and she lost her balance.

The Surplus Special fires its gun backwards to propel itself forwards for extra speed.

When this feature is activated, the propellers begin producing thrust in the opposite direction, propelling the aircraft backwards to slow it down.

It was filled with 25 lb of Torpex and the weapon was rocket propelled backwards to the line of flight at a speed that counteracted the aircraft's forward motion.

The guns were sufficiently powerful, and the punts themselves sufficiently small, that firing the gun often propelled the punt backwards several inches or more.