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> Angled Shooting - A theroetical question
Angled Shooting - A theroetical question
@ 06:19 pm (GMT) |
VinceHi All,Don't know why but this question occurred to me the other day so I thought I'd ask. With an extreme angled shot at long range where the difference between the LOS and the TBR is significant I understand that the drop is based on the horizontal distance travelled but how do you calculate the bullet impact speed and wind drift? Is it based on the LOS or the TBR? (I'm assuming LOS). And if the bullet speed is primarily affected by LOS (or time of flight) then this must change bullet drop at a certain point regardless of the horizontal distance travelled. I'm thinking of a situation where you use a rangefinder to get TBR then dial based on a drop chart. Cheers Vince |
Replies
@ 07:21 am (GMT) |
Nathan FosterRe: Angled Shooting - A theroetical questionHi Vince, this is a good point and ties back to the Tactical Tomfoolery article I wrote recently.I don't use the TBR function in the range finder. Most folk will think I am living under a rock but there is a reason why. By having angles on my printed charts, I can use the columns like an abacus for altitude. If I go from sea level to mountain terrain, the 10 degree column becomes my 0 degree elevation column while the 20 degree column is used for 10 degree shots. This is why I include a 30 degree column for long range - even though it is highly unlikely one would ever get a 30 degree long range shot. As an example of a random factory .308 Match load - The difference in wind drift between a 700 yard shot at 0 degrees versus a 700 yard shot at 20 degrees from a .308 is about .2". TOF is 1.0434 versus 1.0439 seconds. As a contrast to this, an onboard TBR calculation will tell you that the range is shorter for the 20 degree shot. For more info on this subject, please see my Long Range Shooting book. I don't mind the range finder providing me with an angle as an extra feature. But that's as far as I like to take it. Hope that helps a bit. All the best. |
@ 03:10 pm (GMT) |
Scott StruifRe: Angled Shooting - A theroetical questionHi. That’s one of those questions you can understand how to address, because you know the effect, or you can understand how to grasp, because you’ve studied the physics. It’s unintuitive to think that a bullet shot uphill doesn’t struggle against gravity to get there. Most explanations offered to shooters for this phenomenon appeal to the shooter to reject his intuition that gravity pulls stronger on an object traveling uphill.You can understand how to counter the effect and properly hold low. But can you resist the urge to hold high in the heat of the moment? While I agree with Nathan that the less gadgetry the better, I’d trust TBR if I had it. |
@ 08:35 pm (GMT) |
Magnus VassbotnRe: Angled Shooting - A theroetical questionHi.The established "rule" that gravity works along the horizontol distance (tbr) is just a simplified way of working around things, that just so happens to work out well enough at medium ranges. But it is incorrect, and starts getting too inaccurate at some point, like the 700 yards Nathan is referring to. The only thing that affects drop, is time of flight. As you are on to. Same goes for wind. When we shoot steeply up or down, we still have the same amount of vertical drop at a given distance, regardless of angle. If we shoot straight up or down 90°, we still have the same drop, even though it appears to be zero relative to line of sight. But the effect of gravity is still the same. I think the main reason for all the confusion and ignorance, even among generally smart people, is that this problem is rooted in a combination of physics (gravity vs time) and geometry (line of sight vs trajectory), and the classic way is to only solve it as a geometrical problem, while trying to explain it as a physical problem, but with the wrong input (tbr instead of tof). |
@ 12:08 pm (GMT) |
William BadgleyRe: Angled Shooting - A theroetical questionTo all of the above. This is why I love this site so much. I always thought TBR was all that was needed. Never gave TOF a thought. But in reading these discussions it has become apparent it's a bit more complicated than we all thought. And now I understand it more fully. Though I rarely shoot beyond 400 yards I still want to have a complete understanding of these things. And it baffles me, with the sophisticated drop chart software we have, that no one has done the calculations to allow for TOF. Hope one of the software programmers are watching this site and take it to heart. Thanks to all of you for your input. |
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