6pdr ammunition

[John McGillivray]

Here are some photos of 6 pounder rounds. The first is of the AP rounds, followed by the APDS rounds. The last photo shows the HE shell.

Was there a difference between the 6 pounder rounds used in the 6pdr Mk.II (Mk.III tank gun) and the 6 pdr Mk. IV (Mk. V tank gun)? The Mk. IV gun had a longer barrel with a muzzle break, which seems to point towards a larger propellant charge. Is this true? If so what was the details.

[Gunner]

Hi John:

The best source I have for this is Hogg's book, "British and American Artillery of WWII". I find my copy tonight and read up on it for you.

Best I remember there was no difference between the ammo used by tankers and anti-tankers (Aunty Tankers was a lovely old gal but she drank alot! )

There was likely a small difference in propellant charge for different weight projectiles to keep the EFCs and recoil wear about the same. Anyway, I speculate... better to read and get it right!

Cheers! Mike

By the way, are there captions to go with those photos? I'm building up a display to go with our gun and would like to add those photos.

[servicepub (RIP)]

I like to think that pages 6 & 7 of "The 6-Pounder Anti-Tank Gun in Canadian Service" describes 6-pdr ammo quite nicely.

[Mark W. Tonner]

Originally posted by servicepub
I like to think that pages 6 & 7 of "The 6-Pounder Anti-Tank Gun in Canadian Service" describes 6-pdr ammo quite nicely.

John;

.............sounds like a sales pitch to me..........

[servicepub (RIP)]

Sorry, was I too subtle??

[servicepub (RIP)]

It isn't ammo but here is a nice drawing of a 6-pdr.

[John McGillivray]

The caption for the first photo is only “British anti-tank gun under fire”. It is from “World War II A Complete Photographic History” Hal Buell editor.

For the second photo the caption reads “A ‘loader’ inserting a round”. The source is the book “Breaking the Panzers The Bloody Battle for Rauray Normandy, 1 July 1944” by Kevin Baverstock. This book deals with the role of the 1st Tyneside Scottish, The Black Watch (RHR) during the battle of Rauray. It has a lot of detail concerning the 1st TS’s anti-tank platoon and its use of APDS ammunition. The platoon KO’ed ten German tanks during this engagement, with No. 3 detachment accounting for five.

The number of German tanks KOed should have being higher, however, because of the total lack of training or instruction on the new ammunition, the gunners often missed their targets.

From page 126-127:

“The 6-pounder had plenty of ammunition near it, and so I loaded one of the recently issued Super Velocity Discarding Sabot rounds into the breach and passed on the corporal's fire order which was, I believe: 'Enemy tank, 12 o'clock, range 400, fire!'. If my memory as regards the range is faulty, it is not respecting the rest of the order. We fired this round, which obviously missed its target as the tank began firing its machine gun or guns at us, the bullets passing all round us and rattling against the gun shield. I now realise why we missed and carried on missing our target, as we set a range on the gun's range scale which should not have been done with this Sabot ammunition. Indeed, when the 1st Tyneside Scottish anti-tank platoon was given its first issue of the Sabot rounds in early June 1944, we were not instructed, as we should have been, to fire them with our range scales at 'T, i.e. no range, and I think the same must have happened with the 6th KOSB, thus the corporal should have ordered us to set the range at 'T'.

“LtB.T.W. Stewart, 2nd i/c, Anti-tank Platoon, 'S' Company, 1st TS:
The 'miracle' Sabot rounds were much, much faster in flight, and the tungsten 'dart' which emerged was able to penetrate much thicker armour. However, the extra velocity seriously affected our range finding and the need to lay off for speed. The new ammunition had a different trajectory, which is of course self-evident - flatter trajectory with a greater speed - but we were not told this when the Sabot ammunition was first issued and there were no instructions to accompany it. We simply knew that it was more effective, which it proved to be, but we should have taken note of the effects of vastly increased velocity in the art of the aimer. It was unfortunate that we had no opportunity before we left the UK to practice with this new, highly effective ammunition or there would have been more damage done to the enemy.”

The third photo is a capture from a film clip on a DVD. If the film clip was shown in its proper context then it was shot during the battles near Monte Casino in Italy in the spring of 1944.

Clive, I have your book. I picked it up at the CWM last summer. On page 4 it states;

“Mark IV - a longer barrel with a bore length of 112.2 inches (50 calibres). This increased the muzzle velocity, and a muzzle brake had to be fitted to reduce the stress on the towed carriage. Barrels manufactured in Canada were designated "C" Mark IV;”

So the muzzle brake was only added because of the longer barrel, and not because of a change to the size of the propellant charge.

Originally posted by servicepub
It isn't ammo but here is a nice drawing of a 6-pdr.

While it may be a nice drawing of a 6pdr it is obvious that the crew loading the gun on to the landing craft in the background haven't a clue as how to move a 6pdr. Normally the gun commander would drape his body over the muzzel end of the barrel to act as a counter weight thus allowing the rest of the crew to concentrate on moving the gun with less effort in lifting the trail legs. Two men on the draw bar, two men on the drag ropes and the gun commander over the barrel.

The Fire Order sequence leaves something to be desired also.

[Geoff Winnington-Ball (RIP)]

Shouldn't it be loaded backwards too, in order to be towed off the LC?

[Gunner]

Hi Guys:

Firstly, to Clive- sorry chum, no insult intended... as you know, Doug's book is dedicated to me and the museum so I'm very proud of it. I won't tell you how many copies I have purchaed to give to family and friends! For highly technical details about ammo, I tend to defer to Master Gunner Hogg. Mea Culpa!

For John: Hogg indicates that the 6 pounder used 2 pounds, five and 1/4 ounces of cordite plus or minus 1/4 ounce depending on the projectile. The US 57mm ammo used NH (non-hydroscopic) propellant which wasn't as "hot" and so had somewhat more propellant in each casing. This played hell with ballistic tables for a while when the US sent bulk stocks of NH without warning the UK of the difference. Reading between the lines, the UK stuck with cordite for high velocity guns and used the NH for other purposes (howitzers?). More research needed here.

This ballistic issue could also bring into question the recorded memories of Lt Stewart as the APDS round may be going faster, but how much? It is smaller, thus the imparted energy on the target is greater. Its all a function of same amount of powder moving a lighter and smaller projectile. I'll do some more digging to see if I can find MVs for the different rounds.

Geoff: Loading the guns trail first might make sense if they were going to be pushed out and deployed right away. Towing out would require an "Action Front" and spinning the gun 180 degrees.

Art: I thought the same thing... we never move our 6 pounder without draping someone over the muzzle as a counter weight. The tongue weight is just a bit too much for me old back and safety dictates that we make it as easy as possible on the detachment.

Cheers!

Mike

[Gunner]

Hi John:

Properly chastised by Clive, I got into my copy of Doug Knight's book.

The MV for AP was about 2600 fps for a six pound projectile and for APDS almost 4100 for a 2 1/2 pound projectile. Nearly 1.6 times faster.

Getting back to the original question regarding the propellant charge; I'm now certain that the charge remained the same and the higher velocity was all due to the lighter weight of the projectile. Lt Stewart is vindicated as he only spoke of velocity not propellant... my apologies if I appeared to cast aspersions on his memory.

On the "felt" recoil with the longer barrel, it is interesting to note that the US 57mm M1 had the same length barrel as the Mk IV gun yet they never fitted a muzzle brake. More reading required!

Mike