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6.8 SPC Ballistic Charts.

36K views 38 replies 17 participants last post by  Ten Rounder 
#1 ·
#3 ·
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.
 
#7 ·
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).
 
#5 ·
Looks good so far. What about putting the velocity at the graduated distances, too?
 
#6 ·
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?
 
#9 ·
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.
 
#14 ·
One question P, are you going to show realistic speeds for the bullets or just run numbers? For instance an 110gr AccuBond at 3250 fps would be quite impressive but it isn't going to happen in the real world out of a 6.8 SPC. I notice your headings vary a bit between the completed load and the new ones but I'm not sure if this is a statement of intent or the appropriate speeds changed when you ran the numbers.
 
#18 ·
Can you guys look at the above link and let me know what you think.
I think this is a fantastic reference and I think you are stepping above and beyond again.

Thank you!
 
#31 ·
Awesome

Paulo, Awesome resource for a relative newbie like myself. I've just started reloading with the help of a friend who's been reloading for over 20 years. I have one of H's Xtreme uppers and this data helps my decision process when considering which bullets to load up.

Thanks for the hard work in compiling this data.
 
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