An obturating ring is a ring of relatively soft material designed to obturate under pressure to form a seal. Obturating rings are often found in

artillery Artillery consists of ranged weapons that launch Ammunition, munitions far beyond the range and power of infantry firearms. Early artillery development focused on the ability to breach defensive walls and fortifications during sieges, and l ...

and other

ballistics Ballistics is the field of mechanics concerned with the launching, flight behaviour and impact effects of projectiles, especially weapon munitions such as bullets, unguided bombs, rockets and the like; the science or art of designing and acceler ...

applications, and similar devices are also used in other applications such as

plumbing Plumbing is any system that conveys fluids for a wide range of applications. Plumbing uses piping, pipes, valves, piping and plumbing fitting, plumbing fixtures, Storage tank, tanks, and other apparatuses to convey fluids. HVAC, Heating and co ...

, like the ''olive'' in a

compression fitting A compression fitting is a fitting used in plumbing and electrical conduit systems to join two tubes or thin-walled pipes together. In instances where two pipes made of dissimilar materials are to be joined (most commonly PVC and copper), th ...

. The term "

O-ring An O-ring, also known as a packing or a toric joint, is a mechanical gasket in the shape of a torus; it is a loop of elastomer with a round cross section (geometry), cross-section, designed to be seated in a groove and compressed during assembl ...

" is sometimes used to describe this kind of pressure seal.

Ballistics uses

Obturating rings are common in artillery, where the steel or cast-iron casing of the shell is too hard to practically deform to provide a tight seal for the propellant gases. An obturating ring which is called

driving band Russian 122 mm shrapnel shell, which has been fired, showing rifling marks on the copper driving band around its base and the steel bourrelet nearer the front A driving band or rotating band is a band of soft metal near the base of an artillery ...

made of a softer material is the standard solution for that problem. Mortar bombs also use obturating rings to provide a seal around the projectile.

Recoilless rifle A Recoilless rifle (rifled), recoilless launcher (smoothbore), or simply recoilless gun, sometimes abbreviated to "rr" or "RCL" (for ReCoilLess) is a type of lightweight artillery system or man-portable launcher that is designed to eject some fo ...

s and some artillery use rings with a reverse impression of the

rifling Rifling is the term for helical grooves machined into the internal surface of a firearms's barrel for imparting a spin to a projectile to improve its aerodynamic stability and accuracy. It is also the term (as a verb) for creating such groov ...

cut in them for a tighter seal even at very low pressures.{{clarify, date=May 2023 Another obturating ring may be used on sliding/falling breech-blocks from the opposite side of the chamber to provide a tight seal there if the charge is bagged and lacks a case (examples include early

Krupp gun Friedrich Krupp AG Hoesch-Krupp (formerly Fried. Krupp AG and Friedrich Krupp GmbH), trading as Krupp, was the largest company in Europe at the beginning of the 20th century as well as Germany's premier weapons manufacturer during both wo ...

s to

Royal Ordnance L11 The Royal Ordnance L11A5, officially designated Gun, 120 mm, Tank L11, is a 120 mm L/55 rifled tank gun design. It was the second 120 mm calibre tank gun in service with British Army, the first of which was the Royal Ordnance OQF 120mm ...

M777 The M777 howitzer is a British towed artillery, towed 155 mm artillery piece in the howitzer class. It is used by the Australian Army, ground forces of Australia, Canadian Army, Canada, Colombia, Indian Army, India, Saudi Arabian Army, Saudi Ar ...

). The obturating ring provides the sealing that would normally be provided by a

cartridge case A cartridge, also known as a round, is a type of pre-assembled firearm ammunition packaging a projectile (bullet, shot, or slug), a propellant substance ( smokeless powder, black powder substitute, or black powder) and an ignition device ( pr ...

References

81 mm mortar shell information
showing the obturating ring Artillery components

Ballistics uses

See also

References