Reducing ES

[6BRinNZ]

What would you guys rate as the best place to start, to reduce ES - these are my thoughts (do you agree) in order of most likely to improve;

1./ Consistent powder measurement
2./ Change primer
3./ Change powder
4./ Improve Neck tension consistency
5./ Improve Neck thickness consistency
6./ Change seating depth
7./ Measure and sort according to bullet bearing surface
8./ Change bullet
8./ Any others?

Thoughts?

 

[Keith Glasscock]

It really depends on the cartridge. and how much you are trying to reduce the ES.

Powder measured to the kernel helps, no doubt, but bigger cartridges are not that sensitive, velocity wise, to powder charges. For example, 0.1 grain of Varget (ADI2208) is good for 5 fps in a 308 win.

If your current ES is less than 20 fps, I would look at neck tension and seating depth consistency first, I would be measuring bullets second (weigh them too!).

If your ES is greater than 20, I'd be looking at the powder and primer. Change primers first, then try a different powder or powder charge.

That is just how I would approach it - I'm not an expert by any means! I get lucky with my loads and/or borrow others' good ideas.

 

[6BRinNZ]

It really depends on the cartridge. and how much you are trying to reduce the ES.

fair call - it is for a 6br and ES is 27, ideally I would cut that in half.

Is it bearing surface that you measure?

 

[jcampbellsmith]

What would you guys rate as the best place to start, to reduce ES ....Thoughts?

I wouldn't worry about ES, just because it's easy to measure doesn't mean that it is useful. Measure and target your Standard Deviation and look at the factors that SD highlights. ES measures the difference between your fastest and slowest shot, nothing else. The following article is a very good reference.

http://riflemansjournal.blogspot.co.uk/2010/02/reloading-velocity-decisions.html

Regards JCS

 

[6BRinNZ]

What would you guys rate as the best place to start, to reduce ES ....Thoughts?

I wouldn't worry about ES, just because it's easy to measure doesn't mean that it is useful. Measure and target your Standard Deviation and look at the factors that SD highlights. ES measures the difference between your fastest and slowest shot, nothing else. The following article is a very good reference.

http://riflemansjournal.blogspot.co.uk/2010/02/reloading-velocity-decisions.html

Regards JCS

Thanks - yes I have read the GAS articles, the SD for the load is also 9 which is kinda high. Shooters seem to be in two camps as to which number they care about. Currently I am working on the rule of thumb -> greater than 20fps ES at 1000 is going to cause issues. ES is a simple place to start when asking these types of questions on the internet and I know that if I reduce ES my SD will come along for the ride.

The ES/SD are from a small sample (10 shots) so not good.

In all honesty I could have worded my question using SD as really I am only after the most productive things to look at when trying to reduce SD/ES numbers when they are as high as mine. I haven't traditionally paid much attention to these numbers but my shooting is at a level now where it matters.

 

[jcampbellsmith]

..
In all honesty I could have worded my question using SD as really I am only after the most productive things to look at when trying to reduce SD/ES numbers when they are as high as mine. I haven't traditionally paid much attention to these numbers but my shooting is at a level now where it matters....

Thanks. I haven't chrono'd any of my loads recently. I might get a chance to chrono one this afternoon with this rifle.

http://www.thestalkingdirectory.co.uk/gallery/member-galleries/p4428-russell-gall-243-ackley-improved.html

To get my loads to produce a SD of less than 10, I worked hard at the necks. I neck turned, full length resized it with bushing only (expander removed) and then picked consistent necks. Secondary factors I feel in getting good SD were, accurate weighing of powder, sorting the cases into 1 gr weight ranges, using a good micrometer seater. I know my bullets vary, but I haven't sorted any yet. For the rifle above, I am just going to focus on Lapua brass and just use it.

One recent lesson was not to be fixated on one specific powder. I changed to H4350 from N165 for 142 SMKs in my 260 Rem and got much better results.

All this stuff takes a long time. It's probably taken me 2+ years to settle into a routine for prepping my brass. The latest tweak is to get the brass annealed after every 4 firings.

Regards JCS

 

[seanhagerty]

Just a thought from a rookie.

I would not overlook annealing. In my mind, it goes hand in hand with neck tension

 

[6BRinNZ]

Does anyone think that case volume (h2o volume consistency between cases) is a strong influence on ES? I haven't included this in my list at all.

