30mm Mk108

[230G]

Why does the 30mm have such a large dispersion pattern?

 Being a handloading/rifle shooting nut, I can tell you that some cartridges are inherently more accurate than others. The .50 cal. Browning is one of the best; espaecially in shoulder fired firearms. Ditto for the 6.5x55mm Swede. The .222 Remington, the .22 & 6mm PPC. I know this both from experience and from reading and talking at length to other shooters.
      From what I've read, the 20mm Hispano is an "accurate" round, while the Luftwaffe cannon's were inaccurate. I know I have a terrible time hitting with the Luftwaffe planes compared to the British planes.
  Also, as someone has already mentioned, the 30mm's with their low velocity have a much more arched trajectory than their counterparts. If you don't believe it, just use the ".target" (is that right?) function and compare the 30mm to others at various ranges.
  230G

[GScholz]

Simple. Just hold your fire until the target is this...

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 ... big and the ACME automatic hand grenade dispenser should work just fine.

[Charge]

"Maybe the low velocity doesn't allow for a high rate of spin when fired. Maybe less twist in barrell.?"

The rifling in the barrel is designed so that it gives the optimum rotation to the grenade or bullet with a certain muzzle velocity. If the bullet is slower for some reason it gets inaccurate as it starts its flight with too slow rotation and if the bullet is very much too fast for the rifling it probably may "cut through" damaging eventually the barrel and the bullet. If a grenade has a sealant ring around it the situation may be worse if the ring gets separated from the grenade because of too fast velocity. The ring gets stuck in the rifling causing an explosion when next round is fired, or the ring flies out of the barel after separated with the grenade thus causing a very low velocity shot.

That is why there is not much variation allowed in muzzle velocity even for different kinds of grenades. So for a lighter grenade the rotation is not necessarily enough causing it to diverge from its flight path is some stage of its flight, while the for the other type of grenade the rotation may be just right giving it excellent accuracy through its effective flight path.

That is IF I remember correctly...


-C+

[Furball]

Rifling on Mk108

[Flyboy]

thats a greatr picture

Me262?

[Furball]

yup

[OntosMk1]

Urchin, the only thing i can possibly think what might have happened is that your tail section hit the collision "bubble". As far as the 30mm hit to the nose, It did trash the engine. Now, the 30mm hits to the wing area shouldve blown the wing OFF. I've got footage of 109s attacking a SPit from dead 6 position and SPit takes several 30mm hits to tail section and wing root. You see half the tail simply disappear and sevear damage to the wing root and trailing edge....

 Ive taken down multi engine planes with just two hits from the 30mm but then had to use up almost every round to bring down some fighters. I know they were 30mm hits because that was the only weapon firing....So who knows:confused:

[Furball]

hit an f6f with osty today, in the nose - only gave him oil leak.  It didnt even kill engine.

[230G]

The rifling in the barrel is designed so that it gives the optimum rotation to the grenade or bullet with a certain muzzle velocity. If the bullet is slower for some reason it gets inaccurate as it starts its flight with too slow rotation and if the bullet is very much too fast for the rifling it probably may "cut through" damaging eventually the barrel and the bullet.

  Mmm....not exactly. Rifling is rated in turns per inch. The optimum amount of rifling required to stablize a bullet is determined by a ratio of the bullet diameter to the weight (hence length) of the bullet. For example, a .22 Long Rifle, 40 gr. bullet  fired from a 6" handgun barrel develops a velocity in the 1000 fps range. This bullet requires a twist of about 1 turn in 14"-16". A large volume .22 caliber rifle firing a 40 gr. bullet at 4000 fps will require the same amount of twist to stabilize the bullet. In short, the rotation is the same regardless of the beginning velocity.
     I own .35 caliber pistols (.357 Magnums, 38 Specials) and a .35 caliber rifle, and their twist is almost identical even though the rifle fires the bullets, in some cases, twice as fast as the handguns.
     I've fired rifles that didn't have fast enough twist for the bullet loaded and they're wildly inaccurate. On the other hand, I've fired rifles with more twist than necessary for a given bullet and the bullets do just fine. The only exception is that in some cases, bullets fired at very high velocity through a barrel with fast twist will disintegrate due to high rotational forces.
        Unless you're firing bullets made of metal that is nearly as hard as the barrel, you'll have to fire many, many rounds to damage the barrel.
       Maybe the Germans had an incorrect rate of twist in their MK108 barrels.
FWIW
  I hope this little lesson in ballistics wasn't TOO boring.
  230G

[Crumpp]

The outstanding performer is clearly the German 30 mm MK 108, which achieves ten times the destructiveness of the .50 M2 for only twice the weight. It makes a particularly interesting comparison with the MK 103, which fired the same M-Geschoss projectiles. The MK 103 gains an advantage because of its higher velocity, but loses most of it due to its lower rate of fire, then is finally eclipsed in efficiency because of its much greater weight. No surprise that the Luftwaffe considered the MK 108 their premier air-fighting gun despite its low muzzle velocity. The Me 262 jet fighter, with four of these guns clustered in the nose, completely outclassed the firepower of every other WW2 fighter.

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

Mk 108 comes in first in overall effectiveness.

Let's assume that, with the benefit of hindsight, we could specify the ideal gun armament for a Second World War fighter plane. What might it look like?

There are no close matches with our "ideal" gun - there were very few 30mm cannon - but the closest actual match was the IJA's Browning-type Ho-155, which fired at 450-600 rpm and weighed in at 60 kg. The IJN's Oerlikon-pattern Type 2 weighed 42 kg, although it only fired at 400 rpm. The short-barrelled German MK 108 weighed 60 kg and fired at 600 rpm. On balance, a target of 60-70 kg looks entirely achievable.

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

And Number 2 for the idea fighter armament of WWII.

Crumpp

[storch]

I think Urchin is correct.  Last night in the CT in a G6 while firing on a Yak at D200- I observed several hit sprites but no damage,  I circled and attacked again and finally after many hits shot it down.  I landed reupped and shot all the 13mm so I only had the 30mm with ammo and went hunting.  I shot down a P40 with 4 pings and an La-5 with 3 pings.  I also had multiple hits maybe as many as 10 on a Yak before running out of ammo and RTB'n  I received an assist while on final for the Yak.  You guys may want to look at the damage model on the tater guns.  Maybe the shots are ricochetting off?

[Krusty]

Storch if you got that on film please send in to htc as proof of bug of some sort. I know for a fact 20mm will kill in 2-3 hits in the right place, but to need 3 30mm? 5 30mm? That's wrong.

[GODO]

Originally posted by Krusty
I know for a fact 20mm will kill in 2-3 hits in the right place

Hispanos, may be. I need LOTS of 20mm flashes to do any visible damage with 151/20s.

[Gman]

I've noticed the same thing, of 50 or so kills in AH2 beta and now with the 30mm, probably 15 to 20% have survived a single ping, which only happened once in AH1 since beta, at least to me.

[Slobberdonkey]

still depends on the plane and point of impact somewhat.  I remember several occasions in AH1 where I took a 30mm hit from a Me262 and survived in a p47-d11 or F4U-1.  Also even took some 37mm ostwind hits in the p47 and lived to tell about it.  Typically losing a wingtip or dead engine.  However if hit in the tail it was always a death