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U.S. Army Firing Test of 76mm & 17pdr

Discussion in 'Weapons & Technology in WWII' started by acker, Jun 9, 2009.

  1. acker

    acker Member

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    This webpage has been copied from the following site: U.S. Army Firing Test of 76mm & 17pdr - World War II Zone Forums

    I'll highlight the beginning and end of this document.


    U.S. Army Firing Test No.3
    U.S. Army Firing Tests conducted August 1944 by 12th U.S. Army Group at Isigny, France.
    Board of Officers
    APO 655


    30 August 1944

    SUBJECT: Final report of board of officers appointed to determine comparative effectiveness of ammunition of 76mm gun and 17pdr gun.

    TO: Commanding General, Twelfth Army Group.

    1. The board convened pursuant to the attached order at the firing range established by First U.S. Army near Isigny, France at 1030 hours, 19 August 1944 and conducted firing tests against the front plate of German Panther Tanks. The firing was continued, as the weather and the availability of target tanks permitted, on 20 and 21 August 1944. Because of the urgency of the test, a preliminary report, dated 21 August 1944, was submitted on 22 August 1944.

    2. Ammunition
    a. The characteristics of the standard ammunitions tested are shown below:

    Ammunition M/V Complete
    Rd. Wt. Projectile
    Weight Description
    76mm APC M62
    (Lot# ODCM-104) 2600 24.80 15.44 Armor piercing cap, windshield, base fuze, and tracer.
    76mm HVAP T4
    (Lot# PA 9-1) 3400 18.90 9.50 Light weight projectile with 3.9 lb tungsten carbide core 1½" in diamter in steel sheath. Aluminium body, steel base, windshield, and tracer.
    17pdr APCBC
    (Lot# JIB 3/44-2301) 2900 35.50 17.00 Armor piercing cap, windshield, and tracer.
    17pdr SABOT
    (Lot# KBY 7/44-Lot 2) 3950 26.30 08.15 Discarding SABOT with 3.9 lb tungsten carbide core 1½" in diameter, steel base, and tracer.

    b. In addition to the above ammunitions, the board fired 76mm HVAP projectile from a 17pdr anti-tank gun, with 17pdr APCBC and 17pdr SABOT propelling charges in a 17pdr APCBC cartridge case.

    3. Nature of Test
    a. The above ammunitions were fired at the front plate of three Panther tanks. The general characteristics of the frontal armour are: Glacis Plate 85mm (3.35") at 55º and Nose Plate 65mm (2.56") at 55º. using U.S. armor basis curve, the verticle equivalent of the glacis plate is 187mm (7.36") and of the nose plate 139mm (5.47"). Due to the inclination of the ground, the angle with the verticle of the glacis plates on the tanks used in this test were: 57º 34', 57º 05', and 56º 53'. The nose plate on one of the tanks tested measured 66.67mm (25/8").

    b. Wide variation was found in the quality of glacis plate on the three tanks. Tank No.2 (hereafter referred to as the "best plate") sustained 30 hits as ranges from 600 to 200 yards without cracking. Tanks Nos.1 and 3 (hereafter referred to as "average plate") cracked after relatively few hits. All conclusions are, therefore, based solely on the relative performance of rounds fired at a single plate. Comparisons are not made between rounds fired at different plates. Also, the performance of any ammunition in this test cannot be considered a criterion as to the range at which it will penetrate the front plate of a Panther tank... [last few words of sentence are illegible].

    c. Effectiveness was determined by balancing penetrations against the number of rounds fired and the number of hits obtained on the specific plate.

    d. A penetration was defined as occuring only when the projectile passed completely through the plate. Only fair hits were considered in determining penetrations. Rounds striking edges of the plate, welds and junctions of the plate, and cracks in the plate were not fair hits.

    e. The line of fire was approximately perpendicular to the lateral axis of the target tanks.

    f. The 17pdr guns were fired by two superior British enlisted gunners. The 76mm gun was fired by two officers with considerable test firing experience.