 

[Steve Blair]

I wouldn't worry about ES, just because it's easy to measure doesn't mean that it is useful. Measure and target your Standard Deviation and look at the factors that SD highlights. ES measures the difference between your fastest and slowest shot, nothing else. The following article is a very good reference.

http://riflemansjournal.blogspot.co.uk/2010/02/reloading-velocity-decisions.html

Regards JCS

[br]
German's article is good and describes the case that SD is a better assessment of what the entire sample population is doing. That said: At 1000 yards I am unwilling to tolerate an ES greater than 20 because of the vertical difference on target. If I fire 20 shots that have an ES of 20, the difference between the fastest and slowest shot is ~2.5" @ 1000. That is half the X-ring before any other factors are considered. The loads I took to the Berger Nationals in February had a 20-shot ES of between 8 and 14. Those loads held vertical well. [br]
So, even if you have an excellent SD, the one shot that defines the ES will still fall low or high on the target. A large ES means that I must find the variation source and eliminate it. If I could discard a couple shots per string, I might not be as strict. But the match officials insist that everything after "Let's go for record" counts.

 

[6BRinNZ]

I wouldn't worry about ES, just because it's easy to measure doesn't mean that it is useful. Measure and target your Standard Deviation and look at the factors that SD highlights. ES measures the difference between your fastest and slowest shot, nothing else. The following article is a very good reference.

http://riflemansjournal.blogspot.co.uk/2010/02/reloading-velocity-decisions.html

Regards JCS

[br]
German's article is good and describes the case that SD is a better assessment of what the entire sample population is doing. That said: At 1000 yards I am unwilling to tolerate an ES greater than 20 because of the vertical difference on target. If I fire 20 shots that have an ES of 20, the difference between the fastest and slowest shot is ~2.5" @ 1000. That is half the X-ring before any other factors are considered. The loads I took to the Berger Nationals in February had a 20-shot ES of between 8 and 14. Those loads held vertical well. [br]
So, even if you have an excellent SD, the one shot that defines the ES will still fall low or high on the target. A large ES means that I must find the variation source and eliminate it. If I could discard a couple shots per string, I might not be as strict. But the match officials insist that everything after "Let's go for record" counts.

hmmm, looks like I might have to reword my question as I place no argument against looking at SD. I am after effort vs rewards for reducing ES/SD numbers and want to start at the place most likely to show an improvement. For instance a primer is a simple and cheap change...do most experienced reloaders start there or would they try a different powder first as primers typically have a smaller influence on ES/SD numbers. I have had good replies but am hoping to get a wider set of opinions.

 

[Steve Blair]

Here's my relative importance estimate. YMMV [br]
Cartridge choice
Powder - choice, charge weight and pressure
Case prep
Primer
Bullet - both choice and seating depth [br]
This assumes high quality components. [br]
I will add that my best results in a given cartridge are with heavy for caliber bullets, powders a little on the fast side and near (not over) max pressure, and correct and extremely consistent seating depth. Some cartridges are just a PITA to get low velocity variation. My 6mm Remington is really picky but I have finally found a combination that delivers ES/SD in the 13/5 range.

 

[The Viper]

What would you guys rate as the best place to start, to reduce ES - these are my thoughts (do you agree) in order of most likely to improve;

1./ Consistent powder measurement
2./ Change primer
3./ Change powder
4./ Improve Neck tension consistency
5./ Improve Neck thickness consistency
6./ Change seating depth
7./ Measure and sort according to bullet bearing surface
8./ Change bullet
8./ Any others?

Thoughts?

All of the mentioned items are critical. If you neglet any of them your consistancy will suffer. Find one bullet and work with it. If you are going to change components, only change one thing at a time. Both SD and ES go hand in hand. If one is out of line, it will effect the other.

When I prepare for a championship match,I start 3 months before the match date. I load three times the amount of ammo that I will need for the match. I put my fire forming barrel on, which has a perfectly matched chamber to my new barrel. I then pick one day when the temp. will be within a 10 degree range for 5 hours. I set up my canopy over my bench, so the heat from the sun won't effect my ammo. For the next few hours I shoot all my match loaded rounds thru the cronograph. One ever two minutes, so the barrel doesn't get overly warm. After each shot I take a magic marker and write the speed shown on the cronograph. At the end of the session, I sort all of the brass by speed. This tells me that the volume in the cases of the closest grouping of numbers is very close to being the same.

I will only shoot the brass in groups of less than 5 fps. as recorded on the cronograph. If you are a consistent reloader this is the only proven way to keep both SD and ES in single digits, because you have just sorted the brass by speed.

