Obturating ring

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title: "Obturating ring" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["artillery-components"] description: "Ring of soft material designed to obturate under pressure" topic_path: "general/artillery-components" source: "https://en.wikipedia.org/wiki/Obturating_ring" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Ring of soft material designed to obturate under pressure ::

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 and other ballistics applications, and similar devices are also used in other applications such as plumbing, like the olive in a compression fitting. The term "O-ring" is sometimes used to describe this kind of pressure seal.

Ballistics uses

::figure[src="https://upload.wikimedia.org/wikipedia/commons/8/88/305_mm_breech_Maneesi_1.JPG" caption="Welin screw breech block]]{{cite web"] ::

|title=12 inch Mk X Gun Breech Mechanism : HMAS Australia (I) |url= https://www.awm.gov.au/collection/C240739 |website= Australian War Memorial |url-status= live |archive-url= https://web.archive.org/web/20250826235636/https://www.awm.gov.au/collection/C240739 |archive-date=2025-08-26 |access-date=2025-08-26 |quote=The mechanism consists of the breech, and an interrupted screw breech block on a hinged mounting. [...] The Welin breech block was invented by Axel Welin in 1889 or 1890.}} showing the protruding head of the mushroom-shaped de Bange obturator, with its obturating ring between the head and the screw]] 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 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 rifles and some artillery use rings with a reverse impression of the rifling cut in them for a tighter seal even at very low pressures.

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 guns to Royal Ordnance L11 to M777). The obturating ring provides the sealing that would normally be provided by a cartridge case.

References

• 81 mm mortar shell information, showing the obturating ring

::callout[type=info title="Wikipedia Source"] This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page. ::