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BillSwagger
07-22-2009, 10:05 PM
i read this article that was linked from another post in a thread on the topic of ammunition load outs and effectiveness.

http://www.geocities.com/CapeC...n-fi.html#comp-table (http://www.geocities.com/CapeCanaveral/Hangar/8217/fgun/fgun-fi.html#comp-table)

Part of me wonders how accurate certain planes could be firing large He rounds with relatively lower muzzle velocities.

The article goes into to it in more detail..

Waldo.Pepper
07-23-2009, 01:23 AM
Originally posted by BillSwagger:
Part of me wonders how accurate certain planes could be firing large He rounds with relatively lower muzzle velocities.

http://img.photobucket.com/albums/v516/WaldoPepper/book/410.jpg

Consider the bullet drop of the BK 5(actually, 'shell' or 'round' drop more precisely). I can't imagine how anyone was expected to hit anything at the long range that was considered safe from return fire.

http://img.photobucket.com/albums/v516/WaldoPepper/book/410-2.jpg

Maj.Kaos
07-23-2009, 07:52 AM
More details anybody?
http://www.quarry.nildram.co.uk/WW2guneffect.htm

Already posted a couple of years ago, here is a fresh one for the newer fans.

Given the desperation of the Luftwaffe to try anything that might scratch an enemy bomber, I am surprised that they didn't fit one of the captured American bombers with a PaK43 88mm firing through the nose. They could have trailed the bomber formations and sniped the bombers one by one from 3km out. http://forums.ubi.com/images/smilies/blink.gif

Esel1964
07-24-2009, 12:04 AM
Velocity isn't everything,by any means!
The energy delivered upon impact is the major factor.

As an example,look at the stopping power of a .45 ACP 230 gr. FMJ (the grains means the weight of the projectile in grains of wheat);eventhough it's a relatively slow round-it's still one of the best 'man-stoppers' around,even when compared to a 9mm or .40 S&W hollow point.

Granted velocity can equate range(in some cases),but you have to try to take the tail-gunner out first;which was often the case.

Just a few thoughts. http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif

BillSwagger
07-24-2009, 01:23 AM
Originally posted by Esel1964:
Velocity isn't everything,by any means!
The energy delivered upon impact is the major factor.
:

There is no doubt a large He round can blow a big hole in a plane on impact. I just wonder how easy is it to land one of those shells from beyond 200M??...beyond 100M??

or ....while turning???

JtD
07-24-2009, 11:21 AM
Most of the primary WW2 airborne guns are within 15% of muzzle velocity. At 200m the difference in flight time is like .27 to .31 seconds or so, not that much.

BillSwagger
07-27-2009, 03:28 AM
I also was giving the thought of the 8 50 cal guns, and how much energy they are sending at a target.

Granted there bullets aren't like an He round that leaves a large hole, but i would imagine its like a shot gun effect. If you tried to tell me a 10 gauge shot gun leaves 20 small bb sized holes in its target, then id know you were full of it.

I would think 100 rounds per second hitting in the same 3ft diameter are very deadly, as they were.

M_Gunz
07-27-2009, 05:00 AM
Originally posted by Esel1964:
Velocity isn't everything,by any means!
The energy delivered upon impact is the major factor.

As an example,look at the stopping power of a .45 ACP 230 gr. FMJ (the grains means the weight of the projectile in grains of wheat);eventhough it's a relatively slow round-it's still one of the best 'man-stoppers' around,even when compared to a 9mm or .40 S&W hollow point.

.45 ACP has 800 ft-lbs kinetic at muzzle. If it stays in the target then all of that is delivered.
If the bullet goes clear through the target then only a fraction of the momentum is transferred to the target.
That's also why a big gauge shotgun slug is more effective at close range against large game than a high power rifle.


Granted velocity can equate range(in some cases),but you have to try to take the tail-gunner out first;which was often the case.

Just a few thoughts. http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif

Range, less drop and windage and lead (on a moving target) to be in error.
You also get hydrostatic shock from high velocity bullets at least if they are shaped right or hit a bone.

M_Gunz
07-27-2009, 05:12 AM
Originally posted by BillSwagger:
I also was giving the thought of the 8 50 cal guns, and how much energy they are sending at a target.

Mike Williams site tells you just how much at muzzle. I tried to get him to put up range info but he misunderstood why, oh well.


Granted there bullets aren't like an He round that leaves a large hole, but i would imagine its like a shot gun effect. If you tried to tell me a 10 gauge shot gun leaves 20 small bb sized holes in its target, then id know you were full of it.

That's why they make buckshot and slugs! LOL! Please tell that birdshot is anywhere near as effective at even 30 ft!


I would think 100 rounds per second hitting in the same 3ft diameter are very deadly, as they were.

Of course. The measure works by total effect. But 100 rounds into a wingtip won't destroy the plane any more than 4 30mm
shells to like parts of the plane.

The thing is you should check Mike Williams site just to see how much bang the different HE shells deliver by explosion
alone compare to a single 50 cal at the muzzle, which does lose a good bit of energy in 200m travel btw... kinetic energy
is by the square of velocity times half the mass so 10% less speed gets 19% less kinetic bang. That still leaves a lot
but when you multiply by 10 hits or more it makes a difference. HE shells have both kinetic and explosion.

