SD/ES New Brass

[haisardao]

I have a question and would appreciate any input you could give. How much weight do
You put into SD/ES when developing a load with new brass?
My process for new brass involves the following, FL size, expand with a mandrel, and do all the jazz to primer pockets, flash hole etc. I weight all my charges to the .02 that my scale allows, and usually seat bullets .0.15-.020 off the lands. neck tension is usually .002.
Most of the time I get ES in the 20s low 30s, and SDs 8-12.
Is this what most people see with new brass, followed by improvement once fire formed?
Thanks
H

 

[RegionRat]

This is another one of those "it depends" answers.

Many times, a recipe is going to have a low SD/ES from virgin brass or formed brass, but sometimes there is a slight improvement from formed brass. You will just have to try.

Suppose the fired brass is tried and you are unhappy, then you will likely be able to do better with a change in the recipe be it from a difference in neck tension, or a recipe change for example.

If you end up down the road with a change that gives you a better velocity stat, then go back and try virgin brass and you will likely find it is also better there too. YMMV

 

[Mikecr]

The ES/SD could also be lower with new brass -vs- fully fire formed.
The issue is that it's different.

It's better to fire form to stable case dimensions before moving into powder development.
So while Fire forming you can do full coarse seating testing, and you can do some primer swapping.
Can get everything with your rests and shooting system right.

 

[FEENIX]

The ES/SD could also be lower with new brass -vs- fully fire formed.
The issue is that it's different.

It's better to fire form to stable case dimensions before moving into powder development.
So while Fire forming you can do full coarse seating testing, and you can do some primer swapping.
Can get everything with your rests and shooting system right.

This!

 

[FEENIX]

This is another one of those "it depends" answers.

Many times, a recipe is going to have a low SD/ES from virgin brass or formed brass, but sometimes there is a slight improvement from formed brass. You will just have to try.

Suppose the fired brass is tried and you are unhappy, then you will likely be able to do better with a change in the recipe be it from a difference in neck tension, or a recipe change for example.

If you end up down the road with a change that gives you a better velocity stat, then go back and try virgin brass and you will likely find it is also better there too. YMMV

This!

 

[MagnumManiac]

I will answer your question with none, you're wasting your time.
The issue is that fired brass takes on different dimensions and alters the capacity, this often raises pressure with the same loads previously used in new brass. In fact, I don't even run tests for powder in brass until it has had 3 firings so that it is becoming stable, I also move the brass as little as possible and order dies to suit those dimensions, especially the neck, which I have honed to suit, even in my hunting rifles.

Cheers.

 

[haisardao]

I will answer your question with none, you're wasting your time.
The issue is that fired brass takes on different dimensions and alters the capacity, this often raises pressure with the same loads previously used in new brass. In fact, I don't even run tests for powder in brass until it has had 3 firings so that it is becoming stable, I also move the brass as little as possible and order dies to suit those dimensions, especially the neck, which I have honed to suit, even in my hunting rifles.

Cheers.

Thanks. So when you are developing a hunting load, my intended use, if they shoot to your expectations you settle to that load and after a few firings play around to improve your ES/SD?

 

[MagnumManiac]

Well, I don't take ES into consideration until I am shooting beyond 600… but yes, I fiddle with powder to get best ES. It must be understood though that I get best seating depth first, then shoot for powder at 600, where elevation tells me if the powder is correct, this almost negates the need for using the chrono to work out ES.

Cheers.

 

[biednick]

It depends on how much brass you have. If you have 200 pieces of brass it makes sense to fire it all before really worrying about fine tuning your load. You need to get some rounds down the barrel so it settles down anyway. I buy 500-1000 pieces of brass for every gun. If I wait until I fire it l I might burn 1/3 of my barrel life before I start load development, not to mention the hundreds of dollars in components that would cost me. I find a good load with my new brass and tweak it tweak it as needed with each new batch. I usually find I need to make small changes every 500-1000 rounds anyway, regardless of whether the brass has been fired one time or ten.

 

[haisardao]

It depends on how much brass you have. If you have 200 pieces of brass it makes sense to fire it all before really worrying about fine tuning your load. You need to get some rounds down the barrel so it settles down anyway. I buy 500-1000 pieces of brass for every gun. If I wait until I fire it l I might burn 1/3 of my barrel life before I start load development, not to mention the hundreds of dollars in components that would cost me. I find a good load with my new brass and tweak it tweak it as needed with each new batch. I usually find I need to make small changes every 500-1000 rounds anyway, regardless of whether the brass has been fired one time or ten.

Thanks, makes sense.

 

[WYO300RUM]

The ES/SD could also be lower with new brass -vs- fully fire formed.
The issue is that it's different.

It's better to fire form to stable case dimensions before moving into powder development.
So while Fire forming you can do full coarse seating testing, and you can do some primer swapping.
Can get everything with your rests and shooting system right.

I don't know the reason but most times I get lower ES and SD with new brass than with once or twice fired . Same exact load. I think I'm going to stop chronographing first loads. I know I shouldn't any way. Just fire form them. Hard to change habits after 47 years. I just started using ADG and Lapua about 6 years ago. What a difference.

 

[WYO300RUM]

I will answer your question with none, you're wasting your time.
The issue is that fired brass takes on different dimensions and alters the capacity, this often raises pressure with the same loads previously used in new brass. In fact, I don't even run tests for powder in brass until it has had 3 firings so that it is becoming stable, I also move the brass as little as possible and order dies to suit those dimensions, especially the neck, which I have honed to suit, even in my hunting rifles.

Cheers.

 

[rooster740]

My ES in 223 with new lapua brass is around 50fps using cfe223 25gr. And 75 Eld-m. Vs 8-10fps with twice fired brass
In 6br. And varget it's ES of 25ish fps new alpha brass vs 6-8fps twice fired.

30 Sherman fire forming is es 20-30fps and es of8-10fps with twice fired.
This is pretty consistent

Yesterday I broke in a 6.5prc barrel it's a proof prefit.
(Carson if you are lurking Bella won it at the finale)
I am a big fan of Lilja barrels!

My first 5 rounds had es of 106fps. On new lapua brass

Second 5 rounds es40fps

Third 5 rounds es of mid 14fps.

Forth 5 rounds es of 12fps.

Bug holes.

Swapped to an 8 pound keg of same powder from 2019 that gave me hell then and everything else was identical and lost 80fps and es of 60-80fps.

At the end I had a 1" 40 shot group with about 5 fliers to make it1.5"

 

[QuietTexan]

Why are you sizing new brass?

If your die is set up to actually do anything to new cases, then it's set way too short.

At most run a mandrel through the neck if they're tight. If not just load them how they are.