Another head space question

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va_connoisseur

New member
I have a question(s) about headspace and what is too much. My .308 fired shells measure ~1.622 in, using the Hornady Comparator. To clarify, these are shells fired from my gun. When I full-length resized that brass, the measurement was ~1.605 in. Does that mean I bumped the shoulder 0.015?

Is that too much headspace/bump? Will head separation be possible? Are the shells safe?
 
You moved the shoulder back .017.

Yes, you will have a base crack at some point.

One time (new brass) is not dangerous.

When you hit X resizes at that rate, you will crack the head.

If it just cracks, you are ok, if it blows off, then there will be a gas escape and that depends on how much as well as if the case head is supported.

What you want to avoid the issue, move your die up and shoot for .003 to start with.

Each case is a bit different in how it acts, you may or may not be able to hit the better .002.

I have had no head case cracks since I started to do the minimum bump back.

Large chamber military surplus rifles are the worst. Its not just the shoulder, its also the body. They also are usually unsupported heads.
 
Thanks for the feedback. I will pull all the bullets and save the powder. Even though these are one fired pieces of brass, not worth risking it.
 
Old timer advice:
Step 1: For bolt action rifles, size brass until you are comfortable with the amount of effort required to close the bolt on the sized case.
Step 2: You're done.
 
I have a question(s) about headspace and what is too much. My .308 fired shells measure ~1.622 in, using the Hornady Comparator. To clarify, these are shells fired from my gun. When I full-length resized that brass, the measurement was ~1.605 in. Does that mean I bumped the shoulder 0.015?

Is that too much headspace/bump? Will head separation be possible? Are the shells safe?
Click to expand...

It has nothing to do with me giving up because I measure before and again after. Had you measure the length of the case from the datum to the case head and found the case length from the datum to the case head was 1.622" you should have adjusted the die. If you sized a case and the die was adjusted to full length sized the case you should have raised the die .013". Had you raised the die .013" you would have .004" clearance between the case and chamber.

You can continue to repeat everything you hear and read like bump. case head space and throw in an occasional cam over but those are difficult habits to break.

.017"? In some circles of reloading that is some serious difference in length between a go-gage length chamber and a field reject length chamber. BUT! Not for me. I form cases; I form cases for short chambers and I form cases for long chambers. (again) I have one chamber that is .016" longer than a minimum length/full length case. That is the difference in length between a go-gage length chamber and a field reject length chamber. I add .014" to the length of the case between the datum and case head to get .002" clearance..

Try this: Loosen the lock ring and after loosing the lock ring screw the die down to the shell holder. After contacting the shell holder raise the die .013". I raise the die and make adjustments with a feeler gage, if you do not have a feeler gage use a dial caliper or a height gage. After making the adjustment secure the die to the press with the lock ring.

Raising the die prevents you from oversizing the case, some reloaders purchase Redding competition shell holders for about $40.00, a good feeler gage cost about $11.00 and is universal.

F. Guffey

Place the feeler gage between the top of the shell holder and bottom of the die with the ram up. This adjustment works with non cam over presses. Cam over presses bump at the top.
 
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Reloaders have been conditioned to repeat what they read and what they hear; again it is a difficult habit to get out of.

Reloaders have been conditioned to say the firing pin drives the case forward until the shoulder of the case contacts the shoulder of the chamber. And then one of them adds the part about the firing pin shortening the case from the shoulder of the case to the case head by as much as .005" and they say all of that happens before they hear the bang.


va_connoisseur, you should ask "What does this have to do with me".

Reloaders take short cuts, they go straight to case head separation with nothing before and or in-between. It is case head separation or nothing. Me? I have claimed there are times my shoulder does not move when the case Is fired. When the shoulder does not move forward the chance of case head separation is reduced. And then there is the 'on the other hand'. On the other hand when the case shoulder is against the shoulder of the chamber when the case fires the chance of stretching the case between the case head and case body is guaranteed.

