The Effect a Raindrop Has On a Bullet

[mfb]

mfb- I don't see how the distribution approach will work, hitting the water is not binary, some bullets may glance a droplet and be slightly deflected, and those glancing bullets will form a distribution with an intermediate half-width.

They are all part of the broader distribution. That is the reason why this is a broad distribution - the details of the impact vary.

 

[A.T.]

This would be an awesome Mythbuster's episode. Especially with the high speed camera.

In the below video at 2:00 the bullet collides with some white balls, which disintegrate like a fluid, but seem solid before impact. They move faster than the bullet. What could that be? Lead?

https://www.youtube.com/watch?v=QfDoQwIAaXg

 

[mikeph]

They are all part of the broader distribution. That is the reason why this is a broad distribution - the details of the impact vary.

Gotcha, I think my brain stopped working when I wrote that.

 

[Andrew Mason]

In the below video at 2:00 the bullet collides with some white balls, which disintegrate like a fluid, but seem solid before impact. They move faster than the bullet. What could that be? Lead?

It is likely bullet lead (an alloy containing trace elements of antimony and other metals). The high speed impact creates an enormous pressure within both bodies. Since this pressure deforms the metal bodies, they heat up (think of the pressure multiplied by the volume change as energy added to the body). When they heat up enough, the metal melts and, because of the pressure, explodes into tiny fragments.

AM

 

[Win_94]

Here are the results from the second test.



Specifics:
Howa 1500 30-06
Hornady 150gr FMJ, 2600fps
Varget 46.6gr
CCI 200
Winchester case
300 yards
Dropper devise 260 yards from target

Shots 3, 4, 5, 6, 8, and 9; hit water drops. They make an 8 inch group.
Shots 1, 2, 7, and 10; did not hit drops. They make a 1.5 inch group.
The group that hit water drops, is over 5 times the size of the group that didn't.

Note:
I thought shot 8 missed a drop, otherwise I would have taken shot 9 without water as I did shot 10. I couldn't see the water hits on the camera so I speculated from the POIs on how many hits on drops I had accomplished.

I think it is obvious that a raindrop can affect a bullets trajectory.

 

[mfb]

Thanks for the test. The result looks very nice.

 

[Win_94]

Thanks for the test. The result looks very nice.

You're welcome! I'm glad now that I did another test; it was much better the second time around.

 

[mikeph]

I'm convinced! I wonder why most of the hit bullets end up higher on the target. Must be a random fluke, hitting water droplets on the top half more than the bottom? I'd expect the hits would end up lower if they lose speed during the collision.

 

[Win_94]

I'm convinced! I wonder why most of the hit bullets end up higher on the target. Must be a random fluke, hitting water droplets on the top half more than the bottom? I'd expect the hits would end up lower if they lose speed during the collision.

I think it is a random fluke. The other test has one low hit, then the first video has a 2 low hits if you consider I aimed high on the second shot. But yes, it is odd there weren't as many low shots or more.