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  1. #1
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    WW2 6 pounder HE projectiles?

    I am hunting for some information concerning British 6-pounder HE shells in service in WW2. I am mainly interested in the 6 pdr 7 cwt (including naval Molins) and 6 pdr 10 cwt ammunition. What I would like to know is:

    1. The designations of the HE projectiles
    2. Which cases they were loaded into
    3. The weight of the projectiles, plus the weight of HE they contained.

    The only one I have a note of (in this article: http://quarryhs.co.uk/Molins.htm ) is the Mk 10T which weighed around 3 kg, but that's all I know about it.

    This thread contains some great photos, in which it is clear that there was more than one type in service: http://www.bocn.co.uk/vbforum/thread...-(WW1-amp-WW2)

    Thanks for any help!

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    In the table the cartridges marked as M indicate that the HE shell fitted were produced for the 6pr 10cwt gun but in order to fit the 6pr 7cwt gun the cartridge cases had to be modified. These were known as hybrid rounds.
    There may have been other marks but this was the situation by 1955.

    I have got one of the photos upside down and am unable to correct this in this reply so you will have to read these comments with the upcoming photos.
    Last edited by AE501; 6th February 2019 at 03:55 PM. Reason: upside down photo

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    Tony Williams (6th February 2019)

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    Thank you very much, that's excellent!

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    OK, I have now sorted out the info in the above pages and translated it into metric, as follows:

    6pr 7cwt:
    Mark IT: length without (optional) tracer socket: 151 mm; total weight 2.41 kg (inc No. 244 fuze); 102.5 g HE
    Mark VIIT: length 183 mm; weight 2.85 kg total
    Mark XT: length 181 mm; weight 2.98 kg total (inc No. 244 fuze); 186 g HE

    6pr 10cwt:
    H.E. IV.T: Length 198 mm (217 mm over tracer socket); 2.85 kg total; 220 g HE; fuze 241 g
    H.E. V.T: Length 196 mm (215 mm over tracer socket); 2.85 kg total; 227 g HE; fuze 193 g

    N.B. diameter of shells 2.235 inches (56.8 mm),
    driving bands: 58.7 mm (7 cwt), 58.3 mm (10 cwt, and 7 cwt Mark XT)
    So, the 10 cwt projectiles seem straightforward with only very minor differences in the two Marks shown. This info shows that the 10 cwt HE were longer than the 7 cwt.

    N.B. The HE projectile I have in a 10 cwt case (shown in my article I linked to above) is stamped "XT" and is therefore presumably the long 7 cwt, not the correct 10 cwt.

    The 7 cwt are clearer - up to a point: the Mark IT is obviously the "short" one shown in the photos below, the "long" one (still shorter than the 10 cwt) could be the Mark VIIT or the Mark XT.

    There appears to be one 7 cwt HE which is not covered here: the one for the naval Molins gun. Campbell's Naval Weapons of WW2 lists the projectile as 2.72 kg and the MV as 655 m/s. This doesn't appear to match any of the others - does anyone know more?

    Also, on the subject of muzzle velocities: the only figure for the 7 cwt HE I have is 820 m/s. However, it seems unlikely that all of the types, with weights varying from 2.41 through 2.85 to 2.98 kg, would all be fired at the same velocity. Does anyone have figures?

    Photo from Hazord:




    Photo from pzgr40:




    photo from HarryG:


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    Hopefully promised info
    Attached Images Attached Images

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  10. #7
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    Many thanks, again!

  11. #8
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    Information updated: what I am missing now are the muzzle velocities for the different 6pr 7cwt HE loadings.

    6pr WW2 HE: Data from official tables

    In the table the cartridges marked as M indicate that the HE shell fitted were produced for the 6pr 10cwt gun but in order to fit the 6pr 7cwt gun the cartridge cases had to be modified. These were known as hybrid rounds.
    There may have been other marks but this was the situation by 1955.

