Bullet Drop (of a different kind)

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Re: Bullet Drop (of a different kind)

Post by Archie » 13 Mar 2018, 7:49 pm

sungazer wrote:OB you are correct it is all about the weight of the projectile. They all fall at the same speed it is the weight that determines the energy that is imparted on hitting the ground / head , building ect.


I am being a bit nitpicky here, and I could be wrong, but... not every projectile falls at the same speed (and I’m not talking because of different drag coefficients). Every projectile, ignoring drag and reaching terminal velocity, falls at the same speed only if it starts falling from the same height - because the constant is the rate of acceleration at 9.8m/s

The reason I mention it is because, I do not know but I would guess, if you shoot a 30-06 straight up into the air I’m betting it goes a lot higher than a .22. So when it reaches the top of its arc, it has more time to accelerate because it’s falling a longer distance. Which would mean it’s also going faster when it hits the dirt (or your head) - although I’m guessing it would probably reach its terminal velocity and stop accelerating before then.
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Re: Bullet Drop (of a different kind)

Post by Oldbloke » 13 Mar 2018, 8:29 pm

"although I’m guessing it would probably reach its terminal velocity and stop accelerating before then."

I think that's close to the mark. But both the heavy 30-06 projectile and the lighter 22 projectile would have a slightly different terminal velocity too.
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Re: Bullet Drop (of a different kind)

Post by sungazer » 13 Mar 2018, 9:31 pm

Terminal velocity is reached from falling at not such high height a human body spread eagle is said to reach it falling from only 1500 ft. So pretty much all bullets will reach it on the way down. There is very little difference in the terminal velocity of objects due to size unless you go to the feather and ball sinker extremes. a marble and a cannon ball would fall at almost if not the same speed. The cannon ball would impart more energy when it stops due to its mass.
A 303 takes about 50 seconds return flight 19 seconds up and 36 seconds to come down. Its all covered in detail in the book I mentioned.
If people are after a copy of the book I have it in pdf format and may be able to email it to you or put it on the web for you to download.
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Re: Bullet Drop (of a different kind)

Post by Oldbloke » 14 Mar 2018, 12:25 am

Whikipedea says about 300fps.
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Re: Bullet Drop (of a different kind)

Post by Daddybang » 14 Mar 2018, 7:10 am

Oldbloke wrote:Yeah, that's it, terminal velocity is not that high. But heavier bullets at a given velocity have greater energy and there for more dangerous. The small stuff like. 22 & smaller are unlikely to do a lot of damage. A 180gr would be a problem.


Yep think about hail..a small pea size piece will sting a golf.ball size piece can kill. :thumbsup: :drinks:
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Re: Bullet Drop (of a different kind)

Post by sungazer » 14 Mar 2018, 7:21 am

What I meant OB was it doesnt take much of a rifle to shoot a bullet up 1500 ft in the air. If you can do this it will achieve terminal velocity on the way down and all of them will be pretty much the same speed (300fps) give or take on their drag.
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Re: Bullet Drop (of a different kind)

Post by Oldbloke » 14 Mar 2018, 8:23 am

"Yep think about hail..a small pea size piece will sting a golf.ball size piece can kill. :thumbsup: :drinks:"

That's it.
Hunt safe, look after the bush & plug more pests. :thumbsup: Better to load on the mild side. :o The greatest invention in the history of man is beer. :drinks: "Often the written message doesn't convey all of the information"
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Re: Bullet Drop (of a different kind)

Post by Archie » 14 Mar 2018, 8:26 am

sungazer wrote:What I meant OB was it doesnt take much of a rifle to shoot a bullet up 1500 ft in the air. If you can do this it will achieve terminal velocity on the way down and all of them will be pretty much the same speed (300fps) give or take on their drag.


Ah right. Yep fair point, I misunderstood.

All the maths aside though - I've had birdshot land on my hat and it was more weird than anything, but I have zero desire to have that experience repeated with 7.62x39 at a wedding in Nowhereistan. Even if it should be fine... nah.
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Re: Bullet Drop (of a different kind)

Post by sungazer » 14 Mar 2018, 8:38 am

i doubt you would notice the difference between a 7.62*39 and a 7.62*51 :lol:
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Re: Bullet Drop (of a different kind)

Post by Oldbloke » 14 Mar 2018, 9:20 am

"I've had birdshot land on my hat and it was more weird than anything"

Happens all the time duck opening. Not a problem.
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Re: Bullet Drop (of a different kind)

Post by Hangfire » 14 Mar 2018, 12:01 pm

Gaznazdiak wrote:I remember a very convincing demonstration of area fire by an M60 mounted on a C2 Sight at Singleton in the 70's.
Using map coordinates they slaughtered an acre of innocent balloons from the other side of a large hill.
Can't remember the max effective range for the 60 used this way but my aging memory suggests it was 8 miles.


Only around 2 to 2.5 from memory of my support course 12 years ago and the bellets are coming like rain at that range beaten zone is only 50 odd meters long less even i think. Thats 7.62 in a mag 58. M60 is just less relaible version. The DFSW also use 50 cal mgs now and 40mm auto grenage launchers
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