One more time: I have fired 8MM57 ammo in one of my 8MM06 chambers, the difference in length between the 8MM57 and the 8MM06 is .127", meaning I had .127" clearance between the shoulder of the case and shoulder of the chamber; that is .65" more interesting than what Hatcher did, the shoulder on my cases did not move and the case did not stretch between the case head and case body. The case when ejected looked like an 8mm06 case with a very short neck.

F. Guffey
 
Mr Guffey: My compliments. You taught in a clear and understandable fashion. Well done.

va_ conn... You are trying to put it all together. That's good.

Whether technically correct or not,the term "headspace" gets applied to the rifle chamber and to the brass.
Its really only correctly applied to the rifle chamber.
The chamber is properly cut when it accepts a headspace "go" gauge and it does not accept a headspace "no go gauge". But the criteria for being worn out or at an unacceptable excessive headspace is the "field" headspace gauge.

IMO,I would not necessarily measure my brass with a comparator gauge and get concerned about my rifle headspace. Establish rifle headspace with a headspace gauge.

It is good handloading practice to minimize the "head clearance" between the ammo and the chamber.This minimizes case stretch and extends brass life.
Your Hornady tool will help.

If you have a bolt gun,your fired brass will give you a good starting point. Use your Hornady tool to measure about .002 change and then confirm it chambers easily in your rifle. Using Mr Guffey's suggested feeler gauge method is good. It beats turning the die "1/8 turn" etc. You have precise control.

Something to realize if your rifle is a semi-auto,even if your chamber is minimum headspace,your brass may stretch during cycling. Your Hornady tool may be misleading.
Generally,when loading for a semi-auto,more head clearance is required to ensure the rifle esily goes to full battery lockup before firing.A guideline might be .004 for an AR type and .006 for a Garand/M1A type.

Of course,I expect to get negative feedback.My source is the Precision Shooting Reloaders Hand Book,chapters on Reloading for Competition.,NRA HighPower,etc.
 
F. Guffey said:
Reloaders have been conditioned to repeat what they read and what they hear; again it is a difficult habit to get out of.

Reloaders have been conditioned to say the firing pin drives the case forward until the shoulder of the case contacts the shoulder of the chamber. And then one of them adds the part about the firing pin shortening the case from the shoulder of the case to the case head by as much as .005" and they say all of that happens before they hear the bang.


va_connoisseur, you should ask "What does this have to do with me".

Reloaders take short cuts, they go straight to case head separation with nothing before and or in-between. It is case head separation or nothing. Me? I have claimed there are times my shoulder does not move when the case Is fired. When the shoulder does not move forward the chance of case head separation is reduced. And then there is the 'on the other hand'. On the other hand when the case shoulder is against the shoulder of the chamber when the case fires the chance of stretching the case between the case head and case body is guaranteed.

One more time: I have fired 8MM57 ammo in one of my 8MM06 chambers, the difference in length between the 8MM57 and the 8MM06 is .127", meaning I had .127" clearance between the shoulder of the case and shoulder of the chamber; that is .65" more interesting than what Hatcher did, the shoulder on my cases did not move and the case did not stretch between the case head and case body. The case when ejected looked like an 8mm06 case with a very short neck.

F. Guffey
Click to expand...
Thanks for the feeler gauge technique, I never thought of that.

To boil it all down, are these cases safe or should I pull the bullets, save the powder and consider the cases a loss?

I genuinely appreciate your expertise on this.
 
va: read Mr Guffey's post carefully.

....the difference in length between the 8MM57 and the 8MM06 is .127", meaning I had .127" clearance between the shoulder of the case and shoulder of the chamber...
Click to expand...

If he can shoot a cartridge that is 0.127" shorter than the chamber without problems, then you should be able to shoot one that is 0.017" shorter.
 
Whether technically correct or not,the term "headspace" gets applied to the rifle chamber and to the brass.
Its really only correctly applied to the rifle chamber.
Click to expand...