Roughly by military measure a single 20mm cannon is worth 3 50 cal guns.

BillSwagger
07-27-2009, 06:35 AM
Side by side, one He round will do far more damage than one 50 cal round. You put 8 50 cal beads on a target and its a much different story.

Bird shot is probably not a fair example, but other than slugs there is other ammo, which is essentially 9 large pellets that can be very powerful. When i was a teen, i had the chance to shoot some shotguns. I think because they are buck shot I had the perception that they spread apart or outward from the barrel, which is true, but with in 100 yards those larger pellets are still landing with in a 6 to 12 inch radius, and they inflict large amounts of damage on the target.
I'm no expert on shotguns and i've never shot a slug from one, but the things i've seen buck shot do is still pretty powerful even at longer distances.
In regards to the 50 cal, its probably more like a shredding effect, that has the potential to punch several small holes in a very concentrated area, or even produce an effect similar to a shotgun.


I might agree with the 20mm, in regards to being equal to three 50 cals, but also consider a bullet that never hits its target, is always not effective.
If i can land 50 shots of my M2 guns, and only 6 shots of my 20mm, ....what is more effective?
The late war Hispano ended that question, by increasing the firing time to equal that of the 50 cal.
The 50 cal also made its advancements, with the M3, increasing ROF to 1200 rpm.

M3s were on the P-47Ns, and P-47Ms, in the last months of the war. Thats potentially 160 rounds per second.

M_Gunz
07-27-2009, 08:32 AM
Those 20mm are not much if less RoF than the M2. You want to compare lots of 50 cal to one shell then it should
be 37mm or larger! Consider Spitfire with 2 x 20mm and 2 x 50 cal compares directly to 8 50 cals. FW 190 or
Tempest with 4 x 20mm (plus MG's on the FW) is more. 4 x 50 cal is really plenty as the quad 50 AA gun.

M2 50 cal is a good weapon but it's not the end-all by any means. It did prove to be on the anemic side of the
balance in Korea and was dropped later on. 50 cal range is less than 20mm including bullet travel time to the
longer ranges the 50 cal is effective at. Part of effectiveness is being able to reach the target before it can
dodge fire, that's why the calculated effective range is much less than the can penetrate and damage range.
If the target plane holds steady then massed 50 cal fire is good out past 1000m.

BillSwagger
07-27-2009, 08:25 PM
Originally posted by M_Gunz:
If the target plane holds steady then massed 50 cal fire is good out past 1000m.

Actually I've read effective up to 1800 yards.
This also probably done through a scope and under very controlled conditions.
I'm not sure how they rate "effectiveness", but i'm sure its doing more than just chipping the paint at that distance.

I've also read that effectiveness in an aircraft is much different when you factor the site used and loads on the pilot from turning/rolling.
Other sources downgrade the effective range of the 50 cal down to 400M for this reason, but also mention shots dead ahead on a steady target put the effective range closer to 800M.(from inside a cockpit).

With 20mm it was more like 250M, dead ahead was 600M, but that all changed when they improved the firing times.

Unfortunately, for the late war Hispano, even it suffered from jamming at higher altitudes.
That was the primary difference in use of the F4U-1c and F4U-1D. 1c was a low level ground pounder, while the 1D was a high altitude dog fighter. I've also read that it carried two M3 50 cal, and 4 M2 50 cal, but that was quickly disputed, as someone from this forum told me the M3 was a post ww2 development.
The P-47N had them, so why wouldn't the F4u-1d.

Korea proved to be more successful for the 20mm because they had further developed the firing mechanisms on the gunships.

DKoor
07-27-2009, 08:44 PM
Problem with aerial gunnery is that we have two objects moving and that complicates things a lot.
Sometimes pilot can hit target at 400m with one burst with little lead... another time his projectiles will fall short at that distance with that exact same lead! Not to mention that sometimes when hit with say 20 projectiles, aircraft at 400m will receive one portion of kinetic energy, and on another occasion same distance same quantity of projectiles and basically same hits target aircraft receives less energy or more energy, depending on speed...

Speed of the target is IMHO the biggest factor (among many) that may mess whole thing...

M_Gunz
07-27-2009, 08:44 PM
MG 151/20 has a lower velocity but only a little, high ROF and electric firing mechanism.
The Russian 20mm is high velocity and high ROF as is the Hispano.
The US gun makers just had to screw with the Hispano design and didn't get it straightened out in time.

The larger projectile has less frontal area per mass. It's squares to cubes ratio, you can make a longer
bullet and run it up to higher velocity but in the long run the smaller diameter is range limiting. That's
why the big artillery gets used for counter-battery work and the tanks got bigger and bigger guns.

BillSwagger
07-29-2009, 06:53 AM
i came across a Popular Science magazine from 1944.
They had some odd information in there.
They claim the lethal range of the 50 cal was 800 yards and a pilot with a good shot could down planes at 1000 yards.

It also went into the effectiveness of the armor piercing projectile. Its tough to read because of the pixel size of the article, but it shows a picture of round only denting a plate of armor at 2700 ft per second, and below it a picture of a round puncturing the plate at over 3000 ft per second.