ShVAK vs. MG 151/20

[Finkeren]

largest advantage wa sthe ammunition as you posted and the operational advantages that you cited as small. Production, duirability etc.. those are HUGELY important isn a long campaign and are the difference between the gun being there to fire .. and not being there.

 

That is main reason US used those .50. Easy to produce, already mass produced and reliable. That does not win a combat, but wins a war.

I can see your point, and I somewhat agree, but there are two important points we are ignoring:

 

1. Regardless of its higher production costs, the USSR were still able to produce enough ShVAKs to fill the need. I may be ignorant about this, but I have never read about any significant shortage of ShVAKs. The slower/more expensive production doesn't seem to have had much influence in this case.

 

2. The complicated mechanism made of softer steel gave the ShKAS/ShVAK a shorter service life yes, but compared to the service life of an aircraft engine, it's really a minor issue. The loss rates sustained by the VVS makes service life even less important. During most of the war, it was rare for a Soviet combat aircraft to endure 50 missions without being either destroyed, written off or undergo a complete overhaul. Even if a Yak pilot emptied his ammunition completely on every single mission, something not even close to reality, his ShVAK would still only have fired a total of 6000 rounds during those 50 missions. Even if we take into account the guns scavenged from write-offs and stalled in new aircraft, only a very small minority of aircraft mounted ShVAKs would ever have reached the end of their service lives.

[Gunsmith86]

2. The complicated mechanism made of softer steel gave the ShKAS/ShVAK a shorter service life yes, but compared to the service life of an aircraft engine, it's really a minor issue. The loss rates sustained by the VVS makes service life even less important. During most of the war, it was rare for a Soviet combat aircraft to endure 50 missions without being either destroyed, written off or undergo a complete overhaul. Even if a Yak pilot emptied his ammunition completely on every single mission, something not even close to reality, his ShVAK would still only have fired a total of 6000 rounds during those 50 missions. Even if we take into account the guns scavenged from write-offs and stalled in new aircraft, only a very small minority of aircraft mounted ShVAKs would ever have reached the end of their service lives.

 

The lifetime of a ShVAK barrel was only 2000-3000 rounds!

Later in the war it was improved to about 4000-5000 rounds (1944-1945)

[Finkeren]

The lifetime of a ShVAK barrel was only 2000-3000 rounds!

Later in the war it was improved to about 4000-5000 rounds (1944-1945)

A barrel change isn't a big deal, but breakdown of the cycling mechanism is. Still, even 3000 rounds corresponds to A LOT of missions, propably more than was the average life expectancy of a VVS fighter in 1942/43.

[AX2]

The ShVAK it was a formidable weapon, a little above the MGs 

Also the MG 15 and the MG 150/20 did a good job against any planes

 

I have some data on the effectiveness of the MG 15 and MG 151/20 against the IL2 the flying tank.

 

 

 

При специальных испытаниях на обстрел бронекорпусов одноместных Ил-2 из немецкого крупнокалиберного пулемета MG-151/15 калибра 15 мм, проведенных на заводе № 125 в июле-августе 1942 г., было установлено, что: задняя бронеплита из цементированной брони марки ХД толщиной 12 мм не обеспечивает защиты от бронебойных пуль калибра 15 мм при обстреле с дистанции 400 м и ближе в конусе до 40° от продольной оси самолета; боковые бронеплиты из гомогенной брони марки АБ-1 толщиной 6 мм не обеспечивают защиту от бронебойных пуль этого калибра с дистанций менее 400 м под углом к продольной оси самолета свыше 20°; при попадании фугасных пуль этого же калибра с дистанции 100 м и выше под углами не более 30° к продольной оси самолета задняя и боковые бронеплиты не поражались.

Для выведения Ил-2 из строя необходимо было обеспечить более 7 попаданий 20-мм фугасных снарядов в фюзеляж (размеры пробоин в обшивке фюзеляжа колебались в пределах 120-130 мм). Однако вероятность перебития осколками снарядов тросов управления рулем поворота штурмовика в этом случае была очень велика.

