ES and SD question

[DFHarley19]

Here are a couple of articles that talk about SD and ES. The recoil web article has some nice graphics for various ranges. The 2d pr blog boils it down to once you are under 10 SD, then compared to a load with an SD of 3, less than 2 shots out of 100 will be misses on a 1k 20" target because of velocity fluctuations. The overall summary shows the biggest impacts.

I use an amp annealer, and a auto trickler to weigh charges to the .02. How the rifle likes a powder and that specific amount still comes into play in a big way. For a 5 shot chrono, most of the loads I end up using are about a 5-8 with new brass. Once the brass gets older or the barrel wears, then that usually drops to 10-12. My ESs usually go from low 20s to about 40 as the barrel wears. By the time I see ESs of 40'ish, I'm also seeing random flyers and getting frustrated when I try to shoot long. Then the rifle gets a new barrel.

How Much Does It Matter? Overall Summary

As long-range shooters, we tend to obsess over every little detail. After all, we’re trying to hit r...

precisionrifleblog.com

How Much Does SD Matter?

As long-range shooters, we tend to obsess over every little detail. After all, we’re trying to hit r...

precisionrifleblog.com

Chasing Muzzle Velocity Standard Deviation and Extreme Spread for Precision Rifle Shooting

How important are muzzle velocity, standard deviation, and extreme spread for long range rifle shooting? Learn how to figure this out... Read more...

www.recoilweb.com

That is what I need to read! Thank you!

 

[entoptics]

Took the time to do a little math for you using JBM Ballistics. Used conditions typical of where I shoot/hunt most (2300', 50°). Warmer, higher = less shift, colder, lower = more shift.

Generic 30-06 With 178 gr ELD-X. 50 fps ES.
2775 fps = 21.2" drop @ 400 yds, 72" @ 600 yds, 161" @ 800 yds, 301" @ 1000 yds.
2825 fps = 20.3" drop @ 400 yds, 69" @ 600 yds, 154" @ 800 yds, 288" @ 1000 yds.

So for 50 fps ES, that's roughly 1/4 MOA @ 400, 0.5 MOA @ 600, 1 MOA @ 800, and 1.25 MOA @ 1000 yds.

 

[Rilow]

Took the time to do a little math for you using JBM Ballistics. Used conditions typical of where I shoot/hunt most (2300', 50°). Warmer, higher = less shift, colder, lower = more shift.

Generic 30-06 With 178 gr ELD-X. 50 fps ES.
2775 fps = 21.2" drop @ 400 yds, 72" @ 600 yds, 161" @ 800 yds, 301" @ 1000 yds.
2825 fps = 20.3" drop @ 400 yds, 69" @ 600 yds, 154" @ 800 yds, 288" @ 1000 yds.

So for 50 fps ES, that's roughly 1/4 MOA @ 400, 0.5 MOA @ 600, 1 MOA @ 800, and 1.25 MOA @ 1000 yds.

Thank you for that. It puts things into perspective

 

[BrentM]

Took the time to do a little math for you using JBM Ballistics. Used conditions typical of where I shoot/hunt most (2300', 50°). Warmer, higher = less shift, colder, lower = more shift.

Generic 30-06 With 178 gr ELD-X. 50 fps ES.
2775 fps = 21.2" drop @ 400 yds, 72" @ 600 yds, 161" @ 800 yds, 301" @ 1000 yds.
2825 fps = 20.3" drop @ 400 yds, 69" @ 600 yds, 154" @ 800 yds, 288" @ 1000 yds.

So for 50 fps ES, that's roughly 1/4 MOA @ 400, 0.5 MOA @ 600, 1 MOA @ 800, and 1.25 MOA @ 1000 yds.

Nice work. Exactly my point. Just didn't want to sit and play out all the numbers today.
This a 400 yard target and the left group is 6 charges and 150 es

 

[jasonco]

If your max is 400 yards, you needn't let it keep you up at night, with worry. After 600 yards, that's when ES & BC start to matter, SD is a part of ES, so if your ES is crap, don't worry about the SD or shooting past 400 yards.