Muzzle velocity calculation makes no sense.

[guitarpreston]

I just did some trading and came out with a Bergara wilderness ridge SP (18 inch barrel) in 6.5 Creedmoor. I do not have a chronograph so I zeroed at 100 and shot at 200 to measure drop to calculate my muzzle velocity...I have used the Hornady app, ballistics arc, and jbmballistics.com and plugged in the info for elevation, ammo (143 gr precision hunter), and anything else I could and manipulated the muzzle velocity value to make the drop at 200 right...To get the drop of about 2.75 inches its showing the muzzle velocity would have to be 2950-3k fps which seems improbable. Any idea what's going on here? I would have guessed the velocity to be 2500ish based on barrel length.

 

[_Windrider_]

Why are you trying to match drop and not dope? Is it asolute drop or the drop below line of sight?

to be honest, you need to true velocity at at least 600 and make 2-6 match your actual drop (in Mils or MOA…not inches)

 

[guitarpreston]

Im probably using the wrong verbiage and I don't have really any experience doing this.

 

[_Windrider_]

So you need to gather your data on the rifle out to distance.

200 yds .7 mils
300 yds 1.5
400 yds 2.0
500 yds 3.1
Etc etc etc

Then you make the computer match this by tweaking MV at around 600 and BC as far out as you can get and as close to transonic as possible but no less than 800 yds. The number in the velocity slot doesn’t matter, unless it’s 100’s of feet off. For 6.5 creed and an 18” barrel I would suspect it to be around 2550-2600 at the muzzle.

You can’t see inches in your scope so who honestly cares.

Search for Weaponized math on this site. lots of discussion on how to quickly get your dope and true up the software.

 

[John Glidewell]

Scope height? Barrel twist? Weather? All those need to be correct to get good data out....plus what he said ^^^^

 

[Precision Underground]

Is your sight height correct in the app?

 

[2aBaC̶a̶]

Pretty sure 100 to 200 is not enough to reverse calculate your MV. like TD said take it out past 500yds. the further the better.

 

[hafejd30]

Take it to the range and sight in at 100. Then shoot 300,500,800,1000 whatever you have available. Even just 300 and 500 for a hunting rifle is good

Then plug in the correct weather conditions, ammo, scope, bore to scope distance etc in the app

Then adjust your muzzle velocity and ballistic coefficient in the app to match it up. If it’s a hunting rifle just print or write up a drop chart for the gun

Yes your 18” barrel should be around 2500 with that ammo. Definitely not 3,000