223 case headspace

[Koda]

My Redding full length sizing die is resulting in the case headspace below SAAMI spec as low as 1.453".
(SAAMI spec is 1.4666 max to 1.4596 min)

I did not notice this when I started working on a load for 223 because I knew I wanted to FL size for a semi auto and not bother with shoulder bumping, I assumed a full length sizing die would not be made to produce out of spec brass. Only out of curiosity I checked some samples and found this....

I did a ladder test found a charge and reloaded another batch and confirmed the recipe. Today I wanted to load some rounds to that recipe using some resized cases and some new virgin brass... the virgin brass is in spec, I was going to resize them anyways to make everything consistent and the same so I checked them and found the difference so I checked the saami spec.

So now Im wondering what to do? Is it bad to run out of tolerance on the small end? Or should I start over and start backing off the FL die to get the correct case headspace?

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[arrowshooter]

A big difference between Saami and Hornady is where they measure the shoulder at. I am bumping my .223 .003" - .004" and end up at 1.449". I would base your measurements off of cases fired from your chamber and adjust the die accordingly.

 

[Koda]

A big difference between Saami and Hornady is where they measure the shoulder at. I am bumping my .223 .003" - .004" and end up at 1.449". I would base your measurements off of cases fired from your chamber and adjust the die accordingly.

Im assuming the Hornady gauge measures the same datum point saami is?

I was wanting to avoid shoulder bumping since Im loading for a semi auto. What Im going to check now is if cam over is affecting this vs setting the die so it just firmly touches the ram per Redding instruction.

The Redding dies are supposed to assure it will fit a minimum chamber, so maybe it makes sense the result is under saami spec and it doesnt hurt anything?

 

[arrowshooter]

Im assuming the Hornady gauge measures the same datum point saami is?

I was wanting to avoid shoulder bumping since Im loading for a semi auto. What Im going to check now is if cam over is affecting this vs setting the die so it just firmly touches the ram per Redding instruction.

The Redding dies are supposed to assure it will fit a minimum chamber, so maybe it makes sense the result is under saami spec and it doesnt hurt anything?

I do not know the exact difference between the two, but I know that each Hornady insert is made to fit a variety of cases.

Maybe I have learned backwards, but it is suggested that semi-autos need a bit of a bump to assist in feeding.

I have found that factory ammo is undersized to make sure there are no feeding issues in any chamber, so I am sure it will not hurt anything.

How are your measurements on your fired brass with the primer removed?

 

[Koda]

How are your measurements on your fired brass with the primer removed?

1.463"....

I also sized one case without cam over (per Redding instruction) and it comes out at 1.455" which is .005" smaller than saami minimum spec. Im thinking its ok to use smaller case headspace just not longer. Its not ideal for the case to grow .005" but Im not seeing it a safety issue? I was getting good groups with my recipe.

 

[Koda]

...so basically if my fireformed brass (chamber) is 1.463" and my FL sized brass comes out at 1.455" thats bumping the shoulder .008".
That should assure reliable feeding in a semi auto. Its odd that the Redding die would produce a measurement under the saami minimum but its possible that manufacturing tolerances are stacking up here and Im not seeing a safety issue with it being .005" too small.... ?

 

[dangerranger60]

By running below min headspace, you will be working your brass harder than it has to. If you are only loading for one gun, and your gun shoots this load well, it is not hurting anything but the brass. You will get a couple less reloadings from it.
If this is a load you are running in several guns I would not change, but if this is only for one gun it would not hurt to extend your die adjustment till you are at or just over min length.
223 is one case I pick up so much at the range that tossing brass is not a problem.
If it was hornet brass, I want every loading I can get from it! Good Luck DR

 

[arrowshooter]

One thing that may help to ease your mind is picking up a Slotted Sheridan Head Space Gauge. These are cut to minimum Saami specs and are supposed to be extremely accurate. It will tell you exactly where you are.

https://sheridanengineering.com/product/223-rem-ammunition-gauge/

 

[Koda]

By running below min headspace, you will be working your brass harder than it has to. If you are only loading for one gun, and your gun shoots this load well, it is not hurting anything but the brass. You will get a couple less reloadings from it.
If this is a load you are running in several guns I would not change, but if this is only for one gun it would not hurt to extend your die adjustment till you are at or just over min length.
223 is one case I pick up so much at the range that tossing brass is not a problem.
If it was hornet brass, I want every loading I can get from it! Good Luck DR

Brass life is a very good point. This is my only 223 so it wouldnt hurt to maximize brass life. I think at some point I will test backing off the die to just over min length, for now I will finish this recipe off as is rather than start over, Im not certain how much .005"-.006" shoulder bump will affect accuracy and velocity.....

 

[Koda]

One thing that may help to ease your mind is picking up a Slotted Sheridan Head Space Gauge. These are cut to minimum Saami specs and are supposed to be extremely accurate. It will tell you exactly where you are.

https://sheridanengineering.com/product/223-rem-ammunition-gauge/

Im not convinced I need this but the visual reference of the slotted version is probably worth the price.....

