ES & SD

JCSC · Feb 28, 2021

I have asked quite a few questions as I am just learning various cause and effect.

Is it safe to assume that most variations in numbers are due to inconsistency in my process? Also, knowing that some guns hate a particular pill. Does the bullet basically play no part in the SD and ES. Thus, you could have great numbers and a very poor performing projectile?

I thought I made some pretty good rounds, but my numbers told me differently, so I am fine tuning things. With that said, I have no doubt that the loads I made up today are the best I have ever produced.

v8stang289 · Feb 28, 2021

JCSC said:
Is it safe to assume that most variations in numbers are due to inconsistency in my process?

Not necessarily, I've found most guns will have "nodes" around certain charge weights where ES, SD, and group sizes are at a minimum. It's when everything comes together that the rifle "likes"
Inconsistency can play a part in ES and SD numbers, but I wouldn't say that's the biggest contributor.
Different charges, seating depths, primers, and other factors may effect how consistently the powder burns, how the bullet enters the lands, the position of the barrel when the bullet exits. There are a lot of factors in play.
That's why we play with seating distance and do ladder testing to determine what a rifle likes.

fxvr5 · Feb 28, 2021

With respect to handgun calibers, the specific powder matters the most. Some are known for smaller SD and ES than others.

The question of whether it matters or not depends on your purpose. It does not seem to matter for accuracy at typical handgun distance (i.e. 25 yards) for the typical handgun. https://americanhandgunner.com/handguns/exclusive-consistent-velocity-accuracy/

JCSC · Feb 28, 2021

Interesting. I am very familiar with the ladders, nodes, etc, but never considered the node played a part in better numbers. It makes sense and this is exactly why I asked the question.

JCSC · Feb 28, 2021

fxvr5 said:
With respect to handgun calibers, the specific powder matters the most. Some are known for smaller SD and ES than others.

The question of whether it matters or not depends on your purpose. It does not seem to matter for accuracy at typical handgun distance (i.e. 25 yards) for the typical handgun. https://americanhandgunner.com/handguns/exclusive-consistent-velocity-accuracy/

I agree. Doesn’t even matter for most hunting rifle situations, unless extreme distances come in to play.

my question was specific to a bolt rifle I have been playing with and really just learning the 6.5 creedmoor cartridge.

JFrank · Feb 28, 2021

Great question..
Load development is said to be three areas
Combustion ( powder primers neck tension)
Harmonics ( barrel timing via nodes /seating /action bedding)
Ballistics ( bullet choice etc.)
Many times at long range the tightest /smallest groups have less the stellar Chrono graph numbers.
The BR fellas I know don't concern them selves too much with it.
I think combustion adjustments will effect ES more than ballistics.
Maybe a couple of the experts will weigh in.

BTW @JCSC I had a significant decrease in ES by switching scales.

Walkalong · Feb 28, 2021

fxvr5 said:
With respect to handgun calibers, the specific powder matters the most. Some are known for smaller SD and ES than others.

Agreed, and some rifle powders are also known for small ES/SDs if loaded right. Any powder can have poor numbers with a bad load.

JCSC · Feb 28, 2021

Jim

in regards to scales, I am in the market. Always use a RCBS M500 beam and it works fine. I am now playing with a frank ford 750 digital. Just to do some second checking. It’s a very inexpensive digital.

I want a charge master lite, but haven’t pulled the trigger yet, nor have I done my diligence on it.

JFrank · Feb 28, 2021

Hey buddy
When you get all this stuff figured out then share with me.
J

JFrank · Mar 1, 2021

I thought I would share this post from DKhunt (aka Matt Kline holder of 7 long range world records)

Nature Boy · Mar 1, 2021

South Prairie Jim said:
I thought I would share this post from DKhunt (aka Matt Kline holder of 7 long range world records)

Yeah, well, what the hell does he know

JFrank · Mar 1, 2021

OMG "
I spilled my coffee laughing so hard.

Thx buddy you made my day.
J

Blue68f100 · Mar 1, 2021

Nature Boy said:
Yeah, well, what the hell does he know

He knows what's on paper trumps ANY data collection on fps, es,sd.......

Bat Rastard · Mar 1, 2021

Does ES & SD really matter on pistol ammo? (Within reason) Pistol are not usually shot at distances that would show differences on the target.
I know we want to eliminate all inconsistencies.
This is more of a philosophical question than anything.

Walkalong · Mar 1, 2021

ES of 10 to 15 is good by the way......SDs to go with it will be single digits.......

fxvr5 · Mar 1, 2021

Bat Rastard said:
Does ES & SD really matter on pistol ammo? (Within reason) Pistol are not usually shot at distances that would show differences on the target.
I know we want to eliminate all inconsistencies.
This is more of a philosophical question than anything.

See the link at post #3.

ES & SD

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