    4. Results of Test
    a. A tabulation of the detailed results, with photographs, is attached as Appendix A1.

    b. Accuracy

    (1) A tabulation does not present a true picture of the comparative accuracy of the various ammunitions. With all the standard rounds, except 17pdr SABOT, the accuracy was such as to warrant attempting to hit specific parts of the front plates. In general this was successful, but some rounds fired at the lower glacis struck the upper nose, and vice versa. In addition, it was not possible to position all the tanks so that the nose was not, at least partially, hidden by the ground line. Therefore, it is felt that a better measure of accuracy can be obtained by considering the nose and glacis as one target.

    (2) On this basis all twenty-two (22) rounds of 76mm HVAP, T4, and all twenty-three (23) rounds of 17pdr APCBC hit the target. Only one (1) of eight (8) rounds of 76mm APC, M62, which fell short attempting to hit the nose, failed to hit the target. Forty-two (42) rounds of 17pdr SABOT were fired and only 57% [24 rounds] were hits. More rounds of 76mm APC, M62 were not fired since its accuracy had been well established in previous firing in the U.S. by two members of the board.

    (3) Insufficient firing was conducted with 76mm HVAP projectile with 17pdr APCBC and 17pdr SABOT propellant to determine definite sight settings for a conclusive accuracy test. The results of the limited firing indicated that these rounds are of an accuracy comparable with 76mm HVAP and 17pdr APCBC.

    c. Penetration

    (1) At 600 yards, 17pdr APCBC penetrated the lower nose of tank No.1 (average plate), while 76mm HVAP failed to penetrate.

    (2) At 400 yards, one round out of four fair hits of 17pdr SABOT penetrated the glacis of tank No.2 (best plate). This was the only penetration of this plate by a fair hit with any of the ammunitions (including 76mm HVAP w/17pdr APBC propellant, 76mm HVAP w/17pdr SABOT propellant) at ranges 200 yards and over.

    (3) At 400 yards, one round out of one fair hit with 17pdr APCBC and one round out of one hit with 17pdr SABOT penetrated the lower nose of tank No.2 (best plate). Both rounds of 76mm APC, M62 failed to penetrate, and one round of 76mm HVAP penetrated while the second round failed to penetrate. Two rounds out of two hits of 76mm HVAP w/17pdr SABOT propellant also penetrated.

    (4) At 200 yards one fair hit with each of the standard ammunitions failed to penetrate the glacis of tank No.2 (best plate). The relative depths of the partial penetrations at this range were as follows:
    (a) 17pdr APCBC - 2"
    (b) 17pdr SABOT - 1 7/8"
    (c) 76mm HVAP - 1 5/16"
    (d) 76mm APC, M62 - 1"

    (5) At 200 yards firing at the glacis of tank No.3 (average plate) one round out of four fair hits with 76mm HVAP penetrated, this round, after partially penetrating, ...[illegible word]... and penetrated the plate ...[illegible word]... . One round of 17pdr SABOT penetrated and one round failed to penetrate at this range. One fair hit with 17pdr APCBC failed to penetrate, but cracked the plate. The second round striking within 6" of the first round penetrated.

    (6) In contrast to the results obtained in this teast with 17pdr SABOT, in firing conducted by First U.S. Army at Balleroy on 10 July 44, 5 rounds were fired at the front plate of a Panther tank at 700 yards. Examination of pictures of this firing indicates that the first round struck the mantlet, the second between the track and the nose plate, the third at the junction of the nose and glacis and penetrated. The fourth and fifth were fair hits on the glacis and both penetrated. The conflict between these results and those obtained by the board is expalined by Col. A. G. Cole, Deputy Director of Artillery, Ministry of Supply. Col. Cole witnessed part of the test and states that the ammunition lot furnished the board had not been proof fired. He further states that, in his opinion, the lot is of sub-standard manufacture and if proof fired would not have been accepted.

