Chronograph extreme spread and average deviations Questions

[Noonanda]

how much do you all worry about this. Can the ES and AD be overcome by nazi-like loading steps, weighting bullets as well as powders to ensure the littlest deviation. Im just trying to figure out what can be causing the ES and AD.
Also how much ES do you allow while still designating it a good load? for example today i tested my Ruger only .45 Colt load over my chrony. This is the data I got at the end.
230Gr RNFMJ
IMR 4227 24.4Gr
Win LP primers

Average Velocity: 326.6 MPS 1071.3 FPS
Extreme Spread: 31.3 MPS 102.7 FPS
Average Deviations: 9.4 MPS 30.8 FPS

Does the ES and AD seem good? Accuracy at 25 yards wasnt the best as this is a hot hard recoiling load, but it was acceptable. probably 8 inches, most of it was me not using proper SA/SP if anything.
Do you measure group size and compare it to ES and AD to determine if a load is good?

[GeoffLinder]

ES and SD are way overated as arbiters of actual accuracy. I have had rifle loads that show velocity spreads over 50fps shoot sub-MOA and have had miniscule spreads shoot like crap.

These are "indicators" of potential accuracy but not something to fret over if the load performs well downrange.

BTW, internal case volume will have more to do with velocity spread and accuracy than anything as small as bullet weight and charge weight variations in the couple tenths of a grain range.

Using one headstamp brass batches and weighing them and discarding cases outside a 2-3 grain range will do more to tighten up group size (and SD/ES) than any other combination of steps. If you aren't weight segregating cases, then anything else you do to increase control of the process is being pretty much wasted until you do that.

[Noonanda]

Thanks. I got some 7.62 Match cases I might do this with just to see how it helps.

[Fjold]

SD and ES are more important at longer ranges where the differences in velocity show up as vertical stringing.

With handgun rounds if the high ES is due to powder variations you will see larger groups due to differences in recoil.

[himurax13]

Does brass matching and case weighing show any noticeable results for 9mm or .45 acp cartridges?

[Noonanda]

SD and ES are more important at longer ranges where the differences in velocity show up as vertical stringing.

With handgun rounds if the high ES is due to powder variations you will see larger groups due to differences in recoil.

can how the powder is sitting inside the casing affect this as well for example to maintain some kind of consistancy I elevated my muzzle each time as I cocked the pistol (Ruger blackhawk S/A) so that all of the powder was back by the primer flash hole.

[GeoffLinder]

Does brass matching and case weighing show any noticeable results for 9mm or .45 acp cartridges?

Not worth it for pistol ammo as the case internal volumes are not large enough for this to be a worthwhile factor.

BUT, using one batch of brass will help pistol ammo be more consistent. Mostly due to uniform wall thickness which uniforms crimp and bullet release tension.