page_title: Sabot (firearms)
section_title: Ring sabot
hierarchical_section_title: Sabot (firearms) / Types / Ring sabot
caption_attribution_description: 125mm BM15 APFSDS round.
context_page_description: A sabot is a structural device used in firearm or cannon ammunition to keep a sub-caliber flight projectile, such as a relatively small bullet or arrow-type projectile, in the center of the barrel when fired, if the bullet has a significantly smaller diameter than the bore diameter of the weapon used.
  The sabot component in projectile design is more than simply the relatively thin, tough and deformable seal known as a driving band or obturation ring needed to trap propellant gases behind a projectile, and also keep the projectile centered in the barrel, when the outer shell of the projectile is only slightly smaller in diameter than the caliber of the barrel. Driving bands and obturators are used to seal these full-bore projectiles in the barrel because of manufacturing tolerances; there always exists some gap between the projectile outer diameter and the barrel inner diameter, usually a few thousandths of an inch; enough of a gap for high pressure gasses to slip by during firing. Driving bands and obturator rings are made from material that will deform and seal the barrel as the projectile is forced from the chamber into the barrel.
context_section_description: A ring sabot uses the rear fins on a long rod projectile to help center the projectile and ride the bore, and the multi-petal sabot forms only a single bulkhead ring around the projectile near the front, with an obturator sealing gases from escaping past it, and centering the front of the projectile.  The former Soviet Union favored armor-piercing sabot projectiles using ring sabots, which performed acceptably for that era, manufactured from high strength steel for both the long rod penetrator and ring sabot.  The strength of the steel ring was sufficient to withstand launch accelerations without the need for sabot ramps to also support the steel flight projectile.
caption: Soviet BM-15 armor-piercing round with ring sabot
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