Consistent ES and SD

[JustMe2]

I have been reloading for many years and struggle with consistently achieving single digit ES and SD. I use a lab radar with the magnetic trigger and rarely not capture a shot. My reloading practices is good brass (lapua) CCI primers 200 or 250 depending on the caliber (6.5 creedmoor or 6.5 PRC) Hornady 140 ELDM or 143 ELDX, each rifle is a custom action and better then average barrels (proof on the PRC and Benchmark on the creedmoor). All though each rifle has produced .250 or better groups if I do my part I struggle with single digit ES and SD. Typical powders I have tried are IMR OR Hodgons H's or Retumbo. I use a FL dies and bump brass back 2-3 thousands. I use a carbide mandrel to set neck tension at 2 thousandths. I clean and brush inside necks after resizing. I typically set my jump at 40-50 thousandths to start and tune as needed. My powder scale is the Creedmoor digital and I calibrate and weigh to the kernel.

What am I missing? Is it my components or am I missing some important step. Oh I anneal every 3 firings.

Stop chasing ES and SD because statistically your sample size is too small to have any "confidence" in your data. Listen to Hornady talk about 1000s of rounds fired in their Hornady video "Is Your Group Size Too Small", EP50.

 

[RockyMtnUT]

Curious if you sort after fireforming/trimming or before? I don't trim new brass. I sort before firing. I don't want to, or have the time to re-sort "once fired" again.
Have you marked some of the outliers and tested them against the 30 to see if there was an actual difference? Yes, alway a difference. Some brass varies quite a bit that it has no place for me to even reload it. Generally I end up with 3 to 4 groups of brass that are really close to each other.

 

[Mike Matteson]

Choosing a powder that packs the case keeps my ES/SD lower. I hum around 4-12SD. I accept anything under 20 when the recipe is shooting bug holes. Optimal combustion with low SD is only going to come into play at 1000yds and in a match shooting for inches.

I don't match shoot, but I want may ammo in very low ES/SD anyway.
I would look at primers, and primer seating depth. Scale the powders also. I use a powder scale all the time. Measure first the check with the scale. I have several Lyman #55 powder dumps. I set one up for the powder that I use for that round. I don't change it after that. Generally can throw a very close charge of powder with them. You have to do everything the same way each time to get very close.

 

[Dirtrax]

What is your ultimate goal? Are you shooting ELR?

Some of the F class guys are going away from ES/SD completely. They are finding that it does not necessarily correlate to what they're seeing on target down range.

Pick your tightest shooting loads and shoot them at the farthest distance you plan to. I bet your vertical dispersion will be LESS than you think it is. The whole ES contributing to higher vertical dispersion is not necessarily true; I won't pretend to understand the physics but it's well documented.

It's called positive compensation. Start your research there.

 

[parshal]

I've had the most meticulously prepped brass have horrible SD/ES and I've had brand new pulled from the box with zero prep have fantastic SD/ES across large sample sizes. It's all a mystery to me. Just use what shoots best on the target.

 

[OFFISHN]

I usually dont respond to these types of questions as there tend to be lots of conflicting answers, however, i have test over 1,000 rounds in the last 4 months. There is more to the subject then I can write here, so here briefly is my observation.

Low ES/SD is about consistent ignition Percentage of case fill doesn't impact ignition. Doesn't impact es-Sd

Use high end brass eliminates a lot of issues.
Sorting brass and primers has little to no impact on ES/SD
Anneal-trim every time, (while I mandrel, have not noted impact ES/SD
Bullet of consistent weight & bearing surface
Measure powder to .02 (V4 or SuoerTrickler make this easy)
Find right powder - primer combo.
For PRC changing from fed 215 to 210 primer SD when from 26 to 4 over 10 shot strings

with PRC find a node at least .4 grains wide with little velocity change.

Hope this helps and doesn't add to the confusion.

Nope that's good info.

 

[OFFISHN]

I thought I would share some of the 100yd groups these rifles have produced. I actually learned a few different things from those who responded. Thank you! I recently started stretching the legs on both these rifles. The creedmoor with the current scope has enough MOA to shoot out to 1300. I have been one shot and on from 100-800 but things change after 800 out to 1300. It's not one shot and on but all have been contacted after 2-3 rounds and reading the wind correctly. The PRC is similar at 1 shot and on out to 800 but again things change after 800 all the way out to 1800. There is enough MOA to go 1600 with the current scope and past that I have to use the ballistic plex reticule to go 1800. I thought a lot of the difficulties going past 800 was the ES and SD. My standard ES and SD have been mid 20's ES to mid teens SD consistently but I seldom get single digits across the board. I felt some of the past 800 yards was due to ES and SD. But after all your input I see a few things I can try to lower these numbers but I also need to shoot a longer string to get a good representation of ES and SD. All of these are only if I do my part and as we all know there are good days (shown) and bad days.

