Talk:Ordnance QF 6-pounder

APCBC is not related to APCR

Maury you have it a bit mixed up. Evolution of armour piercing rounds runs something like AP -> solid steel shot, against face hardened armour it's possible to shatter the nose of such a round, solution: APC -> solid steel shot with a soft meal cap to support the nose on impact, down side of this is it's not aerodynamic and it decreases penetration of RHA, this leads to APCBC -> as for APC but with a very light aerodynamic cover over the nose, still not as good as APC against RHA but has a better ballistic coefficient and so retains velocity at longer ranges.

Now along comes a new idea a metal heavier than steel is better at penetrating armour than steel is, down side it is heavier so you can't get it moving as fast without drastically increasing the pressure inside the gun, solution: put the heavy metal slug (tungsten, uranium, etc) inside a light weight container that will fit a larger gun so overall it's weight is the same or less than the round the larger gun would ordinarily fire, result: APCR (which if things were named consistently would probably be APS Armour Piercing Sabot), downside of this is that the carrier gets dragged along to the target slowing the whole round down reducing penetration at long range, solution allow the sabot to fall away after leaving the muzzle -> APDS.— Preceding unsigned comment added by 144.134.252.30 (talk) 04:57, 9 December 2005 (UTC)

"APCBC" = Armour Piercing, Capped, Ballistic Capped

"APCR" = Armour Piercing, Composite, Rigid

The concept of using a larger-diameter 'shoe' (sabot) around the shot originated with the French, however while improving the penetration, this resulted in lowering of the range, the (lighter) shot with the sabot attached suffering from the same aerodynamic drag as the normal-sized shot while weighing less. After the Fall of France in 1940 Permutter and Coppock of the Projectile Development Establishment at Fort Halstead in the UK then devised a form where the sabot was discarded upon leaving the barrel, and this became APDS. Permutter was a Belgian who had formerly worked for the Brandt company. IIRC, the original French sabots were of light alloy, whereas the British APDS ones were (at least for a time) Bakelite.

Initial tests on APDS revealed a tendency for parts of the sabot not to separate cleanly upon leaving the bore, and so the clearance between the sabot and shot was increased, solving the separation problem, however it was then discovered that accuracy was variable, some test rounds good, others poor. This took a while to solve, it was eventually deduced that the now more loosly-fitting sabot was not transferring the full spin imparted by the rifling to the sub-projectile. The clearance between shot and sabot was then adjusted, solving the accuracy problem. The rounds were then cleared for production and issued to units in IIRC 1944.

The arrival of APDS for the 6 pdr was the reason it remained in service until the end of the war, as it was still a very useful weapon at moderate ranges against even the larger German tanks such as the Panther and Tiger I and Tiger II providing it could be brought to bear against the vehicle sides or rear. IIRC, APDS completely replaced all other UK tank gun anti-tank rounds with the arrival of the 105mm L7 - although still useful against armour HESH was by then mainly intended for infantry support as fired through a door or window it would clear a building of personnel quite nicely.— Preceding unsigned comment added by 95.150.11.221 (talk) 09:15, 18 March 2018 (UTC)

Corrections!

By Aburger

I made the initial post with the penetration figures, sorry about there disorganisation.

Just to make a few of my corrections to the apcbc is not related to to apcr.

Its better than apc against rha, its just not as good against fha. Apcr stands for armour piercing composite rigid and your description is spot on.

Some more info for interest the 6 pounder apcbc penetration figures should be revised to 105mm at 100 yards (30 degree angle of impact) as mackay's book tank battle's qoutes it as being able to pen the tiger hull frontaly at this range. Also I know have a digital copy of WO 185/118 D.F.V.G Which has the steel Ap round from the 50 calibre gun penetrating the Drivers front plate of the tiger from 700 yards. Aburger

Maybe the 6 pounder penetrates the front of the Tiger because it's practically at zero degrees. It could have a penetration of 105mm at 100m at 0 degrees (perpendicular), and 95mm at 100m at 30 degrees from the vertical. User:ATK102587

Apcr began production in june but heavier production began in october 43, presumably because of the italian invasion. It was cancelled shortly after apds production began in march 44. (Ian Hogg's British and American Anti tank Artillery ISBN 1853674788)Aburger

