Thread: What is "ES"

Maybe this is a silly question but even google can't seem to answer it for me, when reading different discussions around reloading I often see the term "ES" used. Anyone care to enlighten me?

Extreme Spread, difference between lowest and highest velocity.

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the lower this is the better. This CAN be a reflection of how consistent you reloading is.

15fps is great

80fps is shit

Originally Posted by Uplandstalker

15fps is great

80fps is shit

But all things aside, 80 fps is will not be an issue out to a fair distance😆




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That's right in my F class rifle a drop of 70fps gives me 1 MOA lower impact point not really a problem in a hunting rifle until out past 500 metres,
at short range under 200 metres might not even notice it.

Thanks, just been out testing some loads and I was only getting 20fps or less difference between shots so i must be doing something right

Originally Posted by Ryan_Songhurst

Thanks, just been out testing some loads and I was only getting 20fps or less difference between shots so i must be doing something right

Yup you are. That's pretty good. As good as you will ever need hunting at conventional ranges.
Start annealing and it could get even lower😆

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ES stands for 'extra shit' to worry about when a clover leaf is no longer enough

And here I was thinking enviroment southland

Is there a "traditional number" of shots ES is measured over ? The more shots you fire the bigger ES you are likely to observe, just like "spread of centres" group size.

Originally Posted by Bagheera

Is there a "traditional number" of shots ES is measured over ? The more shots you fire the bigger ES you are likely to observe, just like "spread of centres" group size.

I just shoot a one shot group, then my ES is amazing

Originally Posted by Gibo

I just shoot a one shot group, then my ES is amazing

You're not alone mate, I suspect most of these "my factory rifle shoots 0.5 moa groups all day long" stories are due to single-shot groups

Originally Posted by ebf

You're not alone mate, I suspect most of these "my factory rifle shoots 0.5 moa groups all day long" stories are due to single-shot groups

My best is ES of 6. Four shot group out of the Remmag. It doesn't mean much to me if the groups are shit though

As a barrel heats up, speed will vary no matter how good your 1 shot ES is.😆
How much depends on your barrel and how anal you are at reloading your ammo.

I have tested 5 rnds over a half hour period and it was pretty good.
As said above low ES does not mean you will have good accuracy.

But as my rifle is a hunting rifle primarily and with shooting the odd bit of steel for shits n giggles I only see benifit in testing mine over time, cold bore.

I keep records or if I am lazy the V3 has all my strings recorded.

If your reloading practice is sound and you have a low ES over say 10 shots there is no reason not to assume it will be the same throughout.
If your a hunter shooting conventional ranges as long as it is under 100 fps it won't be an issue.

4 things that have improved my ES the most are weigh sorting, annealing, graphite and HBN coating my projectiles.
I sacrifice a bit of velocity by coating my projectiles but it's only a click or 2 on the dial at the end of the day.




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As already stated low ES doesn't guarantee a good group, conversely high ES doesn't necessarily give a bad group, well at 100yds at any rate. High ES will certainly affect vertical though at extreme ranges but for hunting purposes/ranges is not a problem. Bought my first box of factory ammo for many years, mainly to get the brass, and the ES was extremely shite up around 50fps, but the accuracy was shite also - Win 223.

The groups shot below were with my 6.5x47L (yeh the bottom 2 shots hardly qualifies as a group), 130gr Bergers, RL15. ES for 6 shots was high, nudging 30fps. Fired the first 2 shots and then adjusted up 2.5MOA and fired the last 4. Shot quickly, well at the speed I would normally shoot under F Class rifle range conditions. Decided to not use it as a long range load but to do a bit more development. Hopefully can reduce the ES but on the flipside the size of the group may grow.