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L/71, L/52, etc. = what???


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I need to buy an army for an axis assault I'm PBEMing with, and I just realized - I have no idea what 'L/71' and all those other numbers by a tank's gun when you purchase it. So, what do they mean?

Oh, and is self-propelled artillery good? I'm never purchased one, how quickly do they fire? will they destroy a building in one hit? is it like a truck with a missle on it, or what?

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Originally posted by FragerZ:

I have no idea what 'L/71' and all those other numbers by a tank's gun when you purchase it. So, what do they mean?

It stands for the length of the barrel, but that figure is derived by taking the shell's diameter and multiplying by the number listed. For instance, the standard Sherman fields a 75mm L/38, which works out to a barrel length of about 2850mm (75mm x 38) or a little over 9 ft.

Oh, and is self-propelled artillery good?
Depends. Are you going up against a battalion of bellicose penguins?

I'm never purchased one, how quickly do they fire?
Chances are it will be one milisecond slower that whatever is firing at them. Telle est guerre !

will they destroy a building in one hit?
Either that or rearrange the furniture into some faggy, art-deco motif.

is it like a truck with a missle on it, or what?
Worse, its a frickin' shark with a laser beam, with a ninja riding on top, and the ninja's hair is on fire.
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Wow, kinda harsh JoMc67.

FragerZ,

L/71 has to do with the barrel length, the higher the number the longer the barrel. The longer the barrel, the more accurate the gun. All approximations of course.

SP arti units are a mixed bag. The 150's are great against soft targets but not so good against armor. Think high explosive and generally not so accurate. You need to look at ammo type to see if you have a chance against armor. But the game chooses which ammo type to load so that part is really out of your hands. Generally the 75mm and 88mm are your most effective anti-tank weapons but 50mm can be used with caution.

Hope that helps.

......and what Kingfish said :D

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Originally posted by mike_the_wino2:

Wow, kinda harsh JoMc67.

FragerZ,

L/71 has to do with the barrel length, the higher the number the longer the barrel. The longer the barrel, the more accurate the gun. All approximations of course.

SP arti units are a mixed bag. The 150's are great against soft targets but not so good against armor. Think high explosive and generally not so accurate. You need to look at ammo type to see if you have a chance against armor. But the game chooses which ammo type to load so that part is really out of your hands. Generally the 75mm and 88mm are your most effective anti-tank weapons but 50mm can be used with caution.

Hope that helps.

Good answer! I'll also add that the coloured bars on the user interface give a good indication of penetrative and protective abilities of the guns and armour in the game at a glance, also, as does hitting the Unit Info key.

Welcome to the forum, by the way, FragerZ. Always good to see new fans of the franchise here.

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Rates of fire

150mm guns - 2 rounds per minute

105mm guns - 4 rounds per minute

smaller - 6 rounds per minute

20mm autocannon - 10 rounds per minute

All approximate, somewhat affected by crew quality, time spent traversing to acquire targets, etc.

150mm HE will destroy small wooden building with a single shot, small stone with 2-3, and entire city blocks in 2 minutes.

105mm HE will destroy small buildings in one minute, larger wood in the second. Full city blocks will take longer, but nobody inside will enjoy it.

Smaller HE down to 75mm will generally pin infantry or gun targets with the first close hit, and leave them pinned or panicked at the end of the first minute. But they will generally only lose 1-2 men, the effect is mostly to morale. Good enough anyway, and another minute of fire will typically break them and send them running.

HE smaller than that is not particularly effective, and will mostly just pin the target as long as the fire is kept up.

For "HE chucking" to kill infantry, the German's best choice is the StuH, which sports a 105mm gun under full armor. The rounds are effective against all infantry targets and the ROF is decent. They will KO light armor or tanks with flank shots using ordinary HE. They sometimes get a few HC rounds (high explosive anti-tank), which will kill most enemy vehicles if they hit. Not the most accurate, highest velocity weapon, but adequate against one tank in a pinch.

The open topped SPA can be effective but can also be harder to use. The Hummel is the best of those, since direct fire 150mm HE is simply devastating. But quite vulnerable to any sort of reply fire, beyond small arms. Wespes (105mm) aren't as useful, with a limited ammo load and all the vulnerability - take a StuH instead.

The poor man's HE chucker is the SPW 251/9 halftrack, armed with a short barreled 75mm gun. Its antitank ability is modest - only going to kill light armor really. Maybe a medium tank with a flat side shot using HC, on your best day. Very thin armor, especially the sides, make them vulnerable to even small ATRs. But they are cheap and use "vehicle" points, not armor.

To keep them alive, try the "keyholing" tactic. That means peek between obstacles - a pair of houses e.g. - so only a narrow pencil into enemy areas can be seen. That keeps most enemies from shooting back at you. Line it up so you can see your target and nothing else, and back away to reposition after a minute or two.

None of the above can fire indirect - they all need to see their target. In CM, only mortars can fire without seeing their target (and artillery FOs for off-map guns). It requires an HQ spotter in command distance, but if the HQ can see the target, the mortar can fire, without being exposed itself.

