World Library  
Flag as Inappropriate
Email this Article

17pdr SP Achilles

Article Id: WHEBN0018777844
Reproduction Date:

Title: 17pdr SP Achilles  
Author: World Heritage Encyclopedia
Language: English
Subject: World War II tank destroyers, World War II tanks of the United Kingdom, Allied technological cooperation during World War II, Coventry armoured car, Grizzly I cruiser
Publisher: World Heritage Encyclopedia

17pdr SP Achilles

17pdr SP M10 "Achilles"
"Achilles" Self-Propelled Gun M10 at La Roche-en-Ardenne, Belgium
Type Self-propelled anti-tank gun
Place of origin United Kingdom
Production history
Manufacturer converted by Royal Arsenal, Woolwich
Number built 1,100
Weight 29.6 tonnes (65,000 lb)
Length 7.01 m (23 ft 8 14 in) including gun
5.97 m (19 ft 7 in) excluding gun
Width 3.05 m (10 ft)
Height 2.57 m (8 ft 2 in)
Crew 5 (commander, loader, gunner, loader's assistant, driver)

Armour 9 to 57.2 mm (0.3 to 2.3 in)
Ordnance QF 17 pounder (76.2 mm)
50 rounds
.50 cal Browning M2HB AA machine gun
420 rounds
Bren light machine gun[1]
Engine General Motors 6046 diesel (conjoined twin 6-71s)
375 hp (276 kW)
Power/weight 12.5 hp/tonne
Suspension Vertical Volute Spring Suspension (VVSS)
300 km (186 mi)
Speed 51 km/h (32 mph)

The 17 pounder, Self-Propelled, Achilles was a British variant of the American M10 tank destroyer armed with the powerful British Ordnance QF 17 pounder anti-tank gun in place of the standard 3" (76.2 mm) Gun M7. With a total of 1,100 M10s converted, the 17 pdr SP Achilles was the second most numerous armoured fighting vehicle to see service armed with the 17 pounder gun, behind the Sherman Firefly.

The name "Achilles" was officially a designation applied to both the 3" gun and 17 pounder versions (as Achilles I/II and Achilles Ic/IIc respectively) but was little used during the Second World War; at the time, the vehicle was called 17pdr M10, or 17pdr SP M10, or even occasionally, "Firefly". It has since become identified almost exclusively with the 17 pounder version.


In the wake of Germany's successful 1939–41 campaigns, US armour doctrine had incorporated the idea of fast, lightly armoured vehicles carrying high velocity anti-tank guns as the best way to deal with the fast moving armour spearheads of the German Blitzkrieg. The M10 was based on the chassis of the M4 Sherman but carried thinner although more sloped armour in order to comply with the high speed requirement for the tank. At the same time, the British had been examining the possibility of designing a low-silhouette self-propelled tank destroyer, preferably with a 360-degree traversing turret, with armour that would be able to resist the German 50 mm at 800 yards and mounting the 17 pounder. However with the arrival of the M10 on the battlefield in late 1942, British plans for a turreted self-propelled gun were cancelled.

The M10 was first made available to the British in 1943. These vehicles were open-topped and mounted a 3-inch American gun, which was significantly more powerful than the Ordnance QF 6 pounder that was mounted on British tanks of the period and was of equal power to the 7.5 cm KwK 40 used by the Panzer IV and Sturmgeschütz III. When introduced into service in late 1942, the thin but sloped armour of the M10 provided good protection against the standard 50 mm gun mounted on most German tanks and anti-tank guns, and the 3-inch (76 mm) gun was able to easily defeat all German armour except for the handful of Tigers deployed against the Western Allies.


An Achilles 17pdr tank destroyer crossing the River Savio on a Churchill ARK which was driven into the river, 24 October 1944

The 17 pdr SP Achilles was basically a modified M10, the main difference being the gun. The main armament of the Achilles was the Ordnance QF 17 pounder, a gun with greatly superior anti-tank performance over the standard American 3" anti-tank gun. The single top mounted M2 Browning HMG was retained.

The 17 pounder mounted on the Achilles was able to penetrate some 140 mm of armour at 500 m (550 yd) and 131 mm at 1,000 m (1,100 yd) using standard Armour Piercing, Capped, Ballistic Capped (APCBC) ammunition impacting at a 30-degree angle. When supplied, Armour-piercing discarding sabot (APDS) ammunition could penetrate some 209 mm (8 inches) of armour at 500 metres and 192 mm at 1,000 metres at a 30-degree angle. In comparison the 3-inch (76 mm) gun on the standard M10 using the same type of ammunition (APCBC) would penetrate 98 mm of armour at 500 m at a 30-degree angle, and 88 mm of armor at 1,000 meters at a 30-degree angle. Only with High Velocity Armour Piercing (HVAP) ammunition did the 3-inch (76 mm) gun compare with the 17 pounder, the ammunition being able to penetrate 140 mm at 500 m at a 30-degree angle, and 127 mm at 1,000 m at a 30-degree angle. However HVAP ammunition was in very short supply and it only just compared with the standard 17 pounder ammunition that was available in huge amounts for the British.

