Max peak elevation of trajectory?

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GSells
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Max peak elevation of trajectory?

#1 Postby GSells » Sun Aug 05, 2018 5:04 pm

Hi all , I’m just wandering if someone smarter than me could help ?
If I had 30 meters correction above the target, what would be the peak height of the projectile during its flight ? Would it be more or less than than the elevation correction? Regards Graham :D

Tiger
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Location: Canberra ACT

Re: Max peak elevation of trajectory?

#2 Postby Tiger » Sun Aug 05, 2018 6:34 pm

The first question I had was at what distance?

And most importantly 30 Meters or 30 minutes?

1moa at 900m is roughly 260mm I think, so we are talking very different scenarios.

Dave G

bruce moulds
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Re: Max peak elevation of trajectory?

#3 Postby bruce moulds » Sun Aug 05, 2018 7:28 pm

a 540 gn long range profile black powder bullet at about 1300 fps goes about 50 feet high at max height of trajectory.
this is way above the flags.
modern smokeless vld bullets go nowhere that.
keep safe,
bruce.
"SUCH IS LIFE" Edward Kelly 11 nov 1880
http://youtu.be/YRaRCCZjdTM

GSells
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Re: Max peak elevation of trajectory?

#4 Postby GSells » Sun Aug 05, 2018 8:47 pm

Tiger wrote:The first question I had was at what distance?

And most importantly 30 Meters or 30 minutes?

1moa at 900m is roughly 260mm I think, so we are talking very different scenarios.

Dave G

17.5 miliradians or about 67.5 moa at 1 mile or 1.6 km .
I'm worried about hitting power lines !
Ok , ok I will come clean !
https://youtu.be/wBtDtb2n7bs

Look at the power lines in the vid ! Would I be close ?

bsouthernau
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Re: Max peak elevation of trajectory?

#5 Postby bsouthernau » Mon Aug 06, 2018 9:21 am

Not entirely sure you've given us enough information Graham but it looks to me that if you're hitting the target at a mile with 67 minutes of elevation top of the trajectory will be around 1050 yards at a height around 38 feet. I did this calculation assuming a .30 cal 210gr sierra.

Happy to be corrected if I've got this wrong.

Barry

GSells
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Re: Max peak elevation of trajectory?

#6 Postby GSells » Mon Aug 06, 2018 10:51 am

bsouthernau wrote:Not entirely sure you've given us enough information Graham but it looks to me that if you're hitting the target at a mile with 67 minutes of elevation top of the trajectory will be around 1050 yards at a height around 38 feet. I did this calculation assuming a .30 cal 210gr sierra.

Happy to be corrected if I've got this wrong.

Barry

Hi Barry , I really appreciate your thoughts! Sorry .338 300 gr Berger hybrid I think a g 7 of .408 ? At 2750 FPS at 20 deg c and 1019 ha at 350 m above see level. The power lines are about 4-500 m part of the flight of 1.6 km . Kind regards Graham.

bsouthernau
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Re: Max peak elevation of trajectory?

#7 Postby bsouthernau » Mon Aug 06, 2018 11:28 am

Litz's book gives that one a G7 of .418 and without taking the atmospheric data into consideration his software says around 25 feet at 500 yards. Happy shooting.

GSells
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Re: Max peak elevation of trajectory?

#8 Postby GSells » Mon Aug 06, 2018 11:39 am

bsouthernau wrote:Litz's book gives that one a G7 of .418 and without taking the atmospheric data into consideration his software says around 25 feet at 500 yards. Happy shooting.

Thanks Barry , looks like we are a long way off the lines , that’s only about 7 m high at that point ! Yes you would be correct with the bc . Was just thinking of the top of my head .

But main thing is , that is safe to have fun and to also protect the sport . Again thank you Barry !

GSells
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Re: Max peak elevation of trajectory?

#9 Postby GSells » Mon Aug 06, 2018 11:54 am

Anyway , that out of the way now , checkout the U tube vid in the link above ! My mate thought it would be cool to get some drone footage of the attempt . I thought it would be a waste of time lol! But wow I’m glad he had it as the mirage was so bad . The only way we could call the corrections was with the drone . As my other spotter through a spotting scope was calling hi and drone spotter calling low ! But they both agreed on the wind which was very helpful!
But we lost a few shots due to that confusion with the mirage !
11 cases in my box! Few were fowlers the day before, 3 were fowlers at that distance at another target with no return info ,( which is 1575m, the fence stopped us going back to make 1600m but close enough!)
Was 3 sighters and one hit before the drone battery went bingo on us !
Again watch the footage My team Darryl and Terry did a wonderful job filming and editing it !

