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What Happens To Amtraks/amtanks After The Initial Landing Is Made?


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#61 rmgill

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Posted 10 March 2018 - 2304 PM

Yep. I'm pretty sure they were 20mm Polsten guns, normally used for AA use, but obviously better used for ground employment with the absence of the Luftwaffe. 


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#62 DougRichards

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Posted 11 March 2018 - 0013 AM

Yep. I'm pretty sure they were 20mm Polsten guns, normally used for AA use, but obviously better used for ground employment with the absence of the Luftwaffe. 

 

Could have been Oerlikon guns, as they were used more or less interchangeably. 

 

The old Arifix Water Buffalo kit in 1/76, that I first built sometimes in the late 1960s, was the LVT 4 with the 20mm mount.

 

DSC4592.jpg


Edited by DougRichards, 11 March 2018 - 0015 AM.

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#63 Chris Werb

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Posted 11 March 2018 - 0907 AM

According to wiki in Jan 44 21st Army group decided that only polsten 20mm would be issued to simplify logistics.
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#64 Gavin-Phillips

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Posted 11 March 2018 - 1342 PM

Was the 20mm Polsten used instead of the M2 .50cal HMG or in addition to on the LVT-4?      


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#65 Chris Werb

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Posted 13 March 2018 - 1511 PM

Was the 20mm Polsten used instead of the M2 .50cal HMG or in addition to on the LVT-4?      


Instead of. Two .30 M1919A4 with or without shields were typically retained one either side of the payload area.
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#66 Gavin-Phillips

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Posted 14 March 2018 - 1143 AM

 

Was the 20mm Polsten used instead of the M2 .50cal HMG or in addition to on the LVT-4?      


Instead of. Two .30 M1919A4 with or without shields were typically retained one either side of the payload area.

 

Thanks.

 

Since the LVT(A)-1 "amtank" with its 37mm gun-armed turret (modified M3 Stuart tank turret I do believe) was soon replaced by the LVT(A)-4 and LVT(A)-5 with its 75mm short howitzer, I wonder if the single Polsten 20mm would really have offered anything beneficial over the installation of 2 M2 .50cal HMG's?  As far as dealing with shore-based defences, pillboxes and entrenched infantry, would a 20mm be enough to deal with those? 


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#67 DougRichards

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Posted 23 March 2018 - 1630 PM

 

 

Was the 20mm Polsten used instead of the M2 .50cal HMG or in addition to on the LVT-4?      


Instead of. Two .30 M1919A4 with or without shields were typically retained one either side of the payload area.

 

Thanks.

 

Since the LVT(A)-1 "amtank" with its 37mm gun-armed turret (modified M3 Stuart tank turret I do believe) was soon replaced by the LVT(A)-4 and LVT(A)-5 with its 75mm short howitzer, I wonder if the single Polsten 20mm would really have offered anything beneficial over the installation of 2 M2 .50cal HMG's?  As far as dealing with shore-based defences, pillboxes and entrenched infantry, would a 20mm be enough to deal with those? 

 

 

 

Given that the British were using the LVT for river crossings rather than shore assault, it would be considered that land based supporting artillery on the British occupied side of the river would have handled any identified defences. 

 

The 20mm would have been for local AA defence and to bolster the overall HE firepower available. The overall weight of fire of a Polsten (heavier rounds) would have exceeded two .5 cal and fragments generated by the HE, together with the deterrent effects of lots of bangs, rather than quieter 'thuds' would also tend to keep the heads of infantry down.

 

220px-50BMG_size_comparison.JPG


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#68 shep854

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Posted 23 March 2018 - 1916 PM

Also, it seems that .50 love was primarily an American thing.  Other countries seemed happy with rifle-caliber MGs and 20mm for heavier fire.


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#69 rmgill

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Posted 23 March 2018 - 1934 PM

Brits had .55 and .50 Vickers too. 