The Churchill Claim was taken from the Churchill Infantry Tank by Bryan Perrett & M. Chappell Osprey Publishing ISBN 9781855322974. Aburger

"HEADQUARTERS 776TH TANK DESTROYER BATTALION APO #758 11 December 1944 EFFECTIVENESS OF FIRE OF 57 MM ANTI-TANK GUN ON MK V TANK is the source for the claim penetrating the Panther turret found at this website http://www.efour4ever.com/57mm.htm Aburger

The 17 Pounder did not replace the 6 pounder in Royal anti tank regiments At Regiments had a full organisation of 110 guns, 32 17 pounders and 68 6 pounders. British Anti-tank Artillery 1939-45 By Chris Henry ISBN 1-84176-638-0 Aburger— Preceding unsigned comment added by 86.134.13.220 (talk) 18:37, 5 February 2006 (UTC)

For some reason the US did not issue the 57mm with any additional ammunition other than the normal AP round, however in Normandy and later some US units were able to obtain 6 pdr APDS rounds from British units.

Measurements and dimensions

Either I'm misreading the quoted figures, or there's a typo. 2.82 metres seems way too short for the overall length, since even 43 calibres is over 2.4 metres. Find a good side view and the proportions look wrong.

It's certainly not the overall length, but just what is it the length of? —The preceding unsigned comment was added by 88.109.55.113 (talk) 14:46, 7 February 2007 (UTC).

Probably the barrel and breech together which is strictly the QF 6 pounder part, the carriage being defined separately. GraemeLeggett 14:56, 7 February 2007 (UTC)

The carriage weight is what the 7 cwt refers to in the full designation - something like; Ordnance QF 6 Pounder on Carriage 7 cwt. — Preceding unsigned comment added by 80.7.147.13 (talk) 18:16, 2 June 2013 (UTC)

Let's see what books say...

• Hunnicutt (Sherman):
  • Mk II barrel: bore length 42.9 cal / 96.2 in / 2443 mm; overall length 45 cal / 100.95 in / 2564 mm.
  • Mk IV barrel: bore length 50 cal / 112.2 in / 2850 mm; overall length (without m/b) 52.1 cal / 116.95 in / 2971 mm.
• Hogg (Allied Artillery of World War II), Mk II: burrel length 100.95 in / 2564 mm, barrel weight 348 kg, weight in action 1143 kg.
• Foss (Artillery of the World): length 4724 mm, width 1889 mm, height 1280 mm and weight in traveling position 1224 kg. But for which Mk ?

Bukvoed 16:21, 7 February 2007 (UTC)

Sketch of the 6-pounder Mk 2

Why couldn't this image be uploaded on Wikipedia or Commons as {{PD-USGov-Military-Army}}? It's published in WWII U.S. War Department Special Series. Ain92 (talk) 15:21, 15 June 2012 (UTC)

Penetration for APCBC vs. APCR

just for a note. according to information from robert livingston(read in a book i forgot the name. the 6 pounder used in normady with apcbc, penetrates 120mm at 0deg, and 95mm at 30 deg at 100 yds; and does 101 at 0deg, 80mm at 30deg at 1000 yds.

apcr is accrding to A memo from the Ministry of Supply dated 1st April 1943 gives the following figures for "Single homo (taken from a document made by john d salt from www. britwar.co.uk) plate penetration at 30º in mm.": 500 yds 1000 yds 1500 yds. 6-pdr APCBC 86.5 79.8 73.5. 6-pdr Littlejohn 123 111 101. 6-pdr composite rigid 109 90 75.(apcr). Taken from the 1975 bovington fire and movement booklet.

APDS    100m 500m 1000m 2000m.
         131  117   103   90. 

All figurea are british standard of 50% of hits penetrating plate of a bhn approximatly 278.

Excellent numbers, although in their current form they are a little disorganized. I'll try getting this to format correctly...

            100yrd  500yrd  1000yrd  1500yrd
APCR                109      90       75
APCBC       95       87      80       74
APDS        131     117     103       90
Littlejohn          123     111      101
mm of penetration of homogeneous steel armor at 30 degrees angle

What is odd about this list is that the APCBC are smaller than the APCR numbers. I was under the impression that the APCBC rounds were a minor variation on APCR that further improved its ballistics. The fact that it replaced APCR (I think) in service also suggests it's numbers should be higher, not lower. And certainly not this much lower! Maury 13:39, 17 November 2005 (UTC)

APCR = Armour-Piercing, Composite-Rigid.

