6.8 SPC Ballistic Charts.

[paulosantos]

http://spreadsheets.google.com/pub?k...uw&output=html

Can you guys look at the above link and let me know what you think. I'm going to do pretty much every bullet that is commonly used. If you guys have any suggestions, let me know. This will be a Ballistic Chart like the other chart.

[ron169]

Not bad Paulo, I think most would find it very usefull

[Zippy]

Excellent Paul, you have no idea of how much time I spent going through the charts to gather that information. Is there a way you can note what you are using as the basis for the maximum performance range. Is it just the velocity of the bullet and if so, will it be bullet specific since my memory of the figures published seem to recall part of the performance range being determined by a blanket statement by DocGKR that bullets were fragmenting/upsettig above a certain velocity. Will this be more specific?

Also, if the users are like me, they are reading the numbers to figure out how long a barrel they need for a particular performance objective. Is there any way to get a rough range of velocities in there? Might be misleading given the variety of loadings and range of velocities for the same barrels, so that might be a bad idea, or at least one to handle carefully.

[ron169]

The maximum performance range is based on 1000 ft/lbs of energy

[joshuades]

Looks good so far. What about putting the velocity at the graduated distances, too?

[Clint]

Looks good Paulo,
you probably should label the top row as muzzle vel.
The biggest thing is to add your assumptions/parameters... Bore height altitude temp etc
define what max perf range is too
I'm a big fan of OGW, maybe a ogw200 and 400 range along with max perf or 1 k ft lbs range.
You asked for it.

Also what is your main focus and audience for the chart?

[Zippy]

The maximum performance range is based on 1000 ft/lbs of energy

I think you're misreading that. Notice that the maximum performance is on a different line and is a longer range than that of the line marked "1K foot pounds." Off the top of my head those numbers looks like the point at which the bullet will fragment or dirupt. Nice touch, he gives both the maximum defensive (maximum performance range) and ethical hunting ranges (1 K foot pounds).

[ron169]

yeah, either I misread it or it changed after the first time I saw it. I probably missread it though

[paulosantos]

Once I am done, I will have a legend on the bottom explaining things.
I'm using a sight height of 2.6" and an altitude of 1000 feet.

The maximum performance range is the range in which the bullet will still fragment/expand.

The chart is just a quick reference. I really can't attach the barrel length to any velocity because it would be too complicated.
I'll see if I can add the velocity to the yards without taking up too much space.

[Zippy]

...
The chart is just a quick reference. I really can't attach the barrel length to any velocity because it would be too complicated.
...

Sadly, I think you're right. Too much variance with hand loading, commercial loading, twist, chamber...