Question re headspace - Do I resize brand new brass

Fusilier

Fusilier

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I am about to begin reloading .308 Win for my savage (Stevens) bolt rifle. I'm not hunting the rifle but trying to tune it for precision target shooting (I'm aware of the limitations of the basic rifle but let's not spend time on that here).

I bought some brand new Lapua brass. The headspace dimensions on this brass is a touch shorter than the brass from some comercial ammo I've already fired once in this particular rifle. I.E. the fireformed comercial brass has a slightly longer headspace dimension (using a RCBS Precision Mic) than the pristine unfired Lapua brass.

So my question is, do I full length resize this brand new brass before the first time I reload it or do I load it as is and accept a possible reduction in accuracy until it is fireformed in my rifle and then neck sized for the second reload?

Any thoughts or suggestions are welcome.

Cheers,
Fusilier
 
Fusilier said:
I am about to begin reloading .308 Win for my savage (Stevens) bolt rifle. I'm not hunting the rifle but trying to tune it for precision target shooting (I'm aware of the limitations of the basic rifle but let's not spend time on that here).

I bought some brand new Lapua brass. The headspace dimensions on this brass is a touch shorter than the brass from some comercial ammo I've already fired once in this particular rifle. I.E. the fireformed comercial brass has a slightly longer headspace dimension (using a RCBS Precision Mic) than the pristine unfired Lapua brass.

So my question is, do I full length resize this brand new brass before the first time I reload it or do I load it as is and accept a possible reduction in accuracy until it is fireformed in my rifle and then neck sized for the second reload?

Any thoughts or suggestions are welcome.

Cheers,
Fusilier
Click to expand...



Try each brass to see if it fits without the extra working of full length sizing when not needed.If the brass all fit , then neck size the brass only to round out the neck.
 
Not likely that much would need to be done with Lapua brass. If any necks are out of round from being banged around during shipping, you might necksize them.
 
Definitely and officially: Do not resize new Lapua brass. If your other fired brass has headspace longer than the new Lapua brass, have the rifle headspace checked. Call if you have questions.

Regards,
Peter Dobson
Hirsch Precision Inc.
 
PS, odds are there will be no reduction in accuracy with new brass. It may produce your best accuracy, contrary to some postings by "experts" on this site.
 
I don't want to enter this "expert" class, but just a way of getting perfect brass. If your rifle is a bit long for the brass, load a very light charge of a faster powder and put in a lead bullet, that is far enough out to hit the rifling, hard. This will hold the case hard against the bolt face. When fired, the case will perfectly fit the chamber. Presto, no more excessive head space! Just neck size from then on, or as they say, kiss the shoulder, and the brass should last a long time.
 
peterdobson said:
PS, odds are there will be no reduction in accuracy with new brass. It may produce your best accuracy, contrary to some postings by "experts" on this site.
Click to expand...
As Peter stated,

Some of my best groups were with virgin Lapua brass in my 6BR. I now bump my shoulders back .0015 after firing.
 
All new brass needs to be checked for length, trimmed if required(chamfered and deburred) and sized, no matter who made it.
"...fireformed comercial brass has a slightly longer..." It would. It'll stretch most on the first few firings. Cartridges do not have headspace though. Headspace is a manufacuring tolerance only.
 
Quote "Cartridges do not have headspace though. Headspace is a manufacuring tolerance only."
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The thread was about the 308 and the 308 headspaces on the shoulder. Therefore, the length of the cartridge from the base to the shoulder is as much a part of the headspace, as is the length of the chamber.
If the rifle chamber is a bit on the long side, from maufacture or wear, or both, ammunition on the short side of manufacturing tolerance, may have excessive headspace.
Lengthening the case, as I described, will fix the problem, with the cases so lengthened.
 
Jamming a bullet into the lands in the hope it will stop forward movement of the case when struck by the firing pin is a common misconception.

Load them up and shoot. I would suggest you use only a small lot of that brass until you swap the barrel, say 50-60.
 
peterdobson said:
PS, odds are there will be no reduction in accuracy with new brass. It may produce your best accuracy, contrary to some postings by "experts" on this site.
Click to expand...

If you think about it, Peter is right. Lapua brass is very uniform out of the box, so each cartridge case expands exactly the same amount on the first firing, which equals uniformity. Once fired, the brass has stretched, it may need to be trimmed, meaning there is now an increased variation of weight between each case which relates to volume, and each fired case will only be as concentric as the chamber and bolt face.

