SD or ES

[Bottom Fodder]

Considering that all components are from matching lots, what Single thing in your reloading process have you found has had the biggest impact on lowering your ES or SD. I would like to compile a list of all the answers.

 

[Bill Norris]

Considering that all components are from matching lots, what Single thing in your reloading process have you found has had the biggest impact on lowering your ES or SD. I would like to compile a list of all the answers.

Moving from LRP to SRP brass.

 

[RabbitSlayer]

Better brass.

 

[JamesinAsheville]

which is the most important ES or SD ?

 

[Bronsin]

Neck Tension

 

[mgunderson]

which is the most important ES or SD ?

They are related. ES is a about 3x sd. Pick the one that makes sense to you and go with it.

 

[shoot4fun]

which is the most important ES or SD ?

IMO fliers don't come from SD.

 

[Straightshooter1]

which is the most important ES or SD ?

SD!

Lower SD's will result in lower ES's. I see SD's as a measure of consistency.

 

[shoot4fun]

SD!

Lower SD's will result in lower ES's. I see SD's as a measure of consistency.

SD is certainly a measure of consistency but ES is how SD is determined. One can achieve low SD but still have that one flier that will ruin a group.

 

[Straightshooter1]

Considering that all components are from matching lots, what Single thing in your reloading process have you found has had the biggest impact on lowering your ES or SD. I would like to compile a list of all the answers.

The "single thing" that's the biggest for me as been consistent powder charge measured to +/- .02 grs.

You may have seen this chart before, but I'll show it here as my thinking as to importance of various things for precision shooting is pretty much in line with it:

 

[Bottom Fodder]

Ok so far we have
Large to small primers
Better brass
Neck tension
Consistent powder charge

 

[swd]

I look at my targets and not my chronograph..

 

[Straightshooter1]

SD is certainly a measure of consistency but ES is how SD is determined. One can achieve low SD but still have that one flier that will ruin a group.

Yup, that's true. I get a lot of that on my targets.

Take two 10 shot groups, both have exactly the same ES. One group has 9 in the "X's" and one in the 8 ring, the other group has all in various places outside the "X's". Which is better?

ES just measures 2 shots no matter how many shots are involved, while SD's is a measure of them all.

 

[drop_point]

Consistent necks: tension (or interference fit), consistent thickness (turned necks), and consistent trimming/chamfer/deburr and consistent seating force indicates the consistency of the other processes.

I've found if I'm in a good node, powder weight isn't as impactful as I'd expected.

 

[Bottom Fodder]

Seen like a few has got this going down a rabbit hole.
I ask a simple question, if you can give a simple answer to my simple question thank you if you can’t please don’t derail

 

[SpencerC87]

Powder, bullet and barrel combination. If you have the wrong powder for your case, bullet weight and barrel, no amount of technique or processes implemented is going to overcome it. This is assumed to be using quality components. I don't waste my time and money on junk brass and junk bullets.

 

[GetReal]

IMO fliers don't come from SD.

I would agree. High ES is where my "fliers" come from, I believe.

Stated another way....I rarely get flyers that aren't my fault when I have low single digit SD and teens ES.

 

[ShaunBrady]

Considering that all components are from matching lots, what Single thing in your reloading process have you found has had the biggest impact on lowering your ES or SD. I would like to compile a list of all the answers.

If matching lots means premium cases and bullets with any weird ones culled, then finding the primer/powder combo that dances together the best is my vote. I use Federal Match primers as the starting point and sweep the powder speed to see which one gives the lowest overall SD in pressure ladders with 5 shot steps.

Rambling on, my take on the 2 big dilemmas for reloaders are:

1. Trying for statistically significant sample sizes to quantify random variations introduces systemic variations. Barrel heating and fouling are examples of systemic issues.

2. The random variations are a soup of several things that may either largely cancel each other in a given group or stack up and ruin your day on the next. Which happened can not be determined with a single 5 shot group.

I try to find the next big chunk in the soup and accept that any one thing may not be a big step. I record the muzzle velocity of almost everything I shoot.

SD is not a function of ES. ES is always only 2 shots. My thoughts are ES is primarily reduced by culling the outliers. The flip side is a 5 shot group isn't large enough for the SD to be a reliable predictor of ES. From either end. It isn't large enough for a reliable SD and even a reliable SD won't predict the ES for a group that small. I shoot a lot of 10 shot strings and the ES seems to almost always be close to 3X the SD plus or minus 1 or 2. My take on that is I've been largely successful in knocking the tails off a true random distribution.

 

[RSchatz]

Weighing primers


somebody had to say it

 

[Nevned]

Strictly reducing SD/ES--A&D FX 120 i scale to achieve more consistent powder charges. Nevned