ARMY_TRAINING_001_013-0.55_inch_Boys_Ant


HMS_Vanity_Vickers_.50_guns_1940_IWM_A_1

They just upgraded to 15mm BESA and 20mm Polsteen to get better firepower. 

IWM-H-17835-Humber-Armoured-Car.jpg


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#70 Colin

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Posted 23 March 2018 - 1942 PM

The Vickers .5 was defiantly not the .50cal BMG


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#71 Chris Werb

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Posted 23 March 2018 - 2016 PM

The Vickers .5 was defiantly not the .50cal BMG

 

And the quad Vickers was replaced by a single Oerlikon 20mm and, where weight permitted, later a twin 20mm or single 40mm. They were phased out comparatively quickly once Oerlikon production got into full swing in the States.


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#72 shep854

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Posted 23 March 2018 - 2301 PM

But only the Yanks placed .50s on every vehicle they possibly could...
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#73 Chris Werb

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Posted 24 March 2018 - 1050 AM

But only the Yanks placed .50s on every vehicle they possibly could...

 

The problem with the .50 vs the 20mm is that, as Ken often pointed out, it has an ECR of a few mm more than a rifle calibre MG, whereas a cannon or AGL firing fragmentation rounds has a vastly larger ECR. It can damage aircraft much more than a rifle calibre MG, but against that, the M2HB used in vehicle mountings has a pretty lousy RoF (550 rpm?) optimised for ground targets and I would not want to try hitting an aircraft with one from a typical vehicle mount. The UK, for example, went for .30s on tanks where they had commander's MGs even though .50s could have been provided.


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#74 Colin

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Posted 24 March 2018 - 1214 PM

The .50cal is a good reliable weapon still very much in service today, hell it's the only "heavy" armament on our MCDV class vessels. Canada almost ditched all of ours, now we are bringing them back. They fill a niche for a heavier round when a 20mm is to big such as in smaller vehicles and they are cheaper to produce. 


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#75 DogDodger

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Posted 24 March 2018 - 1458 PM

The problem with the .50 vs the 20mm is that, as Ken often pointed out, it has an ECR of a few mm more than a rifle calibre MG, whereas a cannon or AGL firing fragmentation rounds has a vastly larger ECR. It can damage aircraft much more than a rifle calibre MG, but against that, the M2HB used in vehicle mountings has a pretty lousy RoF (550 rpm?) optimised for ground targets and I would not want to try hitting an aircraft with one from a typical vehicle mount. The UK, for example, went for .30s on tanks where they had commander's MGs even though .50s could have been provided.

The US Army vacillated on this topic. In September 1942, the Ordnance Committee stipulated that .30 cal MGs replace the .50 cal MG on tanks, but the troops objected and the decision was reversed in April 1943. By February 1949, the Army Field Forces Advisory Panel on Armor said of the TC's MG: "The ground use of this weapon is of primary importance. The antiaircraft role is of secondary importance."
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#76 DougRichards

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Posted 25 March 2018 - 0303 AM

The .50cal is a good reliable weapon still very much in service today, hell it's the only "heavy" armament on our MCDV class vessels. Canada almost ditched all of ours, now we are bringing them back. They fill a niche for a heavier round when a 20mm is to big such as in smaller vehicles and they are cheaper to produce. 

 

Browning .50 MG1945 $1560   (https://www.warhisto...ing-wwii.html/3)

 

 

 

Polsten  £60 and £70  =  US$350 in 1945


Edited by DougRichards, 25 March 2018 - 0542 AM.

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#77 R011

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Posted 25 March 2018 - 1153 AM

Actually, the five-oh was free thanks to Lend Lease and only $156.00 if the UK decided to keep it.

I would suspect, though, that the reason for replacing it was there was a lot of 20 mm ammo in the system as it was there for AA use while .50 was not much used even if they had a fair number of BMG.

Edited by R011, 25 March 2018 - 1154 AM.

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