The 17 pounder required a counterweight fitted behind the muzzle brake on its long barrel. This gave the Achilles a distinctive appearance compared to the M10 and there were attempts to disguise this by painting the brake and counterweight.

The only other change carried out on the Achilles was the addition of 17 mm (0.67 in) thick armour plates welded to the front and sides of the M10 to increase armour protection, as well as a 20 mm thick shield fitted to the top of the turret to provide protection from overhead threats that resulted from the M10 having an open top turret.


Crossing the Rhine 24–31 March 1945: An Achilles self-propelled anti-tank gun on the east bank of the Rhine moves up to link with airborne forces whose abandoned Horsa gliders can be seen in the background. 26 March 1945

The desire to mount the 17 pounder on the M10 was governed by the degree of difficulty involved in mounting the 17 pounder on the tank itself. Luckily for the British, the initial batches of M10s had an easily modified gun mounting to facilitate the future replacement of the older 3 inch M7 gun with the newer 76 mm gun M1. This gun mounting design allowed for the British to replace the 3 inch gun with the 17 pounder gun. The British took delivery of some 845 vehicles in 1943, but of the second version of the M10, only the T71 mark could carry the 17 pounder, the T70 mark being designed to only allow the lighter American 76.2 mm M1 gun.[2]

The British had planned to convert some 1,000 M10s into 17pdr armed variants for Normandy, but for some reason conversions were not started until April 1944. By D-Day only some 124 M10s had been converted, however the number of conversions post D-day increased and by the end of the year 816 M10s had been converted, 152 vehicles in November alone. However the low numbers at D-day meant that many British units went ashore fielding standard M10s rather than 17 pounder armed Achilles, and losses in Achilles units could at times be hard to replace, the crews receiving regular 3" armed M10s as replacements for their lost 17 pdr Achilles much to their dismay.

As a self-propelled anti-tank gun, Achilles as well as standard M10s were distributed to and operated by the regiments of the Royal Artillery. Around 1,650 M10s were received by the British during the war, of these 1,100 were converted to the 17 pdr by the end of the war.

Operational use

An Achilles of 245 Battery, 62nd Regiment, Royal Artillery, knocked out in Normandy, 1944. Three penetrating hits are visible on the turret.

Unlike the Americans, who saw the M10 as a tank hunter once it became clear that the Germans had gone on the defensive, the British still viewed the Achilles as a mobile anti-tank gun. The standard anti-tank gun used in infantry units in the British Army was the 6 pounder anti-tank gun, a small, light gun able to defeat the more common German Panzer IV and Sturmgeschütz with regular ammunition but not the heavier Tigers and Panthers. The next generation British gun, the 17 pounder anti-tank gun, was able to deal with Tigers and Panthers but took a far longer emplacement time than the 6 pounder due to its larger size, often taking a day to fully emplace and prepare for action.

17pdr SP Achilles of the Battle of the Bulge in La Roche-en-Ardenne.

As a result, the British used the Achilles as a quickly deployable anti-tank gun, able to reinforce a position taken by infantry and engage counter-attacking German forces while the slower towed 17 pounders were pulled up and dug in for a more long-term defensive presence. This had the advantage of mitigating the weak armour protection of the Achilles as being used defensively usually allowed it to fire the vital first shot. This was in line with the original design concept of the vehicle, intended to blunt German "blitzkrieg" attack tactics. The M10/Achilles turret had an extremely slow manual only turret rotation, but this was not a significant tactical limitation when the tank was used in its "proper" defensive role. In this role it was clearly superior to German Stugs which had no turret rotation. The Stug's were more successful in any event in the east due to a different tactical environment where their low profile and heavy armor was a significant asset. Usually, the only time the British used the M10 and Achilles offensively was in support of Churchill tank units as they did not have associated 17 pdr armed tanks like Sherman and Cromwell tank troops did.

Achilles went ashore on D-Day, equipping units of the Royal Artillery and Royal Canadian Artillery in Armoured Division or Corps Anti-tank Regiments. A typical A/Tk Regiment would have 4 Batteries, 2 x Towed 17 Pdr Batteries, 1 x Achilles and 1 x M10 Battery. The M10 Battery was replaced by a second Achilles Battery as more vehicles became available. Perhaps the most successful action of the Achilles was conducted by B troop, 245th Battery, 62nd Anti-Tank Regiment, Royal Artillery attached to the Hamilton Light Infantry during Operation Charnwood. South of Buron, a counterattack by a mixed force of Panzer IV and Panther tanks of the 12th SS Panzer Regiment was defeated by Achilles and 17-pounder anti tank guns of 245th Battery, 62nd Anti-tank Regiment. Thirteen German tanks were destroyed in one of the most successful antitank engagements of the campaign, for the loss of four self-propelled guns and a further four damaged.[3]

See also


  1. ^ Chris Henry, Brian Delf British Anti-tank Artillery 1939–45, p. 24.
  2. ^ Buckley, J. "British Armour in the Normandy Campaign" Abingdon (2004) p. 171
  3. ^ Copp (2003), pp. 103–104, 296–297


  • British Anti-tank Artillery 1939-45 By Chris Henry, Brian Delf at google books

External links

This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from Hawaii eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.