    (7) 76mm APC, M62 fair hits which failed to penetrate caused no cracking of the plate of average quality. 76mm HVAP, 17pdr SABOT, and 17pdr APCBC caused cracking in varying degrees. In general, 17pdr APCBC caused greater damage to the plate than 17pdr SABOT or 76mm HVAP.

    5. Findings
    a. The 17pdr SABOT fired in this test has penetrating power equal or slightly better than that of the 17pdr APCBC and the 76mm HVAP, T4. It is, however, definitely inferior to these ammunitions because of its inaccuracy. The board invites attention to the fact that its findings and conclusions apply only to the ammunition furnished it and may not apply to good quality 17pdr SABOT.

    b. The accuracy of 76mm APC, M62 is satisfactory. However this ammunition is definitely inferior to either the 17pdr APCBC or the 76mm HVAP, T4, because of its poor penetrating power.

    c. The 17pdr APCBC and the 76mm HVAP, T4, are both highly accurate ammunitions. In the opinion of the members of the board, two of whom have had considerable experience test firing British and American tank and antitank weapons, the 76mm HVAP, T4 is the most accurate tank or antitank ammunition encountered to date.

    d. The 17pdr APCBC is more effective against the front of a Panther tank than is the 76mm HVAP, T4. Its margin of superiority is not great. Neither one can be depended upon to penetrate the glacis plate in one fair hit on average quality plate.

    e. Combining 76mm HVAP, T4 projectile with 17pdr APCBC propellant offers no advantages over a standard ammunition.

    f. Because of its accuracy and since the core is essentially the same as that in 17pdr SABOT, 76mm HVAP, T4 projectile with 17pdr SABOT propellant may provide an ammunition superior to 17pdr SABOT as regards accuracy and to 17pdr APCBC and 76mm HVAP as regards penetration.

    6. Conclusions
    a. That the 17pdr SABOT of the lot tested is considered an unsatisfactory ammunition because of its inaccuracy.

    b. That the 76mm APC, M62 is considered an unsatisfactory ammunition for use against heavy armor because of its inferior penetration.

    c. That the 17pdr APCBC and the 76mm HVAP, T4 are considered the best antitank ammunitions available in these calibers for use against heavy armor. The 17pdr APCBC is somewhat superior to the 76mm HVAP, T4, against the Panther Tank. Neither one can be be depended upon to penetrate the glacis plate of the Panther in one fair hit on average quality plate.

    d. That the possibilities should be investigated of using 76mm HVAP, T4 projectile with 17pdr SABOT propellant, if 17pdr guns are made available to U.S. units.

    Andrew P. O'Meara, Colonel, F.A., President.
    Francis B. Shearer, Colonel, Ord, Member.
    John B. Routh, Lt Col, F.A., Recorder.

    3 Incls.
    Incl No.1 - Appendix "A".
    Incl No.2 - Photographs of firing. Numbers 1-27 inclusive1.
    Incl No.3 - Letter order, HQ 12th Army Group (Rear), dated 16 August 1944, Subject: "Appointment of Board of Officers".




    Am I missing something here, or was the US and British HVAP ammunition really this terrible? This goes against pretty much every Gun/Armor Table I've seen on the Internet. Why in the world were the results thus?

    I think I'm missing something, but I'm not sure what.
     
    Slipdigit likes this.
  2. Triple C

    Triple C Ace

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    Terrible? Actually, I can think of no Allied weapon except the 17 pdr. APDS & 90-mm. HVAP that was capable of penetrating Panther's thick and ridiculously sloped glacis armor. The 17 pdr. and 76-mm. HVAP rounds could however knock out a Panther frontally with mantlet hits.
     
  3. acker

    acker Member

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    I see. But I'm still confused as to the armor tables posted on the Internet. So far as I can tell, the 76mm HVAP could penetrate around 130mm at 900 yards. But that performance doesn't seem to match the tests shown above...I would have expected at least 1 penetration from the 76mm HVAP at 500 meters or so.

    I suppose a more accurate indicator of theoretical vs. actual testing could be done if there were more documents of a similar nature.
     

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