30 nolser velocity vs drop chart

[30noslercam]

So I've just had a 30 nosler built and I'm really happy with it. It's a trued Remington with a 26" 1:9 bartlein barrel and brake. Topped it off with a new shv 5-20x56. The Smith did up a conservative load with the 208 eldm doing 3040 fps under half moa over 86 grains of 2217. Muzzle velocity taken from a lab radar. I took it out yesterday and the accuracy was excellent. However using the 3040 velocity I was well high at 400 and further out. We shot out to 1600 yards and to get centre of the gong we had to change our drop chart to 3200fps. We then shot back in from 1600, 1100, 788, 600,400 yards and all were dead centre hits running from the new velocity. Any ideas why? The chrono is normally accurate. I'm really happy with accuracy and confident with where the projectile is hitting, just dont know why.

 

[Overkill338]

I don't understand how its hitting low, if you had to change the drop chart to a higher velocity. Seems like you would have been shooting high.

 

[30noslercam]

I don't understand how its hitting low, if you had to change the drop chart to a higher velocity. Seems like you would have been shooting high.

Once velocity was changed to 3200 on the ballistics app it was shooting exactly where it should. At 3040 where chronograohed from the muzzle it was low.

 

[Overkill338]

Once velocity was changed to 3200 on the ballistics app it was shooting exactly where it should. At 3040 where chronograohed from the muzzle it was low.

I understand that part. Changing the velocity would indicate its moving faster than chronographed, right? Which means to adjust drops, would take more clicks than needed. Essentially you would have been shooting high (ie: only needed 5 moa of adjustment, but you made 7 for the 3040).

Someone help me if I'm seeing this wrong. The only thing I can think of, is the BC was enter as a lot higher than it should be.

 

[30noslercam]

I understand that part. Changing the velocity would indicate its moving faster than chronographed, right? Which means to adjust drops, would take more clicks than needed. Essentially you would have been shooting high (ie: only needed 5 moa of adjustment, but you made 7 for the 3040).

Someone help me if I'm seeing this wrong. The only thing I can think of, is the BC was enter as a lot higher than it should be.

I think were saying the same thing. Real world data is showing it is moving faster than 3040. Requiring less clicks as its hitting the target faster. At 3040 I required 11.5 clicks at 300 yards where as 3200 I required 10 if that makes sense. All I can think of is bc isnt correct. However came straight off the hornady box. And you are correct, I got muddled, it was high not low with the original speed.

 

[Overkill338]

I think were saying the same thing. Real world data is showing it is moving faster than 3040. Requiring less clicks as its hitting the target faster. At 3040 I required 11.5 clicks at 300 yards where as 3200 I required 10 if that makes sense. All I can think of is bc isnt correct. However came straight off the hornady box. And you are correct, I got muddled, it was high not low with the original speed.

Ok, now we are the same page. The BC is really all I can think of, but then again, I'm not an experienced long range guy.

 

[Overkill338]

 

[Overkill338]

Inside the Hornady ballistic app, it says the BC is 0.670 G1. On the website it says 0.690.

 

[Overkill338]

200 yard zero, 3040, BC 0.67

 

[L.Sherm]

Are you putting in the correct zero, 100, 200 or

 

[L.Sherm]

160fps is alot I doudt very seriously you your going 3200 fps with a 208 in a 26" tube.

 

[30noslercam]

160fps is alot I doudt very seriously you your going 3200 fps with a 208 in a 26" tube.

I also doubt the velocity is 3200. I'm guessing the bc is out. 100 yard zero.

 

[dfanonymous]

Either your muzzle velocity was off on the chrono or the BC is off. Probably the BC.

BC are just models. Custom BC is the only way to get things trued. Basing your BC off a g7, then it's best to true it around 800 or further, then at transonic.

 

[30noslercam]

Either your muzzle velocity was off on the chrono or the BC is off. Probably the BC.

BC are just models. Custom BC is the only way to get things trued. Basing your BC off a g7, then it's best to true it around 800 or further, then at transonic.

I'm guessing the bc is off. The lab radar is pretty consistent. Like stated I went off the g1 bc of .690 that hornady provided. Will have to adjust to suit.