Статистика боевых поражений Ил-2 показывает, что на долю системы управления (рули, элероны и проводка управления ими) приходилось 22,6% всех поражений. В 57% случаев попадания снарядов в фюзеляж Ил-2 происходило перебитие тросов управления рулем поворота и 7% попаданий приводили к частичному повреждению трубчатых тяг рулей высоты.

Попадания 2-3-х фугасных снарядов немецких авиапушек калибра 20 мм в киль, стабилизатор, руль поворота или высоты было вполне достаточно для вывода Ил-2 из строя...

 

 

 

( Google translator  )

 

For special tests to the firing of single hulls IL-2 of the German heavy machine gun MG-151/15 caliber 15 mm, held at the factory number 125 in the July-August 1942, it was found that: the rear armored plate of hardened armor thickness of 12 brands of CD mm, no protection against armor piercing bullets caliber of 15 mm during the shelling of the 400 meters and closer to a cone up to 40 ° from the longitudinal axis of the plane of the side armor plates of homogeneous armor brand AB-1, 6 mm thick do not provide protection against armor piercing bullets of this caliber from distances less than 400 m at an angle to the longitudinal axis of the airplane above 20 °; in contact with explosive bullets of the same caliber with a distance of 100 m and above at angles of 30 ° to the longitudinal axis of the airplane back and side armor plates are not amazed.

For the estimation of IL-2 shot down was necessary to provide more than 7 hits 20-mm high-explosive shells into the fuselage (size holes in the fuselage skin ranged between 120-130 mm). However, the probability of broken shell fragments rudder control cables stormtrooper in this case was very high.

 

Statistics military defeats IL-2 shows that the share of the control system (rudder, ailerons and wiring management) accounted for 22.6% of all lesions.

 In 57% of cases falling into the fuselage shells IL-2 occurred broken rudder control cables and 7% hit resulted in partial damage to the tubular rod elevators.

Hit 2-3-explosive shells German aviapushek caliber 20 mm fin stabilizer, rudder or height was enough to bring the IL-2 down ... 

 

Edited September 1, 2013 by Mustang

[VeryOldMan]

Well a 15mm cannon  is far far weaker than a 20mm one. The  volume of explosive is  way different.   If the projectile has same lenght it would have 1.8 times more  mass.  The  text gets a bit confusing since most of  it talks about MG-151/15 and  then has a single 20mm  quote...  strange. Feels like somethign was lost there

[Finkeren]

Well a 15mm cannon is far far weaker than a 20mm one. The volume of explosive is way different. If the projectile has same lenght it would have 1.8 times more mass.

Somewhat true, but you're dicounting the far superior penetrating power of the 15mm, which could penetrate at least most of the rear facing armour on the IL2.

[AX2]

Somewhat true, but you're dicounting the far superior penetrating power of the 15mm, which could penetrate at least most of the rear facing armour on the IL2.

Also the MG 151/20 mm can enter into the IL2  fuselage or cockpit, like going into a butter armor

 

Hit and Clip the wings of an IL2, in think not! , But.. you maybe get wings ammuniton explosion

Hit the fuselage with 15 mm or 20mm  HE ammunition,

And you will break  tail´s  controls and/or elavators controls  and/or trim controls.

The advantage of explosive ammunition is break controls rods, Bend bars and/or cut the wire controls.

Destroy or break the oil cooler or the oil tank, break the water radiator or water lines of the engine.

Or Make a BIG hole in the fuel tank..  and start fire.

Something like... go through the armor and the dynamite explodes inside, simple but realistic..

 

 

 

 

 

 

 

 

 

 

Edited September 3, 2013 by Mustang

[JG1_Pragr]

I think that the ammunition was the biggest issue derogated the ShVAK. The gun itself was probably the best 20mm canon of the war (in serial production) but still the armament effectiveness is always considered as overall performance of gun and ammunition it uses.

