Ballistics help

[gramps73]

I got a new CDS scope and wondering if there’s anyone that could help a guy out with getting the ballistic coefficient through a chronograph for his rifle.

7Mm mag

In or around the Calgary area.

Thank you.

[Homesteader]

https://www.hornady.com/team-hornady...alculators/#!/

Would this work?

Oops, sorry you want to shoot through someone's chrony, Cowtown is too far south for me. Good luck

[birdseye]

Sorry to far away to help get your load info

[Alberta Bigbore]

If ur up my way i have a Magneto V3

[6.5 shooter]

Zero in at "exactly" 100 yards then without moving the turrets (reticule) shoot at 200 yards with the same hold on target, then 300 then.... Measure the actual bullet drop on the targets, presto instant poor mans chrono.

[markg]

Originally Posted by gramps73

I got a new CDS scope and wondering if there’s anyone that could help a guy out with getting the ballistic coefficient through a chronograph for his rifle.

7Mm mag

In or around the Calgary area.

Thank you.

What bullet are you using? Most manufacters post the BC online. If your looking for velocity data then you absolutely need the chronograph. I can help you but not until the end of November unfortunately.

If you need it sooner you could pick up a magneto speed sporter

https://www.westernmetal.ca/product/...h-kit-a-ms-sp/

or a used one from the forum

http://www.outdoorsmenforum.ca/showthread.php?t=433765

[fps plus]

[QUOTE=6.5 shooter;4759401]Zero in at "exactly" 100 yards then without moving the turrets (reticule) shoot at 200 yards with the same hold on target, then 300 then.... Measure the actual bullet drop on the targets, presto instant poor mans chrono.[/QUOTE

One more number needed .

Close but not quite. Need one more number and that would be exact B.C
If you had chronograph for velocity and exact bullet drop as you say you can calculate exact BC

[elkhunter11]

Originally Posted by 6.5 shooter

Zero in at "exactly" 100 yards then without moving the turrets (reticule) shoot at 200 yards with the same hold on target, then 300 then.... Measure the actual bullet drop on the targets, presto instant poor mans chrono.

And if you shoot the load as far as you would shoot at a game animal, then you don't need to know the B.C. , or the velocity, because you already know the drop as far as you will shoot. And I for one shoot my loads to verify the calculated trajectory. I only do the calculations to make sure that the point of impact will be on my target.

[Subaru297]

Unless you need the exact number for a specific purpose you can calculate the velocity with fairly good accuracy using a ballistic app.

Put all your info into the ballistic app including the manufacturers advertised BC or see if there is a Brian Litz published BC and use that.
Put in your best guess for velocity based on the reloading manual or factory box estimate.
Zero your rifle.
Then fire a group at a known distance (the further the better).
Use the ballistic app to determine your scope adjustment.
For example 4.5 MOA at 300 yards.
Shoot a group at 300 yards and measure how far above or below point of aim you are.
Lets say you are 3" low at 300 yards so you needed to use 5.5 MOA for your scope adjustment. Shoot another group to confirm your adjustment was correct.

Some ballistic apps will have a truing function. Strelok does, Chairgun probably, and Geoballistics does.
Put in your distance and corrected scope adjustment of 5.5 MOA and the app will calculate the muzzle velocity. Then click the use this velocity button.

What ballistics app are you using? I'm sure someone here can tell you exactly how to do it.

Cheers

[gramps73]

Can you recommend a good ballistic app?

[Subaru297]

GeoBallistics is the nicest one I have found since Strelok got removed from the Google Play store. They both have the truing function. GeoBallistics is free to try for a single rifle and load but if you want to add multiple rifles then you need to pay for it.

Chairgun is a clone of Strelok and would be a good one to try but I hate subscriptions so I bought GeoBallistics instead.

[gramps73]

Originally Posted by Subaru297

GeoBallistics is the nicest one I have found since Strelok got removed from the Google Play store. They both have the truing function. GeoBallistics is free to try for a single rifle and load but if you want to add multiple rifles then you need to pay for it.

Chairgun is a clone of Strelok and would be a good one to try but I hate subscriptions so I bought GeoBallistics instead.

Thank you will give them a try

[6.5 shooter]

[QUOTE=fps plus;4759412]

Originally Posted by 6.5 shooter

Zero in at "exactly" 100 yards then without moving the turrets (reticule) shoot at 200 yards with the same hold on target, then 300 then.... Measure the actual bullet drop on the targets, presto instant poor mans chrono.[/QUOTE

One more number needed .

Close but not quite. Need one more number and that would be exact B.C
If you had chronograph for velocity and exact bullet drop as you say you can calculate exact BC

Not exactly, but you can reverse engineer the drop chart in a good ballistics calculator and come up with the overall speed of your bullet then you can figure out the B.C. from there. Nosler, Speer and Hornady have a ton of drop charts. Takes some work and not exact science but it works.
Or spend $800 bucks on a Garmin and be sure

[fps plus]

[QUOTE=6.5 shooter;4759965]

Originally Posted by fps plus

Not exactly, but you can reverse engineer the drop chart in a good ballistics calculator and come up with the overall speed of your bullet then you can figure out the B.C. from there. Nosler, Speer and Hornady have a ton of drop charts. Takes some work and not exact science but it works.
Or spend $800 bucks on a Garmin and be sure

I understand what you are driving at but you need the velocity to calculate to use the chart for BC

If I run a bullet with a lower Bc at a higher velocity than a bullet with a high BC at a lower velocity they can have similar bullet drop .

They don’t have the same B.C