Cartridges : Projectiles : Gas Checks : Fuzes & Tubes

Gas Checks

 

A gas check is flat plate of metal used to impart spin to a projectile in a rifled gun and to seal the bore. It is placed behind the projectile on loading the gun and falls away when the projectile leaves the muzzle. The idea emanated from the Elswick firm and was a means for overcoming erosion caused by windage. The first gas checks were a cup of papier-mâché. These were replaced in 1878 by ones constructed of copper with 3% zinc so they would not break up in flight. A later adaptation was to fix the gas check to the projectile. Because the gas check made the shell rotate, studs were no longer required.This was the precursor of the copper driving band on modern B.L. shells. The earlier gas checks were smooth and the action of firing expanded them into the grooves of the rifling. When slow burning powders were introduced this occurred more gradually and gas checks with ribs to fit the grooves were produced.

 

8inch RML Howitzer Gas Check

 

 

 

gas check
gas check

8-inch RML Howitzer (front)
Found South of Fort Bovisand, Plymouth

8-inch  RML Howitzer (back)
Photos : Paul Frear

The gas check for the 8-inch Howitzer was suitable for common and shrapnel shells, the curved portion of the base of the shell being cast with radial grooves into which the inner surface of the gas check is compressed by the pressure on firing; the gas check is also at the same time firmly attached to the base of the shell by being compressed into the groove or neck round the locking rim at the rear end of the shell. It is made with projections round the circumference corresponding with the rifling grooves of the howitzer.

6.6-inch gas check

9inch R.M.L. gas check 16inch R.M.L. gas check

6.6-inch RML Howitzer

9inch R.M.L.

16inch R.M.L.

 

Description of the above gas checks kindly supplied by Mike McLean.

Detailed information on Gas Checks can be seen in the Wikipedia article here:

Gas-checks in British RML heavy guns