 

The projectile weight of 20x99 round (ShVAK) was almost 20% less than of 20x82 used in MG 151/20. It use higher amount of explosives (6g vs 3,6g) but what I've read the explosives was weaker than PETN used in German ammo (I'm not 100% sure, it's long time I found any information about the Russian explosives used in aerial ammo).

The projectile weighted as much as 20x82 M-Geschoss, which on the other hand carried 20g of explosives.

 

Another thing needs to be considered is the cartridge. How many rounds of each type is typically used. What I know the common practice Luftwaffe used (except against heavy bombers) was mix of 2M-Geschoss, 2HEI and 1API for every 5 rounds. I have no idea about the mix used by VVS SSSR but even if they used all HE rounds the amount of explosives would be about half of the German cartridge (in case of the same strength of both explosives).

 

Maybe this is the reason why the MG151/20 is considered as stronger armament, even if the ShVAK was probably slightly better construction.

Edited September 3, 2013 by II./JG1_Pragr

[AX2]

The projectile weight of 20x99 round (ShVAK) was almost 20% less than of 20x82 used in MG 151/20. It use higher amount of explosives (6g vs 3,6g) b

 

That's not  is accurate, There are many  ammunition types 

 

MG 151/20 ammunition 

Minengeschosspatrone 151 ohne L'Spur - Nose fuze, no tracer  18.6 g HE 

Proyectile Weight 95g Muzzle Velocity  805 m/s

 

???

[JtD]

He mentioned the M-Geschoss in his next sentence, didn't he?

[AX2]

Yes 

I need take off my sunglasses. 

Edited September 3, 2013 by Mustang

[Crump]

http://www.quarry.nildram.co.uk/WW2guneffect.htm

 

Here is the article those tables reference.  I think those tables come from an earlier draft of the article before Anthony Williams factored in the chemical energy of the ammunition.  They seem to just show kinetic energy without accounting for the cannon shells containing significant amounts of chemical explosive.

[Crump]

 

The lifetime of a ShVAK barrel was only 2000-3000 rounds!

Later in the war it was improved to about 4000-5000 rounds (1944-1945)

 

 

That is not unusual at all.  That also assumes the guns is operated IAW with its firing limitations for a sustained ROF.  Exceeding that greatly reduces the guns life.

 

Here is a table for the P51 firing time limits.  It does not take much abuse to destroy a barrel.  1500 rounds and an M2 .50cal was replaced.

 

It would greatly increase realism if players had to adhere to the limits of their weaponry.

 

 

[VeryOldMan]

That is not unusual at all.  That also assumes the guns is operated IAW with its firing limitations for a sustained ROF.  Exceeding that greatly reduces the guns life.

 

Here is a table for the P51 firing time limits.  It does not take much abuse to destroy a barrel.  1500 rounds and an M2 .50cal was replaced.

 

It would greatly increase realism if players had to adhere to the limits of their weaponry.

 

 

OMG this is a HORRIBLE performance in fact. Woudl be nice to get  the equivalent german specifications, would  put some light over the famous reliability of german  weapons.  IF the  burst firing   capabilities of guns were that bad,  a  pilot woudl prefer a LOT a weapon with slighlty worse ballistics but  far easier to handle cooling ...

[MiloMorai]

As if the pilots worried about destroying the barrels of their guns if it resulted in a 'kill'.

[Crump]

 

OMG this is a HORRIBLE performance in fact.

 

VeryOldMan,

 

If the topic was hunting rifles, I would agree.  However, we are talking large caliber machine guns.  Step your barrel life expectations down tenfold.  Heat is what kills barrels.  Machine guns build up heat extremely fast.  A brand new barrel will not make it to 1000 rounds if the weapon is mistreated thru improper operation.  By that, I mean the operator holds the trigger down and does not observe the firing limitations.

 

The larger the caliber, the faster the ROF, the shorter the barrel life.

 

 

As if the pilots worried about destroying the barrels of their guns if it resulted in a 'kill'.

 

 

Well actually Milo, they did.  Why?  They were real fighter pilots working with real weapons and not playing a game or exercising their imagination.

