Actually an interesting question (on GE gatling gun)

[AJMD429]

https://www.quora.com/Don-t-the-bullets ... tling-gun?

I know they wouldn't 'spiral' after leaving the barrel, but they ARE getting 'thrown' to the side a bit...

I would expect that (guessing) 3,000 fps, the bullet is in the barrel maybe 1/500th of a second, but if the barrels rotate (guessing) every 1/10th of a second, they'd rotate 1/10th of a circle or 36 degrees in 1/100th of a second, and in 1/500th of a second, about 7 degrees. A muzzle 7 degrees to one side of the breech would throw the round quite a bit to the side (or up, down, whatever the firing-barrel's indexing is).

Is that accounted for in the aiming...? I know they may 'walk to the target' but I'm assuming perhaps the sights for that initial round would be seven degrees off the axis of barrel rotation...???

Anyone actually know...?

[Hawkeye2]

I would think it would be no different from zeroing a vintage 94 with a side mounted scope. The only actual concern is the location of the muzzle at the exact instant the bullet exits. Given the distance between the sights and the muzzle the line of sight and the bullet's path would be converging up to the zero distance and diverging after that, possibly by a significant amount. Not a 100% true statement but close for a flat shooting round. I expect pin-point accuracy isn't needed with this weapon, close enough is OK. Walking to the target works but it wastes a lot of ammo and time, better to have the first burst where it's needed.

[milton]

I can't say for sure about the 30mm GE gun but I do know that the 20mm gun fires its projectiles in a straight line.You do get the normal dispersion of a typical cartridge producing a "group" at various ranges.I got to spend a lot of time on the 20mm version and have seen the weapon fired at 1000 yards with minimal dispersion and the optical sight reticle fixed in the sight center with the attached radar shut down.Just guessing but it appeared that a burst would hit in an area that measured 2 to 3 feet max at 1000 yards.

[Catshooter]

Doc,

It's been years since I read it, but if I recall correctly from ignition to bullet exit for a .45 ball is in the hundred thousandths of a second. Like seven or somethin. Not sure. GI 7.62 is slower than our .308, so probably more like 2,500 fps. Thus angular rotation would be tiny. Or even less. The dwell time difference between the .45 and the 7.62 wouldn't be proportional as the biggest factor would be the primer and powder ignition speed. So that would be nearly identical, I mean your talking microseconds here. The 7.62 147 grains would out-accelerate the 230 .45 of course, but then it has to accelerate to about four times the velocity too.

In addition, since all the bullets are exiting at the same point of rotation all you'd have to do is set the sights to coincide with that point and Bob's Your Uncle. If there is actually any angular velocity given to the bullet (and I suppose there would be, however tiny) all bullets would be given it equally and would run in a straight line (sorta) from there on out.


Cat

[Bronco]

Once the bullet exits the barrel, it moves only tangentially to the rotation of the barrels. The only spin it has is from the rifling.. Think of a circle touching a straight line. The bullet moves along the straight line depending on which way the barrel are rotating. Of course I am not taking into account gravity, loss of velocity and other such phenoms.

[Jay Bird]

Doc...for the ones like me who can't do the math they have this thing called tracers.

Speaking of tracers I pulled a dozen from Vietnam Nam era .308's and loaded them into 300 Blackouts with 6 grains of Unique. They worked great....didn't work the action but they sparkled the night sky.--6

[AJMD429]

Speaking of tracers I pulled a dozen from Vietnam Nam era .308's and loaded them into 300 Blackouts with 6 grains of Unique. They worked great....didn't work the action but they sparkled the night sky.--6

That sounds fun....!

[marlinman93]

Since it wasn't built for long range target shooting, I doubt a little deflection is a concern to anyone shooting it, or on the receiving end of it.

[piller]

Due to the extremely short time any forces imparted by the barrel movement have to act, it is unlikely that barrel movement imparts any noticeable sideways movement to the fired bullet. Just my opinion.

[AJMD429]

Due to the extremely short time any forces imparted by the barrel movement have to act, it is unlikely that barrel movement imparts any noticeable sideways movement to the fired bullet. Just my opinion.

Doing the 'math' ....

"I would expect that (guessing) 3,000 fps, the bullet is in the barrel maybe 1/500th of a second, but if the barrels rotate (guessing) every 1/10th of a second, they'd rotate 1/10th of a circle or 36 degrees in 1/100th of a second, and in 1/500th of a second, about 7 degrees. A muzzle 7 degrees to one side of the breech would throw the round quite a bit to the side (or up, down, whatever the firing-barrel's indexing is). "

...was what made me wonder. It takes 1/500th of a second for a 3000 fps projectile to travel 6 feet (assumed barrel length). If the barrels rotate ten times a second (not sure if that is accurate), then in 1/500th of a second, the barrel will rotate 10x360 degrees/500 - or about 3600/500 degrees, or 7 degrees. If the diameter of the assembly is 1 foot (again, I'm unsure, but that seems reasonable), you would have at least a couple inches of movement.

A couple inches at six feet (again, an assumption), would 'toss' the bullet two or three feet at 100 yards, or at the more typical 'gatling gun' ranges of 500 yards, TEN FEET or so....!

So...I'm assuming the sighting apparatus takes this into account.

Just curious.....

(I don't own a 20mm gatling gun, or even a 308 one - but it is an interesting issue involving physics and ballistics....)

[piller]

The movement at the instant the bullet leaves the barrel is what will have the effect.