Monday, 2 October 2017

Lend Lease Impressions: 57 mm M1 Anti-tank Gun

"57 mm M1 Anti-tank Gun

American 57 mm M1 Anti-tank Gun

The gun has a semiautomatic vertical sliding breech, the semiautomatic mechanism is a mechanical type. The mount has split trails. The gun fires one-piece armour piercing shot (without explosive filler).

The following is a comparison of main characteristics of the American 57 mm anti-tank gun and our 45 mm anti-tank gun mod. 1942, 57 mm IS-1 anti-tank gun, and 76 mm ZIS-3 gun.

Characteristics
45 mm anti-tank gun mod. 1942
American 57 mm M1 gun
57 mm IS-1 anti-tank gun
76 mm ZIS-3 divisional gun
Mass in battle position, kg
570
1140
1120
1120
Shell mass, kg
1.43
2.85
3.14
6.5
Muzzle velocity, m/s
870
815
900
655
Penetration of a K-2400 armour plate at 90 degrees




100 meters
70 mm
78 mm
98 mm
75 mm
300 meters
65 mm
70 mm
91 mm
72 mm
500 meters
61 mm
63 mm
86 mm
69 mm
1000 meters
51 mm
48 mm
71 mm
61 mm

The American 57 mm anti-tank gun weighs about as much as our 57 mm IS-1 anti-tank gun, but the penetration is significantly less than that of our gun, and is only somewhat higher than that of the 45 mm anti-tank gun mod. 1942, which weighs almost half as much as the American gun.

As a result of trials performed with this gun, it was established that the main drawback is the dependence of the recoil mechanisms on the temperature of the hydraulic fluid (in winter conditions). Until the fluid is heated, the gun will not return to its original position after recoil.

The gun has insufficient clearance, the diameter of the wheels is too small, and the suspension is rigid, which lowers the qualities of the gun on maneuver, especially when pushing it across the battlefield with the force of the crew. 

The design of the gun does not satisfy modern requirements for anti-tank guns, and makes it suitable for stationary defenses only.

57 mm armour piercing tracer shot

Ammunition for the 57 mm M1 anti-tank gun

57 mm armour piercing tracer shot, American make
The results of trials were satisfactory. The shot is a modern design, but it is inferior to domestic 57 mm armour piercing shells due to the higher muzzle velocity of the latter.

20 comments:

  1. Some US units equipped with these guns in 1944-45 started essentially abandoning them and using bazookas instead. Obviously the bazooka was much worse in many ways, but it was highly portable and more versatile.

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  2. Amazing how good the 76mm ZIS-3 was really....about the same weight, and performance as the British/US 57mm in the AT role, but, it fired a very useful HE round also so it was much more useful as a general purpose gun.

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  3. Wait, the AP Shot M70, that has the same weight as the round tested here, almost the same speed (853m/s instead of the listed 815m/s) has a LOT more penetration when it was tested by the 'western' allies themselfs... So my question is what ammo did they get? or what went wrong in testing?

    Since the American gun should compare to the russian 57 and the british QF 6-pounder (That is nearly identical to the american one, barrel length of the American was better until the Brits started using the Mark IV gun) was in service till 1951 with the army, and it was even used in the Korean war...

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    Replies
    1. Different testing standards. Soviet penetration figures are lower for all foreign guns, across the board.

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    2. The British repeatedly upgraded the 6pdr's ammunition. By March 1944, APDS rounds were in service. The US didn't manufacture anything beyond the base AP nature and sometimes omitted the charge from even that. Units in the field obtained the good stuff whenever they could. I wonder which natures the USSR tried?

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  4. The Soviet 57mm had a MUCH longer gun tube than the US/British 57mm. I don't know the ammo details but I would think the Soviet gun would have far better performance.

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    Replies
    1. The IS-1, the gun in this table, had a shortened barrel.

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    2. I am not familair with the IS-1 57mm....I assume the performance of the ZIS-2 57mm is much better though.

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    3. The Canadians made a souped up 6 pdr in 43, the "Canuck" a much longer barreled higher velocity version. Sadly while finished it was just kept in testing until after the war, The Canadians only wanted to adopt it if the British did and they were unsure/dragging their feet over it the entire time.

      APCBC 3.23 kg fired at about 950-1005 m/s
      Canadian CR 1.93 kg fired at about 1250 m/s

      APCBC https://i.imgur.com/il5JTfU.jpg
      CR https://i.imgur.com/3WUnkfZ.jpg

      Sabot could be fired as well but I don't really have much data on that.


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    4. There was also the 6-pdr David, firing 2-pdr projectiles as the subcaliber penetrator. Suffered the same fate, unfortunately.

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    5. Yea :/

      Back before the 17 pdr was placed in the Sherman the UK did request all data on the Canuck as a possible alternative to mount instead of the 17 pdr. In the end it hinged on the British wanting to know the performance of the APCBC round compared to the 17 pdr, it was also stated as they did not have enough supply of tungsten to provide enough rounds for all weapons so APCR performance was less interesting to them. Canada responded that they had in excess of 2,000,000 lbs in stock at the time...