 

If they broke their weapons, then they became what is termed "defenseless". 

 

While I am sure there where those who were in over their heads and unable to control themselves or their excitement at the moment of the kill, to characterize it as the norm is a slap in the face to the majority of pilots who trained hard and did exactly as they were trained to do during World War II.

[Crump]

 

IF the  burst firing   capabilities of guns were that bad

 

You know that is the instructions for the M2 MG-AW.  It is Operator's Manual.

 

There is no "IF" to it, that is how they were trained to operate the weapon and the engineering limits of the design.

[MiloMorai]

Be sure Crupp that Blakeslee waited the appropriate time (30 seconds) between firing his guns.

 

http://www.spitfireperformance.com/mustang/combat-reports/4-blakeslee-22april44.jpg

 

Or how about Godfrey

 

http://www.spitfireperformance.com/mustang/combat-reports/4-godfrey-29march44.jpg

 

a 1 sec burst fires 13 rds @ 800rpm.

[Crump]

 

Be sure Crupp that Blakeslee waited the appropriate time (30 seconds) between firing his guns.

 

 

What are you talking about?  There is nothing in either account that leads anyone to believe the guns were not operated correctly. 

 

If you want Milo, I can go thru each account burst by burst and show you how to read the chart.  The issue is not Blakeslee or Godfrey understanding of how their weapons work, it is your understanding of how it worked.

 

Just PM me as I don't want to derail the discussion and you are the only one with issue with what the Operating Instructions for the weapon depict.

Edited September 27, 2013 by Crump

[MiloMorai]

PM you Crump so you then cry to the mods telling lies about what was said, no way.

[JG1_Pragr]

http://www.quarry.nildram.co.uk/WW2guneffect.htm

 

Here is the article those tables reference.  I think those tables come from an earlier draft of the article before Anthony Williams factored in the chemical energy of the ammunition.  They seem to just show kinetic energy without accounting for the cannon shells containing significant amounts of chemical explosive.

You're wrong. The table contains data for chemical energy. Otherwise 20x82 Minen round wouldn't has more than double of destructive power as API. API and HET are counted as comparable. Both have almost the same volume either incendiary or high explosive components. Because of this they are about the same in terms of destructive power.

Edited September 27, 2013 by II./JG1_Pragr

[Crump]

 

You're wrong.

 

The Q and M values from this article:

 

http://users.telenet.be/Emmanuel.Gustin/fgun/fgun-pe.html

 

Do not Factor in chemical energy. 

 

The author details his methodology:

 

 

The quality factor Q is a standard that Russian designers have been using to evaluate and compare guns. Basically, it is a power-to-weight ratio: The kinetic energy at the muzzle (which is one half the projectile weight multiplied with the square of the muzzle velocity) multiplied by the rate of fire in rounds per second, and divided by the weight of the gun.

 

 

The factor M is another quality factor: The mass output, divided by the weight of the gun. The mass output is the weight of the projectiles, multiplied by the rate of fire in rounds per second.

 

I would use Tony's latest article as being more factual for determining both Q and M of these weapons.  Tony does a crude method of factoring in the chemical energy of the cannon rounds to the equation and not just the kinetic energy.

 

In fact, Tony even includes some of Hennings calculations which are very good.

 

 

The way of calculating the chemical destructiveness is too crude. It is suggested that instead of just adding an arbitrary percentage to the kinetic destructiveness depending on the percentage weight of HE/I filling, an energy calculation should be produced. This would calculate the kinetic energy of the projectiles (in joules) at some typical combat range, then add to this a calculation of the chemical energy (also in joules) contained within the high explosive (if any).

There is a lot of merit in this suggestion, which is more scientific in its approach. However, there are some drawbacks also. First, there is the question of what constitutes a typical combat range. And whatever range was selected, the kinetic energy with which the projectiles struck the target would vary considerably depending on whether the engagement was a tail chase, a beam attack or a head-on attack.

Second, there is the comparison between the various HE and incendiary compounds used. Some of the information required as to their chemical energy is difficult to obtain, and in any case the filling of some shells varied through time, in ways which have not always been recorded.