 

[jlow]

In the best of worlds, this should work but it seems that unless one can control ALL the other non-brass variables, it would be difficult to attribute differences in ES/SD to just the brass?

The frustrating thing for me, a person who comes from doing laboratory research most of my life where one can in fact control most variables is that this seems almost impossible in reloading….

I guess as they say “the prove is in the pudding”. Have you in fact confirm that brass sorted in this manner is always more consistent that the unsorted brass?

 

[The Viper]

Since you are only looking for ES and SD and the projectile only has to travel 10 feet, yes this will work.

Here is the problem with most shooters. They don't want to do the work. They don't really practice gun control. They get sloppy on the reloading bench. You have to do all the work. Leave nothing out.

If all the bullets leave the rifle at the very same speed, then they should arrive at the target at the same time and hence the same place. Loaded ammo of this grade can be guided. Now, it's up to the shooter to do the guiding.

There are many top bench rest shooters that practice this method but won't tell you. They shoot their brass and cull the ones that print out of the group.

It's the shooters job to make certain that all his components are exactly the same, within his or her control. If he's not willing to do the work, then he's just firing line fodder for those that are willing to do the work.

Do you want to know if it actually works in real competition?

go to google and type in Bob Pastor F Class.

I don't have the time left on this earth or the money to just go and expend ammunition. I go to each match to do only one thing, win if I can.

 

[jhelmuth]

To reduce ES, you ought to first look at the mirror... once you fix the part that reflects, you can focus on the other components.

 

[Nodak7mm]

go to google and type in Bob Pastor F Class.

I don't have the time left on this earth or the money to just go and expend ammunition. I go to each match to do only one thing, win if I can.

#1 - When I google that name, it comes up under the definition of "Curmudgeon"

#2 - Nope, your more like the old junkyard dog that just keeps on biting everybody, then takes another nap.. Sorry budd, but we gotta couple more dates on the line....

Rod

 

[The Viper]

You could entice me to go to ND with a batch of oatmeal cookies!!!!!!!

You guys don't have any wind up there anyway!!! hehehehe

 

[GermanS1]

Here's my relative importance estimate. YMMV [br]
Cartridge choice
Powder - choice, charge weight and pressure
Case prep
Primer
Bullet - both choice and seating depth [br]
This assumes high quality components. [br]
I will add that my best results in a given cartridge are with heavy for caliber bullets, powders a little on the fast side and near (not over) max pressure, and correct and extremely consistent seating depth. Some cartridges are just a PITA to get low velocity variation. My 6mm Remington is really picky but I have finally found a combination that delivers ES/SD in the 13/5 range.

I agree with Steve's priority list quoted above. I'd say case prep and primer are equal, but that's picking nits on my part. Steve mentioned something overlooked by others, and that's powder charge (amount). I don't mean consistency, I mean the actual amount selected. Some loads just aren't gong to SD well no matter how perfectly you load them. I see this in pressure testing quite a bit when we're looking at SD of MV and of pressure. The two come together very nicely at some charge levels but not at others.

Steve, as to the value of SD, think of it as a predictor of likely ES and I think it makes more sense. The only way to truly know the ES of your lot of ammo is to fire it all in testing, but then there's nothing left for the match. Ammunition MV is very definitely a bell curve affair. By using the best loading techniques, we fatten the center of the bell curve and shorten the tails, but we can't eliminate them, that's just real life. A low SD from a reasonable number of shots (at least 20) means you have effectively shortened the tails.

When you've done everything possible and you still get an uncalled, add shot, the best thing you can do is throw the piece of brass away. If you prepped it and loaded it right, then only the bullet or the case could have been at fault. The bullet is gone, pitch the case. Bob Jensen told me that was his technique in prepping for Camp Perry each year, over a period of months. He won the Wimbledon Cup in 1977 with his .30-338 and, as many of oyu know, loaded about 400,000 rounds for the 1992 Palma Match. Bob is a real old school kind of guy, we're fortunate to have him shooting with us and I'm especially fortunate to have him along for a lot of my testing.

 

[Steve Blair]

German, [br]
I was certainly not belittling the importance of SD as a predictor of population performance. My point was that it is possible to have single digit SD with one shot 30 fps higher or lower and that the cause must be found or eliminated. I would likely measure every relevant variable on the case and try to determine the specific problem. It none was apparent and another loading behaved the same, it would not be used. [br]
No, I've spent too much time in SPC classes not to appreciate the value of SD, particularly with the small sample populations that we use.