I bring that up for the last good German HE chucker, the SPW 251/2, halftrack mounted 81mm mortar. Same weapon as the ground mortar, but about twice the ammo (!), plus armor and speed. These are very effective at killing enemy guns, since you can set up shots on them without reply and guns typically can't get away. Fire for a minute or two and count on the target being pinned, and switch to another. Have a machinegun or something keep up the fire to "maintain the pin", preventing or slowing "rally".

StuHs and SPW 251/2 are excellent weapons, robust and able to dish out plenty of hurt over their ammo loads, if you are careful enough with them to keep them alive.

For efficient tank killing, on the other hand, the "big cats" are darn good at it. That means Tigers and Panthers. Also good at it are dedicated tank destroyers with well sloped front armor, like the Jagdpanther, Jagdpanzer L70, or the poor man's version, the Hetzer. All can "bounce" many enemy antitank rounds from their frontal armor, as long as you keep them facing the target. Their own guns tend to be very lethal (though the Hetzer is weak compared to the others, enough to make a difference late in the war when they are out).

In the earlier war, a popular cheap tank killer is the StuG III G model (or F8), with 75L48 gun and 80mm of frontal armor. This is just enough to "bounce" Russian 76mm cannon fire, while its own gun can kill T-34s and Shermans at a kilometer or more. A big draw with these is how cheap they are - around 100 points, whereas a single "big cat" can run 200-250.

I hope this helps.

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wow, ummmmm, that was a lot more information than I was expecting, I wish that i asked it before -- thanks, I'll buy my armour accordingly.

(I always thought that the higher the L/X, the faster the reloading)

"Either that or rearrange the furniture into some faggy, art-deco motif" lolololol

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Here's an easier answer:

Short barrel guns (i.e; L/11) are good against infantry (HE and C type ammo).

Long barrel guns (i.e; L/71) are good against tanks (AP, T, and HC type ammo).

Just about everybody has "S" ammo (smoke), which can be used to blind the enemy.

As a rule of thumb, the larger the shell, the slower the reload time (i.e; 20mm = fast / 150mm = slow).

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Originally posted by Rankorian:

Well, I have read WW2 stuff for decades, and did not know this. I had gathered that higher numbers meant a longer barrel, which was somehow better--but never understood the exact relationship, nor had completely realized the implications (more length equalling better accuracy, everything else being equal.)

So, thank you FragerZ, and Kingfish. [/QB]

Kingfish gave a good, simple explanation. So lets immidiatly try to complicate it a bit, just for the fun smile.gif

While it is correct that L/x equals barrel length divided by bore diameter, it is not always measured the same. In the US, barrel length was measured as "bore length" i.e. from the front (or inner) surface of the breech block to the end of the muzzle, not counting the muzzle brake. In Germany, they took the measure from the rear face of the breech to the end of the muzzle, not counting the muzzle brake.

What his means is that the Shermans 75mm M3 gun was 37.5 calibers long (L/37.5) if measured in the US, but when the Germans put the measure on it, it was 40.1 calibers long (L/40.1).

And the numbers, even when the measure is the same, can sometimes be confusing. As an example, the Germans had three different 75mm guns of roughly the same calibers length:

- 7,5cm PaK 40 L/46 (i.e. the anti-tank gun)

- 7,5cm KwK 40 L/43 (i.e. the early Panzer IV tank gun)

- 7,5cm KwK 40 L/48 (i.e. the later Panzer IV tank gun

Why three different lengths? Actually, the rifled part of the barrel on the L/46 and the L/43 was exactly the same length, the different comes from the fact that the anti-tank gun had a longer chamber while the chamber on the tank gun was shorter and wider. In the L/48 gun, they lengthened the rifled part of the barrel.

So when you say that the longer barrel has better accuracy (all other things being equal), it is true, but only if the rifled part of the barrel is longer. Having a longer chamber does not add anything to accuracy. So for all intents and purposes, the L/43 gun and the L/46 gun would be equally accurate, while the L/48 would be more accurate than both - at least in principle. smile.gif

cbo

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Just to add to the confusion, a longer barrel does not equal a more accurate gun.

More barrel length typically means a higher velocity. A higher velocity means that time to target is shorter, so to a given range there is less drop and less effect of wind. However, the inherent dispersion of a the gun may well be greater than a shorter barrelled weapon. In fact, a shorter barrel will be likely to be more accurate because it is easier to produce a shorter barrel and the barrel itself will be stiffer.

Given consistant conditions, the more accurate gun will put more rounds closer together, but a higher velocity gun is less sensitive to the conditions.

A lower velocity (shorter barrel) gun generally has lower acceleration loads, so a greater proportion of the shell can be HE rather than structure. Plus, if you can get the range right, hitting a point on the ground is easier with an arcing (low velocity) trajectory than a flat one.