The final response is the simplest: this approach, while affecting the relative scores of some of the projectiles, doesn't actually change the 'order of merit' very much. Basically, the lower-powered AP or small-HE-capacity cannon shells (which derive most of their effectiveness from kinetic energy) tend to show up as less effective than in Table 1, while the high capacity HE shells show up as being more effective. As these types were typically mixed in an ammunition belt, the net result is no significant change in the rankings.

Henning Ruch has done some calculations on the basis of the 'kinetic+chemical energy' equation and compared the results with those in Table 1. If the .50 Browning is taken as the baseline and given a score of 1.00, the following are some results for other rounds: As you will see, the 'total energy' calculation as much as doubles the performance of the high-capacity cannon shells, while reducing by as much as a quarter  the score of the AP projectiles. [Table amended and extended 25 January 2009]

 

http://www.quarry.nildram.co.uk/WW2guneffect.htm

[JG1_Pragr]

Sorry then. According to the link you posted in your previous post I thought you're talking about Tony Williams table.

[Crump]

No problem at all and I was not offended.  I just realized my first post was not clear and we had a misunderstanding.

 

 

It is a BBS and not the best way to communicate so misunderstandings are bound to happen especially with complicated subjects.

[VeryOldMan]

You know that is the instructions for the M2 MG-AW.  It is Operator's Manual.

 

There is no "IF" to it, that is how they were trained to operate the weapon and the engineering limits of the design.

 

 

My statement is a generalization, as in If ALL guns  were  that bad regarding time between bursts...     In not a single  pilot biography i saw any  statement about waitign half a minute to fire again!!!

[Crump]

 

 In not a single  pilot biography i saw any  statement about waitign half a minute to fire again!!!

 

Most do not talk about pre-flight inspections, squawk procedures, or standard patterns.  That does not mean they ignored them.

 

You do realize that 75 rounds is ~6 second burst.  That is a long time to be holding a trigger down much less being able to keep a gun site on an aerial target for such a long period of time. 

 

 

 

For example,

 

Firing six "short burst's" (~1 sec) does not require a 30 second waiting period by the table, it is just counted as a single 75 round burst since the operator did not cool the gun down between burst's.  Is the weapon going to break?  No. 

 

In fact the table allows for 150 rounds to be fired without danger of a cook off.

 

That roughly equals 12 seconds of holding the trigger down.

 

 

I don't think the issue is the pilot stories or the Operating Instructions but rather the game player expectation. 

It comes down to who is more credible?

 

The Operating Instructions or gamers?

[JtD]

So, essentially you have no clue what the pilots did in the war. You just say they did it like the manual says because the manual says so. And everybody else is wrong.

 

How many occasions of WW2 aircrew violating instructions and regulations do you want me to post before you drop it?

Edited September 27, 2013 by JtD

[VeryOldMan]

Most do not talk about pre-flight inspections, squawk procedures, or standard patterns.  That does not mean they ignored them.

 

You do realize that 75 rounds is ~6 second burst.  That is a long time to be holding a trigger down much less being able to keep a gun site on an aerial target for such a long period of time. 

 

 

 

For example,

 

Firing six "short burst's" (~1 sec) does not require a 30 second waiting period by the table, it is just counted as a single 75 round burst since the operator did not cool the gun down between burst's.  Is the weapon going to break?  No. 

 

In fact the table allows for 150 rounds to be fired without danger of a cook off.

 

That roughly equals 12 seconds of holding the trigger down.

 

 

I don't think the issue is the pilot stories or the Operating Instructions but rather the game player expectation. 

It comes down to who is more credible?

 

The Operating Instructions or gamers?

 

 

geez I dont think you GET what I am saying. I am not saying anythign is wrong here dammit. I am saying we need data  of other cannons to compare, because   we have none from pilot statements.

 

Why in hell people always  try  to see a problem   and a   conflict on everyone's responses in  this forum?

