Ballistics caculator help

[WWP2012]

I looked thru the Sticky on this and used the working links plus several others to ballistic calculators. I cannot come up with a accurate chart to save my life, they all say I should have way more drop than I actually do. I need some help figuring out why.

Details confirmed at range on paper.

7mm Mag 150g Barnes TTSX Boattail
Barnes Listed BC .450
FPS average 3110 Via Magnetospeed
Wind was from 9 oclock at 10-15 MPH
Temp was 83 degrees
Barometer was 30.19
Humidity was 43%
Shooting angle -10 degrees
Elevation 641'
Scope height to center of bore 1.750

200y zero
300y 2.5 MOA
400y 4.75 MOA
500y 6.75 MOA

I am looking for a app that has the Barnes bullets listed also for a iPhone. I also have tried to create a custom label but their ballistics don't match either, although they are the closest so far.

Thanks for the help.

 

[Eric H]

Have you tried STRELOK? It's not bullet specific but it's pretty good. A friend turned me onto it and he's using it for 1k yd competition.

 

[WWP2012]

I will give it a look.

 

[Defiance7mm]

I use the Shooter App. If your input is good it'll be right on the money.

 

[Barrelnut]

A lot of times, you have to adjust the published BC of the bullet so that the results of the calculator match the results/drops you are seeing on target. You can also adjust the velocity inputs on the app to match your results on target. This is pretty normal.

Like said above try Shooter or better yet the Applied Ballistics app. They are not free, but really a bargain for what you get. They have verified and tested BCs for a slue of bullets that tend to give real world results.

IMO, for the 500 yard results, you have above, I would adjust the velocity inputs to the app until they match your results at 500. You may then find that everything closer in magically lines up.

 

[WWP2012]

A lot of times, you have to adjust the published BC of the bullet so that the results of the calculator match the results/drops you are seeing on target. You can also adjust the velocity inputs on the app to match your results on target. This is pretty normal.

Like said above try Shooter or better yet the Applied Ballistics app. They are not free, but really a bargain for what you get. They have verified and tested BCs for a slue of bullets that tend to give real world results.

IMO, for the 500 yard results, you have above, I would adjust the velocity inputs to the app until they match your results at 500. You may then find that everything closer in magically lines up.

I tried the Applied ballistics and also bought the Strelok app. They are all close but not quite close enough. If I do it for 500 the 400 is 4.2 MOA verses 4.75 actual. Which makes me wonder as I stretch it out what the data verses actual is going to be.

It's been a while since I did a zero. I am wondering if I didn't zero this for 100 and not 200 as I shot it at both.

I will head to the range again in the morning to confirm my zero. I will update what I find.

 

[venatic]

I bet it's your zero... that's a common issue

 

[Mach 1]

You can use any ballistic calculator you want but you always need to verify the impacts and will almost always need minor tweaking. Ballistic calculators are kinda a rule of thumb thing. They will get you very close but like Reagan said, trust buy verify

 

[bigngreen]

The zero and the actual range of each target verified with a range finder are critical!!

 

[User4302021]

At the ranges you are shooting, BC isn't a factor. As long as you are in the general vicinity of correct BC, it should line up. Out to 500 yards, speed is by far the largest determining factor of trajectory.

If it is coming up wrong on multiple programs, it is an easy bet that there is a problem elsewhere in the process.

 

[WWP2012]

You can use any ballistic calculator you want but you always need to verify the impacts and will almost always need minor tweaking. Ballistic calculators are kinda a rule of thumb thing. They will get you very close but like Reagan said, trust buy verify

That's why I went and shot them 300/400/500 yesterday to confirm it all. All set with my rangefinder. I didn't bother with 200 as that is my normal zero. But I've shot this at 100 recently for for a new load. Which has me wondering if I didn't move the scope.

 

[sea2summit]

I tried the Applied ballistics and also bought the Strelok app. They are all close but not quite close enough. If I do it for 500 the 400 is 4.2 MOA verses 4.75 actual. Which makes me wonder as I stretch it out what the data verses actual is going to be.

It's been a while since I did a zero. I am wondering if I didn't zero this for 100 and not 200 as I shot it at both.

I will head to the range again in the morning to confirm my zero. I will update what I find.

Have you purchased that round in applied ballistics? If not, it won't be 100% accurate with the BC calculations at each velocity from my understanding. You can also manually change BC/velocity data in the app to match real life performance.

Also .5 MOA at 400 is easily atmospheric influences. Can we assume you are correctly capturing/applying that?

ETA, on the AB app if you have a crosswind you will typically see .5 MOA high at 100 and on down the line for aerodynamic jump. Set the wind to 0/180 degrees or 0 MPH.

 

[BallisticsGuy]

OP, please email ballisticxlr at gmail and I'll provide you a link to download your custom ballistics table (a freebie I do for LRH'ers that seem to need it). My app brings the following results which are within the margins of normal shooter error and group size:

1.9 @ 300
4.1 @ 400
6.6 @ 500

If you tell me what scope and reticle you have I can also make you a custom BDC table.

As an aside, I didn't have to tweak anything in my app to get these results. It just worked.

 

[PApa Black]

I looked thru the Sticky on this and used the working links plus several others to ballistic calculators. I cannot come up with a accurate chart to save my life, they all say I should have way more drop than I actually do. I need some help figuring out why.

Details confirmed at range on paper.

7mm Mag 150g Barnes TTSX Boattail
Barnes Listed BC .450
FPS average 3110 Via Magnetospeed
Wind was from 9 oclock at 10-15 MPH
Temp was 83 degrees
Barometer was 30.19
Humidity was 43%
Shooting angle -10 degrees
Elevation 641'
Scope height to center of bore 1.750

200y zero
300y 2.5 MOA
400y 4.75 MOA
500y 6.75 MOA

I am looking for a app that has the Barnes bullets listed also for a iPhone. I also have tried to create a custom label but their ballistics don't match either, although they are the closest so far.

Thanks for the help.

https://www.jbmballistics.com/ballistics/calculators/calculators.shtml