Long Range Shooting and TBR

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Originally Posted by andyanimal31

Its gravity that is the effect tbr is compensating for not pushing through the air

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Its the same thing, without gravity pushing through air is effortless.

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Originally Posted by andyanimal31

To be fair that if you don't under stand whats been talked about you shouldn't be shooting past 450m at the most.
I would go as far to say there is a hell of a lot of people taking shots at animals and can't work out why they are missing or fluke a good shot every now and again.
Yes I do know what I am talking about.

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See quite a bit of that on youtube. Long range. Clean misses.

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Greetings All,
So to summarise, the use of true ballistic range to calculate drop allows for all of the drop due to gravity and most of the drop due to velocity loss What it does not allow for is the additional velocity loss due to the difference between TBR and line of sight range (the actual distance to the animal). This becomes significant as inclination and range increase and as ballistic coefficient decreases. The consensus also seems to be that this becomes important somewhere beyond 400 metres. From Tui4Me,s example above the error is around 0.5 MoA at 650yards (600 metres). Hard to hold that close in field conditions. Significant as this may be it seems small potatoes compared to allowing for wind deflection at these ranges. Something to think about.
Regards Grandpamac.

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Originally Posted by Mauser308

The interesting bit is this is just one small sector of the LR art form.

Once you add in denisty/pressure variations, wind/air movement, sun position, and the biggie (elephant in the room) pockets of humidity in the path of where you are shooting TBR and angle errors are only a part of the fun. I've been in the butts on a day when fog blew in and while the range was still open as the fog settled (prior to RO calling it through lack of vis) we noted the hits from the good shooters that we were consistently indicating suddenly became misses or edgers and the poor shooters started to really give us the shits with stuff impacting at just over head in the butts. Not exciting at all...

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Greetings Mauser308,
And target shooting is on a dead level range with targets at exact ranges. Plus you get sighters to correct for conditions. Went out with my son when he was shooting FTR at 1,000 yards one day. Boy those jokers can shoot. No targets as such you see where your shots go on your cell phone. Hard to see how that level of precision can reliably be achieved in field conditions with all the things you mention plus more. The lack of sighters would be critical.
Regards Grandpamac.

Spent this past weekend participating in a extra long range event on a central north island station.

After speaking to several of the other competitors, and doing some testing, I am starting to think @Tui4Me is onto something here.

I was also not correct in saying the flight time (in the software) for the 2 scenarios would be similar.

Taking the 1000m / 20 degree angle

940 @ 0 : 1.522 sec
1000 @ 20 : 1.622 sec

this is for something leaving the muzzle at 875 m/s, so it does make sense.

The actual flight time will be the longer value, gravity only works on the short leg of the triangle. Because the solver is time-of-flight based, you will get a more accurate value by entering the true LOS value and angle, as opposed to just the TBR value.

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Originally Posted by ebf

Both the examples you have above show an error of less than 1 MOA.

It just illustrates the problem with ethical hunting at extended ranges...

Let's be honest, most guys with their hunting rigs struggle to hit a 2 MOA plate beyond 400 yds

A solid kill zone on a deer to me is about a 300mm diameter circle. Then work it backwards, if you can truthfully hit a 2.5 MOA sized target repeatedly and consistently (under stress and time pressure), then the max distance you should really be looking at hunting is around 450yds.

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300mm may be ok for big reds but on small fallow the lethal zone reduces to half that and it gets pretty tricky over 200m.

Lets put this to bed guys..

1. "First, the range scaling ignores the effect of the bullet slowing down as it travels thru all the air between the shooter and the target." - Bryan Litz

2. Second, range scaling ignores the effect of the gravity that's either acting to decrease or maintain the bullets speed." - Bryan Litz

3. In addition range scaling does not distinguish between uphill and downhill shooting" - Bryan Litz.

@Tui4Me, where are those Litz quotes from pls.

Interested to read more about his comments of differences between uphill/downhill.

It all depends on what "good enough" needs to be. I always input range and angle separately other wise the calculator doesn't know if it needs a wind value for 550m or 600m. The real world difference in shooting 30deg up vs 30deg down is next to nothing in a distance thats achievable. Ie where do you plan to shoot over 1000m at a 30deg down slope. We shoot some decent angles down here but thats never going to happen.

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Originally Posted by ebf

@Tui4Me, where are those Litz quotes from pls.

Interested to read more about his comments of differences between uphill/downhill.

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At a guess shooting downhill the bullet stays faster for longer. Uphill slows down quicker due to gravity. The longer or shorter its flying will move it further along its curve (or not)

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I disagree Ned, a bullet it's the true distance in a horizontal line that counts it's immaterial if that's angled up hill or downhill. Gravity is a constant.

NED is correct.

"A bullet always shoots slightly higher when it is fired downhill than when it is fired uphill at the same angle. The reason for this is that when the bullet travels upward, there is a component of gravity acting as drag on the bullet that increases the drop slightly.
When the bullet travels downward, on the other hand, there is a component of gravity acting as drag on the bullet that decreases the drop slightly."
Sierrabullets
https://www.sierrabullets.com/exteri...l-or-downhill/

I stand correcited however a theoretical 2/10 of an inch difference in drop at 500 yards between going uphill or down hill doesn't make any difference to your point of aim in practical terms.

Good find. All I found on my google search was some stuff on bowhunting and shooting up v downhill. A lot more relevant for them than to us throwing lead around. (i.e. the example I saw was a whole yard of elevation difference over 60 yards between up and downhill. Can't remember the angle)

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Originally Posted by ebf

@Tui4Me, where are those Litz quotes from pls.

Interested to read more about his comments of differences between uphill/downhill.

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Chapter 4 of Bryan Litz book Applied Ballistics for Long Range Shooting.

Its all makes sense to me now, thanks for the insights

Remember these?
And then use your cosine and los.
Can't fuck it up thenhttps://uploads.tapatalk-cdn.com/202...e2ef04f65a.jpg

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Originally Posted by ebf

@Tui4Me, where are those Litz quotes from pls.

Interested to read more about his comments of differences between uphill/downhill.

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You need this !https://uploads.tapatalk-cdn.com/202...a36afa3915.jpg

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