[Gunsmith86]

You guys all realize that the table for that .50 MG is for ground use. The gun in the P 51 Mustang cools much quicker than the gun on ground because of the airflow it makes a huge differnce if you move with +400 KM/H. There was no danger of killing the barrel with the limited ammunition they had on their planes.

Edited September 27, 2013 by Gunsmith86

[Crump]

 

You guys all realize that the table for that .50 MG is for ground use

 

 

No, it is straight out of the M2 MG-AW Operating Instructions.  If you read the underlined portion you will see it agrees with the table!!

Edited September 27, 2013 by Crump

[Crump]

Here is the entire manual in the 1940 edition:

 

http://digital.library.unt.edu/ark:/67531/metadc29988/m1/8/

 

 

 

 

To make the relevant parts easier to find...

 

 

Edited September 27, 2013 by Crump

[Talisman]

Here is the entire manual in the 1940 edition:

 

http://digital.library.unt.edu/ark:/67531/metadc29988/m1/8/

 

 

 

 

To make the relevant parts easier to find...

 

 

M2 AW cooling.jpg

The text appears to be talking about the "flexible gun" used in the fuselage.  Are there a different set of notes for guns used in the wings?  Sorry if this is a daft question but I have not seen the figs 4 and 5 referred to.

 

Edit:  Just noticed from another post that wing guns are classed as fixed guns, so presume that the cooling effect in the wings might be a bit better.

Edited September 28, 2013 by 56RAFTalisman

[Crump]

 

The text appears to be talking about the "flexible gun" used in the fuselage

 

 

Nope, read it again.

 

It does not matter the method of mounting or whether the gun is fired on the ground or in the air.

 

The burst limits are the same.

 

The only time the burst limits change is for synchronized mounted weapons that are pre-heated by the engine.  In that configuration, the burst limits are more restrictive.

Edited September 28, 2013 by Crump

[Gunsmith86]

Thanks missed that part its really the one for the aircarft gun.
Just one point is not right in that manual that a barrel which is cooled by airflow makes only small difference to one that is not cooled by airflow. Here is the manual wrong!

For example: Why use a CPU fan on your PC if it makes nearly no difference if ther is no airflow?

I can also provide a better example at my private 100m shooting range if necessary.

 

Some more info not in the manual:

Here are some things that changed during production which made longer fire rates without danger posible.
Aircraft guns were issued with four spare barrels owing to their high wear-out rate, due to the light barrel and high rate of fire in action.
(It is worth noting that more than 4,800 machining procedures, made on 2,000 milling machines, lathes, and other machines were required for a single gun.)
Cost was eventually reduced: in 1941 an aircraft gun cost $723, in 1944 just $270. Production quality was also improved. In 1944,
Stellite liner inserts were introduced to reduce bore erosion, and extended down the first 7in of the chamber and bore. Chromium-plated bores were
introduced later to extend barrel life to about tree times of the older ones.


During training, a 75-round (five-second)burst was the maximum permitted from a cold gun. One minute after the first burst, firing could be
resumed at up to one 20-round burst per minute. In combat, of course, higher rates were used, but it was warned that unrestricted 75-round bursts would sooner or later overheat the barrel and could result in stoppages or runaway firing. Spare barrels were not carried aboard bomber aircrafts.

Strafing attacks
For fighters equipped with .50-cals, ground strafing was a very different
experience to bomber gunnery. Fighters flew relatively low and at a fairly
shallow angle when strafing area or column targets, such as scattered
troops or vehicle convoys, to spread their fire over as large an area as
possible.
When attacking point targets, such as gun positions, parked
aircraft, or defensive structures, they approached from a steeper angle and
from a higher altitude to concentrate their fire on the point. Motion pictures do not do the effects of strafing
justice. A P-47 Thunderbolt firing a 30-second burst from its eight .50-cals put out approximately 2,000
rounds, of which about 400 were tracers. The noise of firing was a deep
buzz, and individual shots could not be distinguished. It was not lines of
spurting dirt that marched across the ground, but virtually an explosion
of bullet strikes sprayed almost instantly into the ground or target. Even
at 200mph, pilots saw the hellish carnage they created. After long bursts
from synchronized guns, the bolt had to be locked to the rear for two
minutes to prevent cooked-off rounds from striking the propeller blade.
Airflow helped to cool overheated aircraft guns.

