Rates of fire - tanks vs AT guns

[Guest Mike]

Does anyone have any information on rates of fire for tank guns derived from or the equivalent of ground mounted AT guns?

Eg the Pak 40 vs Pz4 F2 onwards vs Marder series vs Hetzer vs JgdPz-4L48?

Tiger 1 vs FLAK36

Tiger II vs PAK43

Firefly vs 17 pdr

etc

Thanks

[JonS]

ISTR that the firefly suffered especially, as - among other things - the gun had to be rotated 90° to get it in the turret, which made loading, unloading, and working the breech difficult.

No specific numbers though, sorry.

[Guest Mike]

Yes - Wiki says so too

Also there are lots of comments around about the Hetzer's internal arrangements, and the Tiger II having a slow rate of fire due it's 20kg ammo - but what was it compared to the PAK43 which used hte same ammo outside a tank??

[dieseltaylor]

The tank may have some instantly ready shells to hand so for a short period no problem. I would expect the gun crews to have a higher rate of fire generally as they have more room to move, the facility to pass shells to each other, and swop roles. Of course if there is any return fire then I would expect the ROF to drop off quite quickly.

So the answer is - it depends : )

[John Kettler]

Stalin's Organist,

May I suggest AH's Tobruk, designed by Operational Analyst Hal Hock? The game wasn't the most playable, especially before doctrine was added, but the underlying research was extensive.

One of the topics specifically addressed was the one you'd like answered. The general rule was that the antitank gun had a marked ROF advantage over it's equal sized tank mounted counterpart. This was because there was more room to serve the gun and more men to move the ammo, clear brass away, etc. The gun has the signal advantage of not being in motion or jouncing up and down, to and fro, unfortunate conditions frequently encountered inside a tank in combat. Until such time as it comes under effective fire, the antitank gun will fire faster, reload faster and, other things being equal, be able to replenish its initial ammo stock faster, too, as opposed to doing gymnastics getting into ammo lockers, prying up floorboards and such, all in a lurching, fume filled, blazing hot oven. Also, it's harder to spot than the tank and much harder to hit. Even worse when camouflaged properly. See, for example, German AARs on locating Pakfronts during Fall Zitadelle.

One of my favorite rough and ready "tank sims" I read about went something like this. Take a piece of paper and poke a pinhole through it. Now, look through it. Can't see much, can you? That's the buttoned tank at rest. For sighting while moving, try jumping up and down while repeating the exercise. Loaders get to heave sandbags while not looking, yet still jumping up and down.

You now understand why no less an authority than Panzer ace Michael Wittmann deemed the antitank gun far more dangerous than an equivalent tank. It was hard to spot, even after firing, and not easy to kill, especially if dug in. Do not let your CM experience to the contrary fool you on this score, for the historical accounts are full of examples in which tank after tank blew up, but no one could tell where the fire was coming from.

No Borg spotting in WW II!

Regards,

John Kettler

[undead reindeer cavalry]

Originally posted by Stalin's Organist:

Also there are lots of comments around about the Hetzer's internal arrangements, and the Tiger II having a slow rate of fire due it's 20kg ammo - but what was it compared to the PAK43 which used hte same ammo outside a tank??

PaK43 could fire faster than was otherwise practicable (the dust kicked up would block the vision and so forth). the rate of fire was thus officially limited to 10 rounds / minute.

heavy PakS and especially FlaKs had large crews and they thus could fire as rapidly as 20 rounds / minute.

[John D Salt]

Originally posted by undead reindeer cavalry:

</font><blockquote>quote:</font><hr />Originally posted by Stalin's Organist:

Also there are lots of comments around about the Hetzer's internal arrangements, and the Tiger II having a slow rate of fire due it's 20kg ammo - but what was it compared to the PAK43 which used hte same ammo outside a tank??

PaK43 could fire faster than was otherwise practicable (the dust kicked up would block the vision and so forth). the rate of fire was thus officially limited to 10 rounds / minute.

heavy PakS and especially FlaKs had large crews and they thus could fire as rapidly as 20 rounds / minute. </font>

[undead reindeer cavalry]

Originally posted by John D Salt:

So I doubt that the size of the rounds is much of a problem until you get to something quite a bit bigger.

yes, the crews could have easily fired the guns faster than they were allowed to.

[Guest Mike]

Naval guns usually have the shells delivered quite close to the breech by machinery tho. AT guns have a similar effect from having multiple ammo handlers to get it from box to breech.

The poor ol' tank gunner has to get his from ready-use racks and other storage wherever it has been crammed into his already restricted hull....

In any case there's plenty of anecdotal stuff out there & I was intereted in any "official" figures.

[JasonC]

I second John's point. I've personally fired 6 rounds per minute of 155mm howitzer with separate loading ammunition. The rounds weigh 98 pounds, and this tires you out fairly rapidly, but when you need ROF you can get it. The mission goes down-range and then you rest, like a breather between weight-lifting sets.

There are some safety issues with firing very fast with separate loading ammo. The powder bag goes into an unswabbed breach, and there can be embers of unconsumed powder from the previous round, still in the chamber - though the flash pad is only at the rear of the powder bag, and the breech is closed within a split second of the powder going in, and embers themselves are rare to begin with.

With semi-separate loading ammo, as with the US 105mm, the ammo team does all the round prep and the loader doesn't have to worry about such things. The rounds are only 33 pounds. You can readily push a dozen a minute through one firing tube with those.

These rates vastly exceed the rated *sustained* rates of fire for the guns. That rate is set not by crew ability or the time and motion mechanics of feeding the gun, but by its long term cooling ability. Rates of fire in excess of the sustained rate heat the barrel. If kept up long enough, this can expand the barrel enough that "windage" arises, and range drops. The tube is "burnt out".

The recoil systems, hydraulically powered, are also tortured by sustained fire in excess of the designed rates, and can break down under the strain (losing hydraulic fluid, failures to fully return to battery, etc).

Less common but still a hazard are breech problems, which can come from rounds fired with the screw lock at the back of the gun being less than entirely locked tight when the round is fired. Repeated shots like that can be dangerous (burst guns are rare but possible), and can lead to a jammed breech that cannot be opened, or (less common) refuses to lock closed.

Of these points of failure, the first to give out in a hot gun firing situation is usually the loader's arm muscles. But loaders are readily relieved, and that can push you into the other modes of failure. Dropping the fire rate to the sustained level (and water-cooling the barrel, sometimes) can keep it up longer until other systems give. Usually, ammo will give out first, or the crisis at the other end passes.

In the short run, it is quite easy to "smoke" the rates of fire you see in CM. All the other limits kick in on much longer time scales - loader fatigue on 15-30 minute time scales (think, a free-weight session at the gym), tube burn-out on hour time scales, the others on day time scales or a few tubes in a battalion on hour scales.

[undead reindeer cavalry]

Originally posted by Stalin's Organist:

In any case there's plenty of anecdotal stuff out there & I was intereted in any "official" figures.

10 rounds per minute for PaK43 is an official figure.