APCBC = Armour-Piercing, Capped, Ballistic-Capped. — Preceding unsigned comment added by 95.150.10.245 (talk) 18:33, 2 January 2017 (UTC)

The 'capped' shot (APC) was a standard AP projectile fitted with a softer nose cap intended to prevent the very-hard but brittle projectile shattering upon impact, whereas the 'ballistic cap' was a later development fitted over the cap to improve the projectile's streamlining, and hence range as the best armour-penetrating shape is not the best shape aerodynamically. APCBC had both types of cap. IIRC APCR had a hardened, rigid tip fitted to the AP projectile intended to achieve the same purpose.

Both APCR and APCBC were devised to prevent the projectiles shattering upon impact with the ever increasing muzzle velocities then being used to defeat increasingly heavier armour.

IIRC, APC and APCBC ammunition had originally been devised for the heavy guns of Battleships, possibly after the Battle of Jutland when some British heavy shells were shattering upon impact rather than penetrating.— Preceding unsigned comment added by 95.149.173.73 (talk) 10:28, 5 February 2019 (UTC)

Conflicting Views Perhaps

Just so I am not missing anything; in the penetration tables it states that British AP could penetrate 135mm of what I am guessing is RHA. Thus, the quote from 'Service History', 'British Service' 'Anti-tank gun' it says that, and I quote "The standard 6-pounder shot was ineffective against the front armour (of Tiger and Panther tanks) at any range..." If the armour of the Tiger 1 was 100mm thick, surely it cold penetrate the front of the Tiger at ranges below 500m.

The 6-pdr using APDS shells could penetrate a Tiger or Panther.

2A01:4B00:881D:3700:9855:B4FF:68DD:F753 (talk) 13:01, 3 January 2020 (UTC)

There are several places for flaws in my logic: 1) The word "ineffective" is a broad term, and doesn't refer to the inability of British 6-pdr AP to penetrate the armour of the Tiger 1 tank frontally. 2) The armour of the Tiger 1 is of a different rating, or not comparable to the penetration for British 6-pdr AP. 3) The 135mm value for the penetration isn't referring to RHA. 4) The figures for the Tiger 1's frontal armour is not a RHA figure.

Other than that, I would like to see a source listed for the quote "The standard 6-pounder shot was ineffective against the front armour at any range," so it has better reference value. If not, then perhaps the flaw in my logic listed above - or otherwise - should be made a note around the penetration tables.

The penetration table is an estimate based upon calculations to turn measured performance (in the case of British guns firing at an angled plate) into a standardized form (90° to line if shot). And part of that format is that the shot succeeds 50% of the time. GraemeLeggett (talk) 12:09, 25 May 2019 (UTC)

Service history

It says: In service 1942–1960. Yet under that is say it served in the Indo-Pakistani war of 1971. The Service history was when the last gun was in service in any army. 2A01:4B00:881D:3700:9855:B4FF:68DD:F753 (talk) 11:44, 2 January 2020 (UTC)

Tsetse fly

On the de Havilland Mosquito page the rounds carried is referenced at 25 yet this article states 21 & I really can't be arsed arguing the toss when I'm only trying to be consistent, change both BAM but let's not leave it different. Steve Bowen (talk) 09:37, 30 October 2020 (UTC)

Verifiability is the key here. You can check Williams quite easilyTHE 6 PDR 7 CWT AND THE MOLINS GUN. Someone might have mistyped from Bowman on the Mossie page. Or someone might have edited the page after the Citation was added. GraemeLeggett (talk) 14:07, 30 October 2020 (UTC)

Sourced to page 165 of this book: Bowman, Martin. de Havilland Mosquito (Crowood Aviation series). Ramsbury, Marlborough, Wiltshire, UK: The Crowood Press, 2005. ISBN 1-86126-736-3. Under the principle of assuming good faith we assume that the source supports this figure see the section on the Mossie talk page, but as I said I really can't be Arsed... Steve Bowen (talk)