 

[TopPin]

I thought I would share some of the 100yd groups these rifles have produced. I actually learned a few different things from those who responded. Thank you! I recently started stretching the legs on both these rifles. The creedmoor with the current scope has enough MOA to shoot out to 1300. I have been one shot and on from 100-800 but things change after 800 out to 1300. It's not one shot and on but all have been contacted after 2-3 rounds and reading the wind correctly. The PRC is similar at 1 shot and on out to 800 but again things change after 800 all the way out to 1800. There is enough MOA to go 1600 with the current scope and past that I have to use the ballistic plex reticule to go 1800. I thought a lot of the difficulties going past 800 was the ES and SD. My standard ES and SD have been mid 20's ES to mid teens SD consistently but I seldom get single digits across the board. I felt some of the past 800 yards was due to ES and SD. But after all your input I see a few things I can try to lower these numbers but I also need to shoot a longer string to get a good representation of ES and SD. All of these are only if I do my part and as we all know there are good days (shown) and bad days.

My opinion on the mater of why your group is falling off beyond 800 yards would be one or a couple of factors. I personally don't true bc in a Kestrel or any other program inside of 700yards. Trust the target. If you're hitting low or high on drop data it's a velocity or bc factor. If you're shooting in consistent weather conditions. Humidity, 20 degree temp swing, wind, barometric pressure, ext are all factors along with barrel twist, bullet choice, reloading practices ext. try and true your drop to consistently impact at 700-1000 yards. The fall off point in true bc is typically between 800-1000 yards in my findings. Most projectiles velocity start to have a parachute effect with velocity, and bc after 800 yards. Typical fall of point in velocity where the projectile typically starts slowing down at a more rapid rate. Just my opinion.

 

[Mike Matteson]

Nope that's good info.

I never really understand the need for Mag Primers in cases that hold less or about 75 grains of powder or very close to that. Above that then I would think mag primers would come into play. I don't have any rifles chamber for the larger powder charges. My biggest rifle is a 338WM. I have several other belted mag but in smaller calibers.
The other is I have held my ranges down to 500yds.

 

[Texis]

From my research, Anything 15 and under will do. The wind will cause more misses than SDs in the mid teens at my hunting distances (under 700).
In my experience you either anneal every time, or not at all. Annealing every so many firings is a variable, variables in hand loading is bad. Annealing softens the brass and changes your neck tension.
I don't want to anneal every time, so I don't anneal anymore, and without negative consequences to my groups or SDs.
You said "Lapua", which I know will fire 20+ times without issue. Yes, each firing slightly changes the temper on the brass, but not nearly as much as annealing.
Did I give up on super low SDs.. sorta. Came to the conclusion I needed to learn the wind better, my hunting distances were 600 or less and firing only 1000-1200 rounds per year, I wasn't going to get good enough for 5 fps to matter.
For me, some hand loading rabbit holes aren't worth the trouble.. but like most, I have to chase them for a while before I come to that conclusion
I ask myself, was I developing a accurate, reliable Long Range hunting load, or trying to bench rest shooting at 1000yds? It is hunting loads I'm after, and 15 fps SDs is more than adequate for that.
As for not annealing, I don't shoot magnums. My 708 is easy on brass so that is probably also a factor of my brass' longevity.

 

[L.Sherm]

Way to many people chase that magic number, untill you start just believing what your targets are telling and not just at 100 yards instead of a number there will be alot of wasted time, components and barrel life.
Sometimes I think ya just need to leave your chrono at home.

 

[aschler]

I usually dont respond to these types of questions as there tend to be lots of conflicting answers, however, i have test over 1,000 rounds in the last 4 months. There is more to the subject then I can write here, so here briefly is my observation.

Low ES/SD is about consistent ignition Percentage of case fill doesn't impact ignition. Doesn't impact es-Sd

Use high end brass eliminates a lot of issues.
Sorting brass and primers has little to no impact on ES/SD
Anneal-trim every time, (while I mandrel, have not noted impact ES/SD
Bullet of consistent weight & bearing surface
Measure powder to .02 (V4 or SuoerTrickler make this easy)
Find right powder - primer combo.
For PRC changing from fed 215 to 210 primer SD when from 26 to 4 over 10 shot strings

with PRC find a node at least .4 grains wide with little velocity change.

Hope this helps and doesn't add to the confusion.

Seems like the first two items are in conflict. Do you think their QC is better than yours, are they sprinkling it with magic fairy dust or something else?

 

[Ronald W Schaefer]

What i dont understand is when i am shooting an OCW Test and the load with the smalles ES and SD shoots the worst. And another load with like a 15-20 SD shoots under 1/2"

Man, I thought that was just me. I have that happen every time I work up a load for a new rifle. There is always one load that shoots lights out but the math sucks and another that is single digit ES/SD and it shoots meh. I (usually) eventually come upon the load that has both and that's what I Pick, but I've often wondered about that. I use a technique taught me by a benchrest competition shooting gunsmith about three years ago, (after I had already been loading about 45 yrs). Start with a powder load that gives the highest velocity at about a 95% loading density for the class/weight of bullets you plan to use. Load the same load with several different bullets in the weight class/end use intended as you can. Keep the best preforming bullet and then work up all the other factors. He says about 70% of the time the best bullet during this "cull" test will ultimately yield the best end results. He says the most important factor is finding the bullet your rig likes best, then tweaking the other load factors. I have had great results with that method and saved a lot of time and powder...though it does lead to a lot of unused bullets laying around.

 

[RegionRat]

Your gunsmith was a wise man...