What happens from here on in is determined by how anal you are with your case prep and shooting technique. If each cartridge is indexed in to chamber exactly the same way for each subsequent shot, if the shoulder and neck are annealed with each firing, if the shoulder is only bumped back enough to assure easy chambering, if the neck is only sized enough to grip the bullet for a uniform pull weight, even a mediocre rifle can shoot surprisingly well.
 
The easiest way is to have to head stamp oriented to 12 o'clock then draw a line with a magic marker on the side of the case so that it can be visible from the top. If each cartridge is oriented in this fashion, should the line be lost during the case cleaning or annealing procedure, you still know how that case should be oriented in the chamber and the line replaced.

This is only followed by the most anal of shooters, and if your chamber is concentric is of little value.
 
On any brand of new brass, the necks usually aren't very concentric out of the box. Many also have dented mouths (even Lapua). I run new brass over a mandrel to straighten things out before loading them. Re-sizing isn't necessary.
 
Common situation with factory chambers - they can be on the long side of SAAMI spec. Nothing wrong with that as the factory ensures ALL ammo will fit no problem. Brass can be sized to the small side of SAAMI spec. Again, no biggie as it always fits.

The most important firing of any brass is that first high pressure bang. If the brass is overly undersized, the case may stretch the web area which can weaken the brass.

If the brass is 2 to 3 thou shorter, no biggie. If you are in the 5 to 10 thou range, you can stretch the web area and it will be inconsistent. This will apply to ANY brand of brass in any chambering.

You can measure your new brass so you already are ahead of the game. If only a few thou shorter, no worries. Size the necks to get rid of any dents and go work up your loads.

If you couldn't the easiest way is to chamber a primed but empty case. In a safe manner, pop that primer and see what happens. Sometimes the case is so much shorter that the primer will not ignite or have a very light dent if it did.

That is a sure sign that full pressure firing will stress the web area. No big deal if you are firing and forgetting the case. But a reloader wanting max case life, you may want to take care.

If really short, you would expand the neck to say 33cal, then neck back to 308 forming a secondary shoulder. This shoulder is located so you feel slight resistance chambering. Fireforming with a light load of pistol powder and cornmeal/cream of wheat will gently move that shoulder into the right headspace with no stress of the web area.

The other method of using the bullet jam method will also work but that gets expensive and puts wear on the barrel.

With properly fireformed brass, neck sizing and min moving of the shoulder will lead to very long case life and best accuracy.

Enjoy your stevens. Varget behind 155gr Amax, Bergers or Lapua are going to keep you smiling every time you go to the range. Just keep that barrel from getting too hot or groups will go south in a big hurry.

Jerry
 
Boomer said:
The easiest way is to have to head stamp oriented to 12 o'clock then draw a line with a magic marker on the side of the case so that it can be visible from the top. If each cartridge is oriented in this fashion, should the line be lost during the case cleaning or annealing procedure, you still know how that case should be oriented in the chamber and the line replaced.
Click to expand...

Thanks for the info...
 
The discussion and information is great. Very much appreciated by one who is just getting into rifle reloading.

Here are some of my numbers in case anyone is interested.

I measured headspace on brass from some commercial hunting ammo that I fired in my rifle. The average headspace measured out to 1.6295, only a half a thou shorter than the standard ANSI 1.6300 to 1.6400 quoted for the .308 Winchester. Now when I measure some of the new Lapua brass, it comes in at around 1.6264 or about 3 thou shorter than the commercial brass already fired in my rifle.

These are the numbers I'm looking at and I'm trying to make sense of it.

I will likely still have to run the Lapua brass (or some if it) through a neck sizer at least to round out the mouths. Some of it got a little banged up in those 100 round bulk boxes they come in.

Peter Dobson: Thanks for your toughts. I bought my AR off of you about 6 years or so ago. Just wanted to say hi.

Cheers,
Fusilier
 
Your getting caught up in the tolerance game. Rifle manufacturers must produce chambers within certain tolerances, including the headspace dimension. Brass manufacturers must also do so, but to a lesser dimension, to ensure that all brass will chamber in all rifles, yet not be too sloppy to fire properly.
I dont have my reloading manual handy, but the numbers you quote are likely the chamber tolerance. Looks like you have a tight chamber, from the dimension of your fired brass. Your Lapua is only 3 thou less, ensuring a snug fit inside the chamber. Resizing can only make the brass smaller, so dont bother unless you need to form the mouths, in which case a minimal partial resize, or neck size, is in order.
Fire away, and let us know how you do!
 
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