cast bullet ballistics app??

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  • Last Post 03 February 2021
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MaxJon posted this 23 January 2021

Hi all, new to the forum, but ive been casting for 20yrs, mainly for rifles. 

Is there such an app for cast bullet ballistics?? Or can someone recommend a decent one suitable to help with the bullet drop out to 500M max, 

Regards MJ

 

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Tom G posted this 23 January 2021

MJ,  There are two kinds of ballistic programs out there that can work for cast bullets. One is for external ballistics and the other is for internal ballistics. 

The external ballistics will work for any kind of bullet as long as you know the ballistic coefficient.  The rub comes in when you will not be able to find the BC for lead bullets as it is different for each bullet design and needs to be calculated or measured by actual firing over chronographs. It sounds like you want to calculate the drops for different distances tor trajectory., 

There is a free program available on the web that I have been using for years and has worked well.  It can be used to calculate the BC of a projectile based on input of the different weight, alloy composition, length and shape parameters of the bullet you want to know about. It will give you the BC of the bullet and when you input the twist of your barrel and velocity of the bullet it will give you the stability factor. I think you can get the info you need by using this free program.  You want to keep your stability factor between 1.5 and 2.5 for good stability in cold weather. 

Here's the URL to use the program. If you have questions on how to measure the bullet dimensions or how to use the program you can PM me and I'll try to take you through it. 

As I said, I've used it for years and it has proven to work well for cast bullets as well as jacketed. I once had a very long bullets and slow twist and it showed the bullet to be marginally stable. It shot OK in hot weather but was Key holeing on very cold days when the air was much denser. So, it turned out to be quite accurate in it's prediction for that bullet/ twist combination. I believe the author of that program also has one to calculate bullet drop at all distances.  All for free.  

 

http://www.jbmballistics.com/cgi-bin/jbmdrag-5.1.cgi

 

Tom Gray

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MaxJon posted this 23 January 2021

Thanks very much for that link I will have a look at it. I basically need to know bullet drop, for quick sight elevation adjustments.

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Bud Hyett posted this 23 January 2021

First, Tom's recommendation is good. If you understand the terminology and can add in values, this application works well. One secret is to find a comparable bullet on the NOE website, click on the diagram, then right-click and hit "Open in new image" that gives you readable dimensions with many dimension values including an estimated ballistic coefficient.

I use QuickLoad purchased from NECO products many years ago. They have a dropdown menu with cast bullet selections from Lyman, SAECO, RCBS, Lead Extrusions, and NOE. (You must go to the NOE website to get their data and insert it into the QuickLoad application, there are detailed instructions for this on the NOE website.) The dropdown menu for powders includes European and Australian powders. You can also tailor the lead alloy for harder alloy to see that effect.

A secret is NOE copies many old Lyman designs and you can find many non-current Lyman bullets in the NOE dropdown. You must know what the NOE number is to find the Lyman equivalent. 

The application also comes with QuickTarget with a hand-off from application to application for trajectory. The printed trajectory comes close on my actual firing at 100-yard to 200-yard range changes.

This application has a wide range of jacketed bullet manufacturers, I find these results from the application also match my experience shooting prairie dogs at longer ranges.

I can find many wildcats for analysis, also the "Improved" versions of many cartridges.

I also have added all the  upgrades to keep current on powders.

Farm boy from Illinois, living in the magical Pacific Northwest

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ALYMAN#1 posted this 23 January 2021

Lyman CB handbook #4 lists BC for listed bullets.

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Wineman posted this 23 January 2021

Another trick is to look at the box marked rifle elevation MOA after calculating. This is the angle the rifle is when matching the ballistics inputs. Say you want to have a jacketed sight setting that allows a cast bullet as a zero (at least in elevation). Find a jacketed load that matches the rifle's MOA field and use that sight setting to shoot cast. In JBM a 311299 (BC of 0.377) @ 1600 fps is 15.5 MOA for a 200 yard zero. A 168 grain AMax at 2600 fps (BC 0.475) zeroed for 475 yards is 15.3 MOA. Your sight dope for a jacketed bullet can be cross referenced for cast. Windage may vary somewhat. Its not perfect but it should have you on paper.

Dave

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Millelacs posted this 24 January 2021

.     Lyman CB handbook #4 lists BC for listed bullets.

Lyman CB handbook #3 also shows Ballistic Coefficients  in the ballistic section starting on page 298.

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barra posted this 03 February 2021

I use StrelokPro 

 I found G1 on bullet b.c. to work for me

The b.c. and velocity can be had from manuals etc but it is often a bit ambitious sometimes.

I don’t have a crony but use my drop to get velocity at different ranges.

‘Shooting over someone else’s is great  start.

I then tweek using the b.c or velocity on the drop at distance and wind deflection.

I think I should get 24 moa drop but have 28 then I will check my wind deflection.

if it’s right I will adjust the velocity.

there is a correction calculator that gives you the option.

Works for me.

But I only shoot mouse fart loads to 300mtres for fun sometimes so it may not apply to what you are doing.

 

 

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