Question

[Nath-BDP]

Why does the Hispano disperse less than the Mauser MG 151/20 ?

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Nath_____
9./JG 54 "Grünherz"
 

"It felt as if an angel was pushing..."
-Reponse of Gen. Adolf Galland after flying the fourth prototype Me 262 in May 1943.

[This message has been edited by Nath-BDP (edited 11-28-2000).]

[Karnak]

Higher muzzle velocity.

Sisu
-Karnak

[funked]

I got the impression that the Mausers had less dispersion than the Hispanos.  I haven't done anything vaguely resembling a scientific test though.

[Nath-BDP]

umm go fire front cannon in 38 then do 109.

[Dinger]

Try these:
Mauser has lower muzzle velocity and lower shell weight.  The mauser HE shell most commonly used in WWII had a flat tip for better fuzing, so the projectile shape is less aerodynamic too.

But we really should figure out a dispersion test of some sort before jumping to conclusions.  And remember, they will be fiddling with the dispersion pattern in 1.05, so perhaps we should postpone any such tests.
Just firing p38 and 109 guns on the ground isn't gonna work, because the p38's tricycle gear will make the HS trajectory appear flatter than the 109's taildragging configuration; moreover the lower muzzle velocity and higher drop-off rate of hte mauser will be accentuated by the slight upward firing from on the ground.
That make any sense?

[Andy Bush]

Muzzle velocity is not a primary determinant of dispersion. It has a direct influence on gravity drop when used in a fixed firing distance (high muzzle velocity means = less TOF = less gravity drop), but this is not dispersion.

Dispersion is a factor of projectile aerodynamics and ballistics, barrel stiffness, barrel length, and barrel wear.

As to which round had the least dispersion, your guess is as good as mine!

Andy

[Maverick]

 

Originally posted by Andy Bush:
Muzzle velocity is not a primary determinant of dispersion. It has a direct influence on gravity drop when used in a fixed firing distance (high muzzle velocity means = less TOF = less gravity drop), but this is not dispersion.

Dispersion is a factor of projectile aerodynamics and ballistics, barrel stiffness, barrel length, and barrel wear.

As to which round had the least dispersion, your guess is as good as mine!

Andy

Andy,

You missed another angle. Ammunition for full auto weapons is typically loaded to create a dispersion. What the designers and ammo people are looking for is not a stream of rounds flying in the same track to the same point of impact. MG ammo and light cannon ammo is set so that there is a pattern similar to a shotgun (albit a very small cone) cone of projectiles. This leads to a circular or elliptical beaten zone where the rounds land. Fully auto weapons aren't set or loaded with a "laser" accuracy in mind. This is often aided by the movement of the weapon itself during firing as it doesn't drop back into battery or position in exactly the same place it was at the start of firing.

Before someone flames me about the "cone" being similar to a shot gun, the cone is much less dispersed than the non ballistically designed round balls from a shotgun shell. The "mental" image is the same as the shells do disperse as a cone on firing.  The elliptical shape is from the cone striking the ground downrange. The pattern of impacts spreads in a longitudinal manner as they impact.

Mav

[Andy Bush]

Mav

Good words!

Your point about gun vibration is especially notable. We used to fire the Vulcan 20mm in an external gun pod in the F-4...talk about dispersion!! It was a great area denial weapon, but when shooting for score on the gunnery range, it left a lot to be desired!

Now, the A-10 was a world of difference. The GAU-8 has a nice, tight pattern...much better than any 20mm I've fired. Of course, having the jet built around the gun helps! And the 20mm now with the PGU-28 round is much improved.

Andy

[Jigster]

.50 M2 Brownings sprayed like a shotgun on standard mounts. No exageration intended  

[Toad]

Stop hi-jacking this thread with rational discussion about dispersion!

We need to get to the bottom of the anti-LW/pro-Allied conspiracy!