 

[Pepe-lepew]

0.008" of clearance is too much. It is flirting with case head separations if you plan to reuse this brass much. 0.013" will case head separate on the 2nd reload. I know this by personal experience.

It isn't uncommon for dies to oversize. My Hornady die is similar. The best solution is the Redding Competition shell holder set. It allows you to use oversized shell holders to set the head clearance you need, while using the repeatability of cam over on your press.

I use the 0.006" oversize Redding shell holder for all my 223 brass. It gives me 0.002" clearance on my tightest 223 chamber. My chambers don't vary much, only at most a couple thousandths.

 

[Koda]

0.008" of clearance is too much. It is flirting with case head separations if you plan to reuse this brass much. 0.013" will case head separate on the 2nd reload. I know this by personal experience.

It isn't uncommon for dies to oversize. My Hornady die is similar. The best solution is the Redding Competition shell holder set. It allows you to use oversized shell holders to set the head clearance you need, while using the repeatability of cam over on your press.

I use the 0.006" oversize Redding shell holder for all my 223 brass. It gives me 0.002" clearance on my tightest 223 chamber. My chambers don't vary much, only at most a couple thousandths.

If .008" is a safety issue then why do they sell dies out of spec?

I'm totally find shoulder bumping FL dies if its part of the normal process but my understanding is shoulder bumping is an advanced technique thats not necessary for general reloading for semi autos and general accuracy....

 

[Pepe-lepew]

Case head seperations are a reliability issue, not a safety issue. Nothing typically catastrophic happens. Many times is is found by most the case is still stuck in the chamber or finding cracks in the case wall when prepping brass.

Modern rifles are mostly near minimum headspace. I suspect die manufactures error on the side of minimum to ensure enough sizing to fit a minimum chamber. It also is easier for them to blame the brass on case head failure than a sized case not fitting in a chamber on something else than their die. I agree dies should not oversize past SAAMI minimum case shoulder dimension. You would think in modern manufacturing, hitting plus or minus 0.0005" would be easily doable.

 

[DizzyJ]

Bump the shoulder back .003" from what a fired case is in that gun. This is for a semi-auto. Make notes.

For a bolt gun, bump the shoulder .001"-.002"

You shouldn't have to cam over on the die.

The die manufacturers tell you to set it up that way so it'll be sure to chamber reliably. The flip side is you're overworking and stretching your brass excessively.

If you want to cam over and still get the correct headspace, get a set of Redding competition shell holders and you can cam lever or "kiss" the shell holder and still get the correct headspace.

 

[Koda]

Bump the shoulder back .003" from what a fired case is in that gun. This is for a semi-auto. Make notes.

For a bolt gun, bump the shoulder .001"-.002"

You shouldn't have to cam over on the die.

The die manufacturers tell you to set it up that way so it'll be sure to chamber reliably. The flip side is you're overworking and stretching your brass excessively.

If you want to cam over and still get the correct headspace, get a set of Redding competition shell holders and you can cam lever or "kiss" the shell holder and still get the correct headspace.

it sounds like then that shoulder bumping is the normal process for full length sizing, regardless of action.

 

[DizzyJ]

it sounds like then that shoulder bumping is the normal process for full length sizing, regardless of action.

I suppose you could give it "zero" bump if you really wanted?

Generally it's the "amount of bump" you give it depending on the platform and purpose.

 

[Koda]

I suppose you could give it "zero" bump if you really wanted?

Generally it's the "amount of bump" you give it depending on the platform and purpose.

I'm not certain what zero bump would be good for.... at least in a semi auto.
My understanding was that traditional full length sizing was set by the die and no bumping was required. Dies are made to fit all chambers as well as ideal for semi autos.
But I'm still fairly new to this and will adapt as I learn more as I go, no problem shoulder bumping for a semi auto. Maybe what I will do here is load this next batch bumping the shoulder .003" and if it affects my accuracy or velocity I can work a fine tuned ladder test from there to finish my recipe.

 

[DizzyJ]

I'm not certain what zero bump would be good for.... at least in a semi auto.

It would be a very bad idea for a semi auto.

 

[DizzyJ]

Some chambers are shorter than others.

Some shell holders are slightly taller than others.

Stack up tolerances in the wrong direction and you'll have ammo that doesn't chamber. The die manufacturers know this and err on the side of over sizing in order to make sure the ammo will reliably chamber. The result is usually over worked brass with shoulders pushed too far back.

 

[Koda]

Some chambers are shorter than others.

Some shell holders are slightly taller than others.

Stack up tolerances in the wrong direction and you'll have ammo that doesn't chamber. The die manufacturers know this and err on the side of over sizing in order to make sure the ammo will reliably chamber. The result is usually over worked brass with shoulders pushed too far back.

Today was a good discovery then. Im glad I went slow...
Ill work shoulder bumping into my recipe, and for all rifles as a normal part of full length sizing. The cool thing is I happen to have one of those Forster lock rings with dial marks on the way with my new sonic cleaner.