 

The German MG 131 13mm had a barrel life of 17000 rounds when fired with short bursts.

Edited September 28, 2013 by Gunsmith86

[Crump]

 

Here is the manual wrong!

 

 

The manual is not wrong.

 

Look at the materials a CPU is constructed of and a Machine gun barrel....check out the specific heats.

[Gunsmith86]

It is wrong.

We test barrels with diffrent ammunition to find out which ammunition works best on that gun. Before i can use the next ammunition i have to get the barrel back to normal temperature to get comparable results. We use a fan for that while One gun is cooling i make one test with another gun after that i change the two guns and shoot the second ammunition while the other gun cools down. Whitout that fan i have to shoot 4 guns to get the first one back to normal temperature. We make that on 1000 guns each year so i must know a little bit about what i am telling you.

Of course you can also thrust the manual but they sometimes have mistakes.

 

If you are intersted there are some good books:

Alos you can find some info about temperature and barrels in the RHEINMETALL book called "Waffentechnisches Taschenbuch" ("weapons technology") but its hard to get one of these and they are only in german.  Another good book serie is called Waffen revue they had a very good  article about the Lewis gun and how effictive the cooling is.

 

Edited September 28, 2013 by Gunsmith86

[Crump]

The manual is not wrong.  It is just that simple.

[Finkeren]

I might be ignorant about some details about aircraft construction, but how exactly do you get airflow over the .50 cals in, say, the wings of a P-51?

 

On many US fighters of WW2 the guns are almost completely burried in either wings or fuselage with no visible intakes or vents to allow a significant airflow over the barrel nor the breech.  

 

This leads my to another question: On the P-47 the 4 .50cals in each wing have different portions of their barrels exposed. Wouldn't that result in dissimilar cooling rates due to different airflow, and wouldn't that be kind of a problem?

[79_vRAF_Friendly_flyer]

largest advantage  wa sthe ammunition as  you posted and  the    operational advantages that you cited as small. Production, duirability etc.. those are  HUGELY important isn a long campaign  and are the difference between the gun being there to fire .. and not being  there.

 

That is main reason  US used those .50.  Easy to produce, already mass produced and reliable. That does not win a combat, but wins a war.

There are some argument over that. According to the post-war official US evaluation, the reason they retained the old M2 was more a question of failing to produce a workable Hispano version. For reference, see. http://ibiblio.org/hyperwar/USN/ref/MG/I/

[Crump]

 

JtD says:

So, essentially you have no clue what the pilots did in the war. You just say they did it like the manual says because the manual says so. And everybody else is wrong.

 

 

I am sorry, I had you on ignore and did not see your reply.

 

If you read the post's above it you will get your answer:

 

 

Crumpp says:

 

 

Firing six "short burst's" (~1 sec) does not require a 30 second waiting period by the table, it is just counted as a single 75 round burst since the operator did not cool the gun down between burst's.  Is the weapon going to break?  No. 

 

In fact the table allows for 150 rounds to be fired without danger of a cook off.

 

That roughly equals 12 seconds of holding the trigger down.

 

 

I don't think the issue is the pilot stories or the Operating Instructions but rather the game player expectation. 

 

It comes down to who is more credible?

 

The Operating Instructions or gamers?

 

 

Crumpp says

 

VeryOldMan,

 

If the topic was hunting rifles, I would agree.  However, we are talking large caliber machine guns.  Step your barrel life expectations down tenfold.  Heat is what kills barrels.  Machine guns build up heat extremely fast.  A brand new barrel will not make it to 1000 rounds if the weapon is mistreated thru improper operation.  By that, I mean the operator holds the trigger down and does not observe the firing limitations.

 

The larger the caliber, the faster the ROF, the shorter the barrel life.