Probably should be in the stupid marksmanship question

[Shootinsurveyor]

I went out to true my ballistic software today(StrelokPro ). I have a muzzle velocity of 2770 from a magnetospeed using Barnes 6.5CM 127LRX Factory ammo. Seemed reasonable as my tikka is always slower than stated muzzle velocity of 2800+-Zeroed at 100. Go to shoot 300. End up with adrop of 18.00. Drop based on muzzle velocity should be around 12.8 inches. This is almost seven inches different than what is calculated based of of my Magnetospeed MV. If I true this using actual field drop it changes my MV to 2400 something. It was a little breezy. Could a head or tail wind affect my drops so much. The clicks seem to be matching up with my actual drop in inches. I never touched the knobs after zeroing. Just measured actual drop on the target with ballistic advantage photo app and a tape measure. Not sure what setting I’ve got screwed up. My group was just under 3” with maybe a inch or vertical dispersion among the 3 shots. Should I even be worried about this for hunting under 300 yards?

 

[Lowlight]

Actual MV and Software has become just about meaningless,

It's the only way the software can adjust is by changing the MV so that makes the number meaningless.

Also, don't use Inches or whatever, use the actual Dope either MOA or Mils

1.2 is closer to right than wrong, your numbers are fine, Tikkas are slow, and not 30fps slow, but 150fps slow.

predictions are based on the available information, and that information is translated in different ways by different programs.

The best practice to use software so you don't have these questions,

1. Zero Rifle at 100 yards,
2. Dope Rifle to available distance FIRST without software
3. Match Real World DROPS to the software by adjusting MV to 600 and BC after 800.

 

[Shootinsurveyor]

Thanks Frank. If I match real world drop, it would say my muzzle velocity would be in the 2400 range which I have a hard time believing. I shoot American Gunner 140s at avg 2647 which didn’t seem “tikka” slow. I have experienced being 100fps slower than box speed on the 143eldx so I’m aware of what you brought up. I have a 243 that I have magnetospeeded and used that to make good hits at 479yds which was as far as I could shoot at the time so I’m just trying to figure out the variables that I may have screwed up along the way. Thanks again for spreading the knowledge and help.

 

[Lowlight]

Who cares what it says if the data matches ...

 

[Powder_Burns]

Atmospheric data can be a factor as well. My 600yd dope can be a few moa different if I’m not using the correct temperature/altitude/pressure etc. Granted I’m a few thousand feet above sea level too.

I think software solutions have made a lot of us lazy and complacent, you just assume its going to be correct if your muzzle velocity and published bc numbers are good.
Nothing beats real world hard dope.

 

[Dthomas3523]

Ya, what Frank said.

People would be much better off to just take their rifle:

Zero @ 100
Shoot 300, 600, 800, 1,000 with waterlines
Write down actual dope and the temp/pressure/altitude (humidity just set to 50%)

Then go home and input whatever you need for MV and BC to get the same numbers as 3,6,8,1k with the environment set the same.

And then move on.

 

[Shootinsurveyor]

Come on man. Ain’t nobody got time for that (or ammo). It’s just for hunting out to 300 so maybe I’ll just zero at 200 and let it ride. Have to verify zero in Montana when I get there anyway.

 

[Josh1978]

Ya, what Frank said.

People would be much better off to just take their rifle:

Zero @ 100
Shoot 300, 600, 800, 1,000 with waterlines
Write down actual dope and the temp/pressure/altitude (humidity just set to 50%)

Then go home and input whatever you need for MV and BC to get the same numbers as 3,6,8,1k with the environment set the same.

And then move on.

For a newb who is just getting into shooting, can you explain what waterlines are and how they work at different distances? Thanks,

 

[Powder_Burns]

Its just a horizontal stripe across the target so you can determine how high or low your impacts are.

 

[isofahunter]

Was the MS on the rifle for the 300 yard group?

 

[Dthomas3523]

For a newb who is just getting into shooting, can you explain what waterlines are and how they work at different distances? Thanks,

 

[Shootinsurveyor]

Was the MS on the rifle for the 300 yard group?

Nope, I used it the other night at the indoor range. Other than shooting sub MOA groups at 300 yards with a lightweight hunting rifle, this trip was a waste for data gathering. Still better than a day at work

 

[seansmd]

You have the answers, the bullet didn't lie, odds are you entered something incorrectly, or it's that slow.

Regardless, if your shooting at 300 that's your dope, as others have said if you want to use a ballistic calculator you need to adjust it to your rifle and your dope.

 

[Newbie2020]

Believe the bullet.