      The original requirements for the gun are interesting as well, "requirement for this project is to defeat the 100mm spaced plate armour of the PzKw VI tank attacked at 30 deg to normal at ranges 800 to 1000 yards"

      I guess during this period they were expecting Tigers to appear with spaced design like on the III and IV.

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  5. Penetration of british 57mm and soviet 57mm guns was the same in practice, as demonstrated by the attempts to defeat TIGER side armor.
    This was despite the shorter barrel of the british 57mm. Cause of the soviet´s 57mm problem was their inferior AP ammunition.

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    Replies
    1. I posted tests of Soviet ZIS-2 and British 6-pounder against a captured Tiger. The ZIS-2 performs better. ZIS-2 penetrates the side every time from 1000 meters, the 6-pounder only penetrated with one shot in three. I don't know how you established that Soviet AP was worse from this.

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    2. Every time? I count one out of four penetrations for 57 ZIS-2 at 1000m. Three hits were not penetrating. according to this picture from the soviet test:

      http://warspot.ru/9797-tyazhyolyy-trofey/images?name=%2F000%2F044%2F676%2Fcontent%2Ftigerussr10-508d472b445925882819ba5017237f2a.jpg


      http://warspot.ru/9797-tyazhyolyy-trofey

      I quote
      "Следующими по немецкому танку открыли огонь орудия калибра 57 мм. И советская противотанковая пушка ЗИС-2, и английская 6-фунтовая противотанковая пушка показали похожие результаты. Борт «Тигра» пробивался на дистанции 800–1000 метров. Что же касается стрельбы в лобовую часть танка, то ЗИС-2 не смогла ее пробить на дистанции 500 метров. На более близких расстояниях обстрел проводить не стали, но в целом на дистанциях около 300 метров немецкий тяжелый танк, вероятно, ею уже поражался, о чём говорят данные, полученные от англичан. Стоит отметить, что английская противотанковая пушка имела меньшую длину ствола. Схожие с советской пушкой характеристики пробития обеспечивались благодаря более качественным снарядам."

      So actually yes, the russian source confirms that soviet AP ammunition was worse, not surprising. 6pdr and ZIS-2 were equal in penetration, despite the latter having much more muzzle energy.

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    3. "Similar" and "equal" are different words in both the Russian and English language.

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    4. Pasholok (the very same Pasholok whose writings you keep dismissing as propaganda, by the way) writes that the ZIS-2 probably would have penetrated the front from 300 m. The British didn't bother shooting at the front of the Tiger with APCBC, but shots at the side at 30 degrees (95 mm equivalent, give or take) fail to penetrate.

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    5. "the ZIS-2 probably would have penetrated the front from 300 m. The British didn't bother shooting at the front of the Tiger with APCBC, but shots at the side at 30 degrees (95 mm equivalent, give or take) fail to penetrate. "

      Extremely questionable and highly unlikely in my opinion. In order to be true, this statement presumes a projectile quality which the soviets only obtained in the early 50´s, that is a steel AP, which neither deforms nor breaks up when striking at elevated velocities.
      The actual 57mm projectiles manufactured during ww2 did not stay intact striking at velocities of even 800´ish m/s and quite likely would fall victim to a more severe, complete form of shatter induced by too high impact velocities at 100-300m range. Compared to the british 6pdr APCBC-shot the soviet domestic 57mm BP-271 had too large HE cavity, too low nose hardness, too low impact toughness at base, and a lack of armor piercing cap.
      Considering the problems, the british already experienced with their uncapped 6pdr AP-shot (necessating the development of 6pdr APCBC), it is reasonable to assume that shatter would be the normal failure mode of the BP-271 striking any discriminate target (>1.25 plate/cal).

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  6. Ah, so Pasholok's findings just happen the become false when they are inconvenient to you. Wonderful how quickly your opinion on his appraisal of the trials flips.

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  7. He is entitled to have his own opinion and in my view correctly assessed the superior 17pdr ammunition quality based upon available evidence from the tests he cited based upon the criterium that penetration was equal despite the considerably lower muzzle energy of the 17pdr. The 2nd part, however is not based upon any evidence and thus cannot be regarded as his findings but his speculation.

    -Actually, You can look at the picture he published, it will show the remains of a 57mm BP-271 resting on top of the armor with broken off nose (several failed to penetrate 82mm @1000m and 0° already). The distance was 1000m and the armor only 80mm (1.4cal/plate).
    You can figure out what happens if the penetration condition changes to 1.75cal/plate and the impact velocity goes up to 300m range. The projectile break up doesn´t disappear miracolously when the kinetic stress exposure is considerably increased.

    In light of the problems the higher quality US ammo had with shatter at close range against these sorts of targets, it remains an interesting question whether or not shatter effects make the 80mm armor immune again at very close range with such a poor quality AP.

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  8. "several failed to penetrate 82mm @1000m and 0° already"

    The actual trials document shows only one failure to penetrate by the ZIS-2 from 1000 meters, but sure, the great critical mass knows more about the trials than the people who performed them, as always.

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