Knowing velocity/energy down range?

DGY

DGY

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Good day, I can find out energy at the muzzle(ish) with my velocity from my chronograph, but how one find out the velocity at different distances, like 100-200-300 metres?
 
You could use ballistic tables, if you trust the B.C. number from the bullet maker. (I see Sierra V manual lists up to four different B.C. number for some of their bullets - depending on the velocity range) You could also shoot (hopefully not hit chronograph) at those ranges?
 
Fancy expensive way: use a fancy $50k bullet tracking radar
Fancy expensive way: use a fancy $1k electronic target like the F-class guys use
low tech way: use a ballistic calculator, as they will calculate your velocity at each distance
 
The shotmarker targets are really nice for giving g you stuff like your velocity at the target , but you bullet has to be supersonic in order to trigger it.
Plus, you need to be able to store your frames on-site or build a knockdown style frame.
One of our members has one and we just move it to the side when it is not being used, we have three more coming as well.
A chronograph and ballistic calculator works for determining average velocity as well. But I shoot loads at various distances because I am more concerned with accuracy rather than exact velocities
Cat
 
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DGY said:
Good day, I can find out energy at the muzzle(ish) with my velocity from my chronograph, but how one find out the velocity at different distances, like 100-200-300 metres?
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Chronies like my Labrador will give you multiple MV readings over various distances. Couple this with drop date form actual long range shooting and a ballistics calculator that you sync with real world results and you get a very good idea of MV and energy at various distance. These combinations are key to developing a solid dope card.
 
Just set your crony at the 200 and 300 yard mark. Take three shots and then walk/drive down to the desired distances and check on the velocities. You will receive the exact velocity instead of an estimate by using a math table.
 
6MT said:
Doesn't a LabRadar do that? I know mine shows velocities at different ranges. I'm not sure about energy.

Not being a hunter, the only thing that matters to me is velocity at the muzzle.
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I do not know if a LabRadar does that or not - but if you have the velocity and the bullet weight, you have the energy also, with a little bit of math ...
 
6MT said:
Yeah, the LabRadar does give velocities downrange. I don't really pay attention to it though. So I don't know about whether it shows energy as well.

EDIT: I do sometimes look at sub-sonic transition distances on the LabRadar. Because certain bullets' accuracy will change as they transition below the speed of sound. And sometimes it is nice to know the distance when that happens.
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If you know the velocity and bullet weight , energy is a math equation. - dan
 
I found a ballistics calculator is very accurate when calculating bullet trajectory. I there for have to assume that the velocities stated have to be quite accurate.
 
Got to SAAMI.ORG website - this formula is from there: E= energy in foot pounds:

E=(W*V2)/(14000*gc).

In this formula, W = weight of projectile, in grains; V = velocity, in feet per second; gc= gravitational constant, 32.174 ft/s2

To clarify that font - I believe that should be V squared - not Vx2 - so in first brackets should be (W x V x V)
 
A Labradar will give you velocity tracking down range. But it is limited to somewhere around 100m. I'm pretty confident it won't track your bullet to 300m. That's where they upsell you on the $50k version.
 
Thanks every one, I won’t shoot at my chrony at 200m lol… I do t own a labradar!
I was hoping to find a link to a table that would give me the info!
 
track said:
Just set your crony at the 200 and 300 yard mark. Take three shots and then walk/drive down to the desired distances and check on the velocities. You will receive the exact velocity instead of an estimate by using a math table.
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Interesting, how many guys will hit the chrony
 
DGY said:
Thanks every one, I won’t shoot at my chrony at 200m lol… I do t own a labradar!
I was hoping to find a link to a table that would give me the info!
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I can not help about a link - but I am sure there is one on-line. I use the ballistic tables from the Nosler #7 manual - Nosler #9 does not have them any more. You would need to know the G1 Ballistic Co-efficient (B.C.) - as claimed by the bullet maker - does not have to be by Nosler - and a muzzle velocity - then the table give you speeds by 100 yard increments out to 600 yards.
 
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