Fire forming fresh brass

[jlorenzo]

In a 223 would it make sense to use cheap bullets on fresh Lapua brass on the first firing? I have been hearing around forums that your brass doesn't fully fire form until the 2nd or 3rd firing (or something like that, not quite sure).
I have also seen pictures of someone that loaded up what looked like playdo, so as not to waste expensive bullets.
Can anyone comment on this? Should I just shoot the fresh brass with the intended bullet and powder and roll with it?
Can I start load dev with unfired Lapua brass?
Thanks for your help.

 

[GLShooter]

Ideally you wouldn't use new brass for your load development. It's not what you will have after things are shot. Capacity changes as does the ductility if the case.

Greg

 

[RegionRat]

It depends on the game you are playing.

Some folks account for the difference in performance, and run their first firing in Club Matches and some of them win while doing this in Mid Range matches.

They know they will get a difference after the first cycle, but when the batch size is large enough, and they have lots of experience, they know how much difference to expect on the second cycle. No reason to throw the first cycle away.

 

[jepp2]

I have been hearing around forums that your brass doesn't fully fire form until the 2nd or 3rd firing (or something like that,

Without knowing more about your:
- sizing practices
- reloading skill level
- shooting proficiency
it is a guess at answering your question in a meaningful way.

When I receive new brass, I measure the case head to datum and compare that with the bolt contact length in the rifle I intend to shoot it in. Unless the new brass is longer than bolt contact, I do not FL size the brass. But it tells me how close to my chamber size the new brass is.

If you full length size your brass after every firing, depending on how you setup your sizing die, it will never reach chamber length. The 2, 3, or 4 firings are the number required to make your brass long enough so you have bolt contact when chambering the round. And this means you are neck sizing, not full length sizing.

I've fireformed thousands of rounds for 20 Bobcat and 223AI where I am blowing the shoulder out and the case is changing dimension-ally to a much greater extent. And my experience as well as others is the accuracy is outstanding during this step.

Unless you anneal after every firing, your case neck will be work hardening after each firing/sizing cycle. Neck tension can affect accuracy.

Just trying to add some additional detail to address what you are asking.

 

[jlorenzo]

Without knowing more about your:
- sizing practices
- reloading skill level
- shooting proficiency
it is a guess at answering your question in a meaningful way.

When I receive new brass, I measure the case head to datum and compare that with the bolt contact length in the rifle I intend to shoot it in. Unless the new brass is longer than bolt contact, I do not FL size the brass. But it tells me how close to my chamber size the new brass is.

If you full length size your brass after every firing, depending on how you setup your sizing die, it will never reach chamber length. The 2, 3, or 4 firings are the number required to make your brass long enough so you have bolt contact when chambering the round. And this means you are neck sizing, not full length sizing.

I've fireformed thousands of rounds for 20 Bobcat and 223AI where I am blowing the shoulder out and the case is changing dimension-ally to a much greater extent. And my experience as well as others is the accuracy is outstanding during this step.

Unless you anneal after every firing, your case neck will be work hardening after each firing/sizing cycle. Neck tension can affect accuracy.

Just trying to add some additional detail to address what you are asking.

Would you be able to find the datum using a Hornady headspace comparator or is something else needed? Not sure if the datum is a precise spot on the shoulder or just the shoulder itself where it contacts the chamber. I have only been full length sizing with a Hornady custom die, looking into a mandrel or possibly a bushing but leaning towards mandrel. I do not currently anneal but would like to once funds allow. I will admit typically I try and keep things broadly simple.
As of now I fire a round factory round (I use xm193 LC brass in my .223 so far) then set the sizing die to bump the shoulder back around .002" and call it good. I do not change that setting for the life of the brass.
I am looking to get away from the expander ball in the FL sizing die and work on neck tension. That is all relatively new to me.

Looking at possibly something like this, although it still isn't 100% clear to me if it has a removable mandrel or it is just the one size. I am open to suggestions.

.223 Rem / 5.56 NATO Sizing Decapping Die | Mighty Armory

The .223, 5.56 Full Length Sizing Die offers concentricity and consistency. Built to last over a million cycles. Mighty Armory Reloading Dies for Precision.

www.mightyarmory.com

I am just a hobbyist and will be shooting some club and local matches, nothing super competitive.

My plan now once a new rifle is received, is to chamber the fresh brass to see if the bolt will close (possibly removing firing pin, etc). If it closes easily I can just load and go? If it doesn't I should FL size?

*I should add I would like to have this all figured out and come up with a solid strategy before diving in buying Lapua brass.

 

[jepp2]

Would you be able to find the datum using a Hornady headspace comparator

Yes. It is a relative measurement, but that is enough.

As of now I fire a round factory round (I use xm193 LC brass in my .223 so far) then set the sizing die to bump the shoulder back around .002" and call it good.

That might be Ok, but if after the first firing the brass still is much shorter than the chamber, you are making it 0.002" shorter. What did it measure before firing (which will give you an idea of how much it grew on a single firing)? As you size brass it moves the shoulder forward (longer) by squeezing in the walls before the shoulder is set back by your sizing die. You can use this to try and find your chamber length. Size some without setting the shoulder back, measure them and try them in your rifle.

My plan now once a new rifle is received, is to chamber the fresh brass to see if the bolt will close (possibly removing firing pin, etc). If it closes easily I can just load and go?

Good plan. Measure it so you know the case head to datum length. I would run something (expender mandrel, or die resizing button) to make the case necks round and the proper size. Then I would lightly chamfer the inside of the case neck to avoid scratches on the bullet jacket.

 

[Old Navy]

Should I just shoot the fresh brass with the intended bullet and powder and roll with it?
Can I start load dev with unfired Lapua brass?
Thanks for your help.
Yes and Yes! I jam mine about .010" the first loading to make sure the base is back against the bolt.