Thread: Ballistic Calc Help

Originally Posted by stagstalker

Did anyone actually range the distance or did they just chat and assume? Because the dial difference between 300Y and 300M is going to be pretty much near on 1 MOA like you are seeing.

Yea, it was ranged at 300m. It is uncanny how close it is to getting me where I need to be and my first thought was that I had the y/m inputs mixed up but nah, checked it so many times now. It's got me stumped.

Originally Posted by ebf

Some more thoughts...

From memory, and this is going back at least 5 years - the 300m at Seddon is really only used for a couple of weekends in Jan. The rest of the time they use 300 YARDS.

Please ignore the MV on the electronic target. You are wasting your time thinking this is accurate. It is a mathematical calc using an extremely short distance (couple of inches on the microphone stalk), and does not account for the entry angle of the trajectory.

Looking at the Litz / Applied Ballistics book, your 162gr SST has the following BC:

G1 : 0.535
G7 : 0.274

I also see that your zero atmospherics and those for when you are shooting are the same. Did you record actual atmospherics when you zeroed ?

100m zero you don't need to put your zeroing atmospheres in.
I would suggest that is another brand of scope that doesn't dial correctly.
Tall target test will confirm this.
Some thing not right anyway.
Bullshit in bullshit out

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Ditch the meters to and change everything to yards with moa

Originally Posted by Kelton

Ditch the meters to and change everything to yards with moa

Don't you mean the other way around?

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Nope? I use meters with mills and Moa with yards not to say it’s the right was at all just the way I got use to things

Dates back to my first dialing scope

Gidday,

If the wind was blowing hard it could bring you elevation down significantly.

Personally I’d shoot again as far back as you can and adjust your mv to match your actual drop on target.

Originally Posted by SPEARONZ

Gidday,

If the wind was blowing hard it could bring you elevation down significantly.

Personally I’d shoot again as far back as you can and adjust your mv to match your actual drop on target.

That's what is called aerodynamic jump or AJ.
Depends if wind is coming from left or right and direction of twist of your barrel.
Interesting stuff as a mate found out when he put opposite wind direction in as when he changed it around it changed the elevation quite a bit.

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Originally Posted by Kelton

Nope? I use meters with mills and Moa with yards not to say it’s the right was at all just the way I got use to things

As a rule it doesn't matter but I always leave my measurement in meters and then I don't have to change my rangefinder options around between rifles if I have an moa scope or mils as the software sorts it out.

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Originally Posted by andyanimal31

That's what is called aerodynamic jump or AJ.
Depends if wind is coming from left or right and direction of twist of your barrel.
Interesting stuff as a mate found out when he put opposite wind direction in as when he changed it around it changed the elevation quite a bit.

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Ifi remember correctly thats called the benoulli effect I think. It's especially noticeable with .22 LR or other bulkets close to or below the sound barrier. The bullet will "climb up or down the wind ie rh twist and wind from the right the bullet climbs, from the left it drops.
I'm not sure how much effect it has at supersonic speed or at comparatively short range though.
At close ra

#1 use the Litz BC do not trust the Hornady bs hype.
#2 as OP stated perform a "Tall target test will confirm this"
ie calibrate and validate your ACTUAL scope dial up. Most VX5 & VX6 Leupies that I have calibrated dial inch per hundred yards (IPHY) or less and NOT 1.047in per 100 yd which is MOA.
#3 measure your actual mv and SD, never trust what written on the box

Originally Posted by chainsaw

#1 use the Litz BC do not trust the Hornady bs hype.
#2 as OP stated perform a "Tall target test will confirm this"
ie calibrate and validate your ACTUAL scope dial up. Most VX5 & VX6 Leupies that I have calibrated dial inch per hundred yards (IPHY) or less and NOT 1.047in per 100 yd which is MOA.
#3 measure your actual mv and SD, never trust what written on the box

I can't work out why a company that has been building optics so long can't get that sort of shit sorted out.
A tall target test should not be something you have to do.
Thank goodness there is one company that gets it perfect!

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What company is that Andy ?
just asking for those that may not be aware.

Originally Posted by jakewire

What company is that Andy ?
just asking for those that may not be aware.

Just for Jake wire, Nightforce!

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Unless you shoot 5 shot groups, it's hard to be sure if your MPI is 3 or 4 MOA from centre.
Check the units the app is using for your scope height - inch or cm ?
My app has unpredictable default unitage for things like temp, pressure and so on. Have found I'm trying to shoot through 1013 mmHg sometimes.

What the heck is "shooters MOA" ? Call iphy a spade why don't you. Like military Mils that are 1/6400 of a circle ...