Sub-caliber ammunition

Sabot method

Main article: Sabot (firearms)

The most traditional way to fire sub-caliber ammunition is to fit the projectile with an expendable sabot. The sabot is a device which fills out the missing caliber when the projectile is fired and then leaves the projectile once it has left the barrel. File:Sabot Diagram Example.png|Diagram of the sabot method

Saboted sub-caliber ammunition types

• Armour-piercing discarding sabot (APDS)
• Armour-piercing fin-stabilized discarding sabot (APFSDS)
• Saboted light armor penetrator (SLAP)
• Flechette (not necessarily a sub-caliber projectile)
• Shotgun shell (the wad is considered a sabot in some countries)

Flange method

Main article: Squeeze bore

A common method during World War Two, often called the Gerlich-, Littlejohn- or tapered bore principle, was to fit sub-caliber ammunition with soft metal flanges filling out the missing caliber and then fire them from squeeze bore barrels. Squeeze bore barrels, often found on shotguns (see Choke (firearms)), progressively decreases its bore diameter towards the muzzle, resulting in a reduced final bore. When fired the flanges on the projectile would fold inwards as it travels through the reducing inner diameter of the squeeze bore. File:Squeezebore Diagram Example.png|Diagram of the flange method

Flanged sub-caliber ammunition types

• Armor-piercing composite non-rigid (APCNR)
• Armor-piercing non-rigid (APNR)

Sub-caliber barrel

Main article: Sub-caliber training

A third method is to simply fit a smaller barrel into the original full caliber weapon which then allows the firing of smaller caliber cartridges. This is called sub-caliber training and it is used to lower the cost of training with large caliber weapons by allowing them to fire cheaper lower caliber ammunition and to not put wear on the original barrel.

References

Notes

References

1. Rollof, Yngve. "Artillerimaterielens utvecklingstendenser under senaste decenniet". Tidskrift i Sjöväsendet.
2. (1979). "AMORDLISTA, Preliminär ammunitionsordlista". Försvarets materielverk (FMV), huvudavdelningen för armémateriel.
3. "sfhm-skriftserie_handbok-artilleripjaser-och-eldrorsvapen-1800-2000.pdf".