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77mm MK1

fert

Well-Known Member
Premium Member
Hi man...
recently found this case, a 77mm MK1 for comet tank.
I would to know some info about. shell used, history of gun, if only tcase was take from the old 3in 20cwt or if was the gun adapted for tanks.
was the tank used in Italy during 44-45? or maybe anything was supply after the war?
last question, could you read the stencilling on the base?
best regards
 

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77M/M Mk1 = The weapon
VAEL = Monogram of case manufacturer; Vickers Armstrong, Ltd., Elswick
Lot 295 = Manufacturing Lot
1945 = Year of manufacture
CR = Charge, Reduced, as opposed to CF: Charge, Full (from what I can ascertain the majority of 77mm was Charge, Reduced with the exception of the APDS round which is the projectile you have!

Not my area of knowledge, but it would appear the 77mm used the same projectile as the 17 pdr but used the case of the 3" 20CWT. The weapon was a fresh design.

Tim. G.
 
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I agree with most of the above.

Charge reduced would be for the H.E. and practice loadings.

The Comet tank was only used in action during the the last few months of WW2 by the 11th Armoured division in north west Europe.

Projectiles are marked 17 Pdr & 77mm, but i dont know if projectiles only marked 17 pdr could also have been used?

Quatermass
 
Strangely Q, when I looked in my Comet ! Armament Handbook I was surprised to find the diagrams of the
APCBC/T
HE/T
HE/HC/T
HE/Super/HC/T
Are all depicted as having 'CR' headstamps. However, the APCBC/T is not annotated as 'Reduced charge' whereas the rest are.

Tim. G.
 
H.E. rounds with a full charge tended to either dig themselves in the ground or ricohet of the target before the fuze had time to operate.

I have a 77mm case stencilled for APCBC with a CF stamp.

Quatermass
 
Chaps, being one of my fav rounds, I happen to have 3 of these cases, all 1944/45 dated.

APDS round in Case with CF 1945 and APDS on base
APC round in Case with CR 1944 and APC on Case
APCBC round in Case with CF 1945 and no markings.

My curiosity surrounds the APC case and projectile. The projectile is almost identical to an APCBC projectile, except the "ballistic cap" is solid and not hollow. Secondly, I am somewhat surprised that the 77mm MKI didnt skip the APC round altogether.

Any Ideas anyone?

Rich
 
Good question Richard, Id guess that the APC round had slightly better penetrating power at short range compared to the APCBC.

The ballistic cap would actually degrade the penetrative performance of the projectile at short range, an advantage only being achieved on medium to long ranges.

Quatermass.
 
With your actual specimens I was about to accuse the illustrator of getting carried away drawing 'CR' on the bases. However, on browsing the manual further. I found the 'EFC values' which for APCBC shows;
1 full charge = 1.0
1 reduced charge = 0.03
I can only conclude from this that the APCBC round came in two flavours; full and reduced charge. This seems rather strange as penetration is related to kinetic energy, is related to velocity, is related to charge. Of what benefit is an AP shot set to 'stun'? There is nothing to suggest the reduced charge round is a practice round.

Tim. G.
 
I have had a quick look at a 1947 Tech Ammo letter on the 17 pr and it notes that the projectiles for the 77mm gun and the 17 pr were interchangeable and that it was at the beginning of 1944 that they marked them '17 pr and 77mm' as part of the nomenclature. I think I have a TAL on the 77mm ammo if I can find it.

Leo
 
THIS INFO APPEARS TO BE FROM THE MID 1950S

The 17 Pdr gun was originally designed as an anti-tank weapon and was provided with a H.E. shell for use against targets which would not normally be engaged with shot. The use of the gun was subsequently extended and it may now be met with on field, S.P. and tank mountings. The ammunition is interchangeable in all 17 Pdr equipment except as stated below.

AMMUNITION

(a) Q.F. fixed ammunition (except Paper Shot, which is Q.F. separate) of the following Service types Ad used

Cartridge, Q.F. 17 Pdr. H.E./T. Shell.
Cartridge, Q.F. 17-Pdr. Reduced Charge H.E./T.
Cartridge, Q.F. 17 Pdr. Reduced Charge H.E./H.C/T.
Cartridge, Q.F. 17 Pdr. Reduced Charge H.E./Super H.C./T
Cartridge, Q.F. 17 Pdr. B.E. Screening Smoke
Cartridge, Q.F. 17 Pdr. B.E. Coloured Smoke
Cartridge, Q.F. 17 Pdr. A.P.C./T. Shot
Cartridge, Q.F. 17 Pdr. A.P.C.B.C./T. Shot
Cartridge, Q.F. 17 Pdr. Practice/T.
Cartridge, Q.F. 17 Pdr. Reduced Charge, Practice, Flathead/T
Cartridge, Q.F. 17 Pdr. S.V. A.P.D.S./T. Shot
Cartridge, Q.F. Blank, 17 Pdr
Cartridge, Q.F. Clearing, 17 Pdr
Cartridge, Q.F. 17 Pdr, Drill, A.P.D.S
Cartridge, Q.F. 17 Pdr. for use with Paper Shot.
Cartridge, Shot, Paper, Q.F. 17 Pdr.

(b) As 17 Pdr and 77mm. projectiles are identical, it was decided, in 1944, to amend the designation of all the then current projectiles to include "17 Pdr. and 77mm." in the nomenclature and all current projectiles are designated in this way.

(c) Since the chamber capacity of the 17 Pdr gun is greater than that of the 77mm and the cartridge cases are consequently of different design complete rounds are not interchangeable between the two equipments.
For this reason complete rounds include one equipment only in the nomenclature, i.e., the equipment for which the round, as a whole, is designed.
 
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