Thanks heaps to my spotters , was a team effort
E44AEAB2-2491-4C15-80DD-12897B7CF511.jpeg

As per usual, click on image to get correct aspects! The yellow shadow is the 32” by 32” gong .
Regards Graham.
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GSells
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Re: Max peak elevation of trajectory?

#10 Postby GSells » Mon Aug 06, 2018 11:59 am

Ps , if u look at the left bottom corner of the ground near the gong , you will see a small puff of dust . Which indicates the last terminal trajectory off the gong !

Thanks everyone!

Sorry just edited , it is the other left for the puff of dust not right ! Lol!

GSells
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Re: Max peak elevation of trajectory?

#11 Postby GSells » Wed Aug 29, 2018 11:12 am

bsouthernau wrote:Litz's book gives that one a G7 of .418 and without taking the atmospheric data into consideration his software says around 25 feet at 500 yards. Happy shooting.

Hi Barry , thanks heaps for your help . I’ve been watching Mark and Sam after work ,https://youtu.be/GP6uV9vacaw where they pushed a 7mm rem mag 180 hybrids at 2100 m plus ! Waaay past sub sonic speeds ! 5 second flight time as well ! To me I would previously think this was impossible!!

But On my year off from f class , it has given me a chance to achieve a long time goal of the 1 Mile shot ! Now Barry , this is where I need your help again . We are going to have a crack at 1.9 km with the above load . And I really need to make sure that we are safe . The Transmission wires will be at 800 m now . What will our height be now ? Regards Graham .

Ps .Wires are about 90 feet of the ground .

AlexE
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Re: Max peak elevation of trajectory?

#12 Postby AlexE » Wed Aug 29, 2018 4:52 pm

GSells wrote:
bsouthernau wrote:Litz's book gives that one a G7 of .418 and without taking the atmospheric data into consideration his software says around 25 feet at 500 yards. Happy shooting.

Hi Barry , thanks heaps for your help . I’ve been watching Mark and Sam after work ,https://youtu.be/GP6uV9vacaw where they pushed a 7mm rem mag 180 hybrids at 2100 m plus ! Waaay past sub sonic speeds ! 5 second flight time as well ! To me I would previously think this was impossible!!

But On my year off from f class , it has given me a chance to achieve a long time goal of the 1 Mile shot ! Now Barry , this is where I need your help again . We are going to have a crack at 1.9 km with the above load . And I really need to make sure that we are safe . The Transmission wires will be at 800 m now . What will our height be now ? Regards Graham .

Ps .Wires are about 90 feet of the ground .


Based on the velocity you've given, and Litz' g7 BC for the 300 hybrid, Applied Ballistics says your elevation at 800m would be 16.25m.

Hope that helps,

Alex

GSells
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Re: Max peak elevation of trajectory?

#13 Postby GSells » Wed Aug 29, 2018 8:01 pm

552F1766-87AD-4815-AABA-F43BE3F42189.png


Thanks Alex ,maybe in vain . I’m just looking at JBM and the elevation correction is 26.78 miliradians. Max dial up on my Gun is 13 mils !! So I have to make up nearly 14 mils in my recticle !! I don’t think it’s possible!!
It’s a vortex pst second focal plane and bottom of post is 8 mils , still 6 mils short ! Total elevation correction is 50.882 m above the target! I would have to modify my pseco rifle to do it ! Don’t think I’m willing to do that !

But Mark and Sam make it look easy and I guess they have been doing for a long time and have their gear setup for it !
https://youtu.be/Vjp7SdjMZGA

But thanks Alex , I have litz’s program from one of his first books I’ll check it out there . I’ll be well under the wires if that’s so . But I will confirm again with his above program . :D
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GSells
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Re: Max peak elevation of trajectory?

#14 Postby GSells » Wed Aug 29, 2018 8:12 pm

Even another 20 moa on the rail so it’s 40 moa would only yield 18.19 mils . Then aiming at top of post on 20 x I would still be nearly a whole mil short !! So on my .338 rifle I’ll say it is almost impossible to get to 1.9 km !

GSells
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Re: Max peak elevation of trajectory?

#15 Postby GSells » Wed Aug 29, 2018 8:37 pm

Ok I can get 11 mills out of the vortex recticle , so 24 mills max !! Which is 1.8 km total on about 18 power on the scope ! So it will be a tough shot !! Not to mention even spin drift and Coriolis force !
Wish me luck lol!
8048B617-8783-4320-AD10-38CFD20D1093.png
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