# L15 (shell)

**L15** was a British 120 mm armor-piercing discarding sabot (APDS) tank round fired from the L11 series rifled gun, originally fitted to the Chieftain main battle tank. It was the original anti-armor element of the L11 gun's ammunition family, and it used a tungsten alloy shot whose eroding behavior gave it unusually strong performance against sloped and spaced armor for its type.

| Key fact | Detail |
|---|---|
| Type | Armour-piercing discarding sabot (APDS) round for the 120 mm L11 series rifled tank gun<sup>[1](https://cdck-file-uploads-us1.s3.dualstack.us-west-2.amazonaws.com/flex016/uploads/cartridgecollectors/original/3X/1/a/1a1483e22e0f2a9d33d2f3337f63ac500fd9a1b6.pdf)</sup> |
| Primary gun and tank | L11 on the Chieftain; also carried in the original ammunition fit of Challenger 1<sup>[2](https://uwnetwork.wordpress.com/2010/06/22/a-short-history-of-the-uk-development-of-du-anti-tank-ammunition/)</sup> |
| Kinetic energy | Over 7 MJ at the muzzle, higher than most 125 mm APFSDS projectiles<sup>[3](https://www.youtube.com/watch?v=GL5uPxVE2nk)</sup> |
| Reference penetration | L15A5 could defeat the "NATO Heavy Target", 140 mm of rolled homogeneous armor at 61 degrees, at 2000 yards<sup>[3](https://www.youtube.com/watch?v=GL5uPxVE2nk)</sup> |
| Successor | The L23 APFSDS fin-stabilized round, developed when L15 no longer sufficed against modern tanks<sup>[4](https://www.kotsch88.de/m_120mm-L11.htm)</sup> |

## Design

The L15 was a saboted kinetic round: a sub-caliber core rode inside the 120 mm bore on a lightweight sabot that fell away after leaving the muzzle, allowing a small, dense projectile to be fired at high velocity from a large gun.

The round's distinctive feature was its core material. The L15's tungsten alloy eroded during penetration, which drastically increased performance against sloped armor; this eroding-penetrator concept remains a characteristic of all modern APFSDS projectiles<sup>[3](https://www.youtube.com/watch?v=GL5uPxVE2nk)</sup>.

## Performance

The L15 left the muzzle at 1370 m/s, a figure consistent with the contemporary American report that the Chieftain's 120 mm APDS round had a muzzle velocity of about 5000 feet per second, giving considerably greater penetration at greater range than the 105 mm gun<sup>[5](https://mcoecbamcoepwprd01.blob.core.usgovcloudapi.net/library/CavalryArmorJournal/1970s/1970Jul-Dec.pdf)</sup>.

In kinetic energy the round was exceptional for its type: over 7 MJ, higher than most 125 mm APFSDS projectiles. Much of that energy was nonetheless wasted in penetration because of the steel shroud and the thickness of the core<sup>[3](https://www.youtube.com/watch?v=GL5uPxVE2nk)</sup>. Against the standard reference plate, the L15A5 could penetrate the "NATO Heavy Target", 140 mm of rolled homogeneous armor inclined at 61 degrees, at 2000 yards<sup>[3](https://www.youtube.com/watch?v=GL5uPxVE2nk)</sup>.

The eroding core also shaped the round's behavior against angled plate.

## Service and replacement

The APDS concept reached its peak with the 120 mm gun fitted to the Chieftain<sup>[6](https://www.arrse.co.uk/wiki/Sabot)</sup>, and the L15 was regarded as the most powerful kinetic round NATO possessed from the mid-1960s to the mid-1970s<sup>[3](https://www.youtube.com/watch?v=GL5uPxVE2nk)</sup>. The round remained in the ammunition fit when [Challenger 1](https://www.edgepedia.org/challenger-1) entered service in March 1983, alongside the more advanced L23 APFSDS, both tungsten based<sup>[2](https://uwnetwork.wordpress.com/2010/06/22/a-short-history-of-the-uk-development-of-du-anti-tank-ammunition/)</sup>.

Its limits were reached against newer Soviet-style armor. When the effect of the L15 proved insufficient against modern battle tanks, a fin-stabilized sub-caliber projectile with sabot petals, the APFSDS type, was developed, beginning with the L23 for the Chieftain's 120 mm L11 gun<sup>[4](https://www.kotsch88.de/m_120mm-L11.htm)</sup>. The L15's eroding-core behavior, however, carried forward into the APFSDS rounds that replaced it<sup>[3](https://www.youtube.com/watch?v=GL5uPxVE2nk)</sup>.

## References

1. [RO Defence 120mm tank gun ammunition, Jane's Defence News](https://cdck-file-uploads-us1.s3.dualstack.us-west-2.amazonaws.com/flex016/uploads/cartridgecollectors/original/3X/1/a/1a1483e22e0f2a9d33d2f3337f63ac500fd9a1b6.pdf)
2. [A short history of the UK development of DU anti-tank ammunition, UK Uranium Weapons Network](https://uwnetwork.wordpress.com/2010/06/22/a-short-history-of-the-uk-development-of-du-anti-tank-ammunition/)
3. [CHIEFTAIN vs IS-4M | 120mm L15A5 APDS Simulation | Armour Piercing Developments Vol. 3, SY Simulations](https://www.youtube.com/watch?v=GL5uPxVE2nk)
4. [Das Panzerdetail: Munition der britischen 120 mm Kanone L11 und L30A1](https://www.kotsch88.de/m_120mm-L11.htm)
5. [Cavalry/Armor Journal, July–December 1970, U.S. Army Armor School](https://mcoecbamcoepwprd01.blob.core.usgovcloudapi.net/library/CavalryArmorJournal/1970s/1970Jul-Dec.pdf)
6. [Sabot, ARRSEpedia](https://www.arrse.co.uk/wiki/Sabot)

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*Topic: Encyclopedia › Technology and the built world › Engineering and manufacturing › Tanks and armored fighting vehicles › Tank guns, armor, and design technology*

*Initially written Oct 15, 2026 · Edited: Oct 25, 2026*

*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*

License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license