Low ES=Best Group

[Rhovee]

I asked this questions in another thread but didn't want to high jack. I have usually done load development only focusing on groups. It seems that the ES of those groups are always pretty low. My question is, does the lowest ES always pan out to a good group? Like if you load rounds and find a good node, does it always end up panning out after you adjust seating depth? Reason i ask is that some of the hot loads that i have done, don't work out that way. They will have an ES of 4 and shoot 1.25. Then i'll lower powder, shoot a .3 and have an ES of 14....

 

[dok7mm]

How many rounds are you shooting to get your numbers? Five is a minimum, ten is much better. What chrono are you using? How are you setting neck tension? How are you weighing powder? These will all make a difference.

The simple answer is no, unless you are in a node, when you stretch out to longer ranges. Some claim to have high sd & es and shoot tiny groups at distance. I have not found this to be true with my rifles. A good ladder run at 3-400 yds will separate the wheat from the chaff, so to speak.

 

[Kansaswoodguy]

I look for single digit SD I'm not sure I couldn't load develop with a chronograph and dirt pile and skip the paper completely which would eliminate the loose nut behind the trigger.

 

[Rhovee]

I was shooting 3 shot groups to see what the average was. That's was just to see pressure and groups. I use a hornady automatic thrower and scale. Not to impressed with it. But do double check everything. I do anneal brass and use a neck bushing. Neck tension is 1 thou. I did find a es of 6 and sd of 3.4 in my 28 using Norma brass and N570. Still need to verify es over 10 shots, which I have loaded just haven't shot yet. I just don't have the time and space to run a 3-500 yard ladder. I have always loaded with doing seating first and then powder. But I did realize that there was a node between 3020-3040. This is for a new rifle and this time around I would like to find the node and stay there. I did shoot 63 for an average of 3174 and 63.5 for 3080. But 63.5 shot like garbage. 63.5 was 1/2". I was really surprised to see .5 grains change very little fps and close the groups by more than half. Seating depth was the same.

 

[dok7mm]

It sounds like you are getting close. I usually start at .020" off and do powder charge. But I do a 300 yd ladder and it puts me on to two nodes with 9-10 shots. You can do a 200 yd ladder, w/ .5 increments. They'll be close together, so you need to plot each shot on your notes to keep them straight.

Exact same neck tension and accurate powder weighing are soooo darned important in our consistent accuracy game, but often are hard to attain. Do you have access to an annealer? Work hardening is hardly ever consistent from one case to the next, especially after a few firings, and groups suffer. I would bet it's little things combined that have you scratching your head. A small variance in resizing, powder charge, run-out, neck tension, etc, all add up and you have to figure it out. I wish you luck, but examine each facet individually and you'll solve it.

 

[Alex Wheeler]

Almost never. Once your ES is under 20 stop looking at it.

 

[Rhovee]

I just got thrown for a big loop and haven't ran into this before. 63.5 of RL 26 shot a .4 group last weekend. Went back out and barrel sped up and was shooting 50 fps faster which was 3220. So dropped the powder 1.5 grains to 62 and was still at 3200 with an es of 10. 3198-3202-3208. Grouping wasn't great. Last session 63.5 shot 3078 which was the .4 group. Not sure if I should drop down tell I get into 3180 or adjust 62 that's right at 3200 and mess with seating depth. Group was two same hole with one horizontal right about 1.15"

 

[J E Custom]

I asked this questions in another thread but didn't want to high jack. I have usually done load development only focusing on groups. It seems that the ES of those groups are always pretty low. My question is, does the lowest ES always pan out to a good group? Like if you load rounds and find a good node, does it always end up panning out after you adjust seating depth? Reason i ask is that some of the hot loads that i have done, don't work out that way. They will have an ES of 4 and shoot 1.25. Then i'll lower powder, shoot a .3 and have an ES of 14....

What low SDs And ESs mean to me is that I have a good powder, primer combination for the bullet weight being used. Accuracy can be achieved by finding the bullet In this weight that the barrel likes. Experimenting with seating depth may improve this accuracy even more.

So if you have good SDs and ESs work on the bullet and don't change the powder primer combination. If you have good groups but not SDs And ESs, work on the primer powder combo and increase/decrease the powder to achieve the same velocity with that bullet that you were getting with the accuracy load.

J E CUSTOM

 

[Rhovee]

So far I hit bolt lift at 63.6.
62.8 average 3204 es 10
62.4 average 3198 es 14
62 average 3203 es 9.

Thinking about choosing the lower powder charge and adjusting seating depth to see if it irons out.

 

[dougduey]

Looks like you're on a velocity "flat spot" which is a node. Look up the 10 round load development technique on the 6.5 Guys website. It's a pretty good method for finding an accurate load. You may have to tweak the seating depth to fine tune things. It's just another way to skin the load development cat!!

 

[Rich Coyle]

In Brian's book he said they discovered the best groups were fired with .003" neck tension. I made life easy for myself and had full length dies made by Forester with the neck size I want for neck turned cases.

 

[Alex Wheeler]

In Brian's book he said they discovered the best groups were fired with .003" neck tension. I made life easy for myself and had full length dies made by Forester with the neck size I want for neck turned cases.

One of the most detrimental things you can do is assume another"s results will duplicate in your rifle. You should test everything in your barrel. .003" is a very good place to start though.

 

[Deleted member 46119]

@Alex Wheeler has that correct. However. ..

Depending on the cartridge, type of load and type of shooting, .002 to .004 is a good starting point.

Meaning the ID of the case mouth is less than the bullet by that amount.

The actual "tension" is a more complicated thing involving stretch to yield, clamping forces and things I don't know how to describe.

As I understand it. The idea behind .003 "tension" is to avoid yield. Yield "works" the brass changing hardness. Changing hardness changes clamping forces and release consistency.

A .003 "tension" might not be perfect and if used for any hunting where the ammo could receive rough handling more tension might be better.

Remember to anneal or your "tension" will change over time.

 

[Rich Coyle]

One of the most detrimental things you can do is assume another"s results will duplicate in your rifle. You should test everything in your barrel. .003" is a very good place to start though.

He said that was duplicated in multiple rifles.