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It does, but the numbers are high. E.g. the service life of a Brit 17 pdr was about as low as they got because of super velocities, and it was something like 400 rounds. (That figure may be for APDS specificially, though, and it might be more like 1000 for AP). Squeeze bore hypervelocity weapons the Germans used e.g. 28-20 swPzB - also had short lives, 300 to 500 shots. A Russian 57mm lasted about 1000 shots. These should be compared to typical lives of 1500-2000 rounds or so for a typical high velocity tank gun, and more like 7500 rounds for a typical 105mm howitzer.

In practice a towed ATG in combat was something of a "throwaway" weapon and would rarely reach those numbers of shots fired. Some tanks would be lost long before reaching them, and would fire mostly HE if they did fire that many shots. In the nature of things, the average tank doesn't knock out multiple enemy tanks (think about it...)

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Originally posted by costard:

I'm enjoying this, thanks guys.

On the subject of barrel design, does a higher muzzle velocity necessarily lead to a shorter barrel life?

I remember reading about the US M107, which was a 175mm field gun used in Vietnam. The maximum range was over 30km, far more than whatever the NVA could deploy against it, and making it the ideal counter-battery and H&I weapon. However, that came at a price, because in order to hurl a shell that far it required extra charges, and thus increased the chamber pressure and barrel wear.

It was estimated that a M107 firing at normal ranges had a barrel life of around 10,000 shots, but if it fired exclusively at extended ranges the barrel would only last 400 before requiring replacement.

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flamingknives,

Our weapon analyst at Hughes was a battleship grog, and he told me that the British, in order to achieve acceptable accuracy on the then new 15" gun, had to reduce the powder charge. Why? To eliminate barrel whip which was excessively dispersing the shots. Taking a few hundred FPS from the muzzle velocity was the difference between accurate naval gunnery and a useless weapon.

Kingfish,

The M107 was the only gun we had in Vietnam which could outrange the otherwise untouchable Soviet supplied M46. Neutralizing something like a dozen of these guns required concerted, integrated effort by both the Army and the Air Force. The M46s were dug in and hard to spot. Remember, this was way before we had the Firefinder CM/CB radars.

Regards,

John Kettler

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Tuning the barrel length - having the end of the barrel lie on a node of the waveform caused by the shockwave of the igniting propellant - should help with dispersion problems. Fullbore (7.62mm) rifle shooters have been doing this for a few years now (as far as I know). I can appreciate why the navy might just adjust the propellant loadout instead.

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Originally posted by JasonC:

It does, but the numbers are high. E.g. the service life of a Brit 17 pdr was about as low as they got because of super velocities, and it was something like 400 rounds. (That figure may be for APDS specificially, though, and it might be more like 1000 for AP).

According to a 17-pdr Mk V manual, the accuracy life of the gun was 425 EFC (Effective Full Charge) rounds.

APCBC Full Charge = 0.5 EFC

APCBC Reduced Charge = 0.03 EFC (doesn't make much sense..?)

HE Full Charge = 0.25 EFC

HE Reduced Charge = 0.03 EFC

APDS = 1 SV (Super Velocity) charge = 0,75 EFC

Smoke = EFC neglible

So converted to rounds fired, barrel life would be between ~14.000 (HE reduced charge) and 566 (APDS) with APCBC full charge giving a life of 850 rounds.

Claus B

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  • 2 weeks later...

Thought you gents would enjoy this - while researching a WWI script, I came across this info for the German Paris Gun, the 256 ton railway monster used during 1918.

"The projectile reached so high that it was the first man-made object to reach the altitude of the stratosphere, thus virtually eliminating drag from air resistance, allowing the shell to achieve a range of over 130 kilometres (80 miles). The shells were propelled at such a high velocity that each successive shot wore away a considerable amount of steel from the rifled bore. Each shell was sequentially numbered according to its increasing diameter, and had to be fired in numeric order lest the projectile lodge in the bore, and the gun explode. Also, when the shell was rammed into the gun, the chamber was precisely measured to determine the difference in its length: a few inches off would cause a great variance in the velocity, and with it, the range. Then, with the variance determined, the additional quantity of propellant was calculated, and its measure taken from a special car and added to the regular charge. After 65 shells had been fired, each of progressively larger caliber to allow for wear, the barrel was sent back to Krupp and rebored to a caliber of 240 millimeters (9.4 in) with a new set of shells."

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Hpt. Lisse,

All true, but the passage failed to note that the Germans were forced, for the first time in standard history, to factor in Coriolis Drift generated between the time the shell cleared the muzzle and when it hit. This was because the "hang time" was

long enough that the Earth's rotation below the shell during its transit became of military significance.

Regards,

John Kettler

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Originally posted by JoMc67:

FragerZ,

Seriously, If you dont know anything about these units you dont belong in the game.

JoM67

Seriously, do you think we're all linguering here to write endless posts on matters we are all already well familiar with? This forum is all about the exchange of knowledge. It always was. You might want to reconsider your presence here, if this offends you.

Sinceriously

Dandelion

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