    6pr 7cwt:
    Mark IT: length without (optional) tracer socket: 151 mm; 2.41 kg (inc No. 244 fuze*); 102.5 g HE (later, 182.5 g)
    Mark VIIT: length 183 mm; weight 2.85 kg total (inc No. 244 fuze*); 188 g HE. Also used in the 6 pr 10 cwt.
    Mark XT: length 181 mm; weight 2.98 kg total (inc No. 244 fuze*); 186 g HE. Also used in the 6 pr 10 cwt.

    * No. 257 fuze also used

    Muzzle velocities not known: one figure of 820 m/s quoted for HE, Mark of shell unspecified.

    Ammunition for the naval autoloading 6 pr 7 cwt Molins gun not yet identified: Campbell (Naval Weapons of WW2) states projectile weight 2.72 kg (that's a straight conversion of 6 lbs – questionable?); MV 655 m/s.

    6pr 10cwt:
    H.E. IV.T: Length 198 mm (217 mm over tracer socket); 2.85 kg total; 220 g HE; fuze 241 g
    H.E. V.T: Length 196 mm (215 mm over tracer socket); 2.85 kg total; 227 g HE; fuze 193 g

    Information from Campbell (Naval Weapons of WW2):
    Projectile weights 2.85 or 2.97 kg; muzzle velocities 727 or 718 m/s respectively.

    N.B. diameter of shells 2.235 inches (56.8 mm),
    driving bands: 58.7 mm (7 cwt), 58.3 mm (10 cwt, and 7 cwt Mark XT)

  12. #9
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    Now for some critical thoughts and reality checks!

    6pr 7cwt Mark IT HE: the latest table posted above gives the HE weight as 182.5 g, compared with 102.5 g in the previous table. Given the shorter shell body, does it seem likely that it could have been stuffed with virtually the same weight of HE as the Mk VII and Mk X? Nope. I'm inclined to stick with the 102.5 g weight unless further proof becomes available.

    6pr 7 cwt naval Molins HE: does it seem likely that this weighed 2.72 kg as listed in Campbell, implying a purpose-designed shell? Given that there was a choice of existing HE shells available, one of them would surely have been picked - probably the 2.85 kg Mark VII or 3 kg Mark X.

    6pr 10cwt: given that the case was loaded with 7cwt HE shells (the Mk VII and Mk X) which presumably replaced the original shells on the assembly line at some point, do we know what the original 10cwt shells looked like? Did any of them survive?

  13. #10
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    Some more information about the 6pr 10cwt shells, from drawings and tables (thanks Norman!):

    Several drawings are dated in 1932, obviously at the time the ammo was being developed, as follows:

    No. DD(L) 5477, 7/4/32: No. 131 fuze, total weight 2.72 kg, HE (Lyddite) 243 g
    No. DD(L) 5477.A, 7/11/32: No. 44 fuze (standard for this shell)
    No. DD(L) 5477 A/1, 7/11/32: No. 44 fuze, total weight 2.85 kg, HE (Lyddite) 220 g
    No. DD(L) 5477 B, 23/12/32: No.? fuze, total weight 2.72 kg, HE (Lyddite) 230 g
    The Mark 44 fuze had a different diameter from the later Mark 244, so not interchangeable.

    Data from a table, published long after WW2:
    Mk 4T with Fuze No.44; Lyddite 220 g; total 2.85 kg
    Mk 5T with Fuze No.242; TNT/RDX 227 g; total 2.85 kg
    Mk 6 with Fuze No.242; TNT/RDX 227 g; total 2.78 kg
    Mk 7 with Fuze No.244; TNT 186-188 g; total 2.85 kg
    Mk 10T with Fuze No.244; TNT/RDX 186 g; total 2.97 kg

    The Marks 4T and 5T seem to be the original ones, developed in the early 1930s.
    I'm not sure about the Mk 6
    The Marks 7 and (especially) 10T are the ones used in the 6pr 7cwt.

    The table states an MV with the Mk 10T of 700 m/s, but nothing for the others.

 

 

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