Technically, yes. In particular when you are shooting factory ammo. However, when you reload and the shoulder of a bottleneck cartridge is moved further back than it is with factory ammo (as can happen with such arcane resizing instructions as "turn the die down until it contacts the shellholder, and then give it a 1/4 more turn"), you have just induced a situation in which your amount of headspace in your chamber with that particular ammo has increased. So, realize that headspace is a relationship of the rifle's chamber and the ammo being used.

Don
 
It would surprise me if your Ruger rifle was out of spec.

To boil it all down, are these cases safe or should I pull the bullets, save the powder and consider the cases a loss?
Click to expand...

Study a couple of loading manuals. Look for the topic "stretch ring" and "paper clip test"

Maybe 1/2 in forward of the case head,+ or -,is where the brass stretch tends to take place.The results are,the brass thins here,on the inside.Its not quite like an o-ring groove,but that would give you the idea.

You can sacrifice a case,and hacksaw it in half. Clean the burrs off,and observe the wall thickness near the case head.

I generally use the classic straightened paper clip.Bend about a 1/8 in 90 degree at the end.It will look like a short legged allen wrench.Use that for a probe to feel for an internal ring or groove in the case wall.
If there is no detectable case thinning,use the brass.
 
[QUOTE So, realize that headspace is a relationship of the rifle's chamber and the ammo being used.

][/QUOTE]This topic gets beaten to death .I've argued both sides of it. I agree with you that in the end,the point is controlling case stretch by controlling head clearance and "headspace" is a component in that plan.
I agree with some flexibility in the use of terminology just to communicate.

But the correct usage,headspace is the measurement from the breech face of the gun to the headspace feature in the chamber.(Rim,shoulder,belt,case mouth).
Its only in the rifle steel. Its only about whether the rifle itself is correct.

Technically,the ammo does not have headspace.

There IS a measurement called "head clearance" that is the relationship between the cartridge case and the chamber.As we reload,we certainly do effect head clearance.
We can push a shoulder back and create a condition that duplicates the problem of a rifle with excessive headspace. The term is "Excessive head clearance"
But the rifle headspace would be fine.
 
First the round likely can be fired and with no danger.

Its possible the case is loose enough that the shell just moves forward and little or no dent. Rather than pull them you can use them as practice rounds, fouling.

This gets nit picky on the term head space and what it all means.

The reality is that the purpose of a head space gauge is to get that relationship right.

The purpose of a round is to fit correctly in that head space and fire right.

So rather than focus on the subtle nuances, when someone is starting out, it take nothing away to treat your rounds as a variable head spaced gauges.

The important part is why we do this, how it all works and what it does.

I have done the paper clip thing and had cracks occur without that ridge. No idea if it is some and some or that hand me down wisdom. You can try it but its no for sure thing either.

Simply the first time you shoot a round you have fire formed that to your chamber.

You then accept that as the baseline and go from there.

I have tried Mr. Guffeys method, for me it sort of works.

I work mine down per my method and it suits me.

You get to decide what works for you. I don't try to pass his method on as it does not work for me and mine does what I need it to.

I will revisit it and do some more testing with it.
 
I appreciate all the feedback. Since the goal is accuracy, I would rather pull the bullets and powder and reload on in an accurate case. Using the feeler method to get 0.003 “bump” from a once fired case.
 
It might be useful to mention everything that has been said here applies to belted cases as well.They "headspace" on the belt which really is a useless appendage. Those cases should be resized with the same procedure as non-belted cases.
 
Mobuck wrote:
Old timer advice:
Step 1: For bolt action rifles, size brass until you are comfortable with the amount of effort required to close the bolt on the sized case.
Step 2: You're done.
Click to expand...

That's what I did for my semi-automatic rifles, too.
 
The Procedure:

(1) measure 6 once fired cases using the Hornady Comparator.
(2) Full length resize per manufacturer instructions and measure 3 cases.
(3) Full length resize using the 0.003 feeler gauge and measure 3 cases

Results:
(1) Six, once fired cases measured in at an average of 1.622. Lowest being 1.6215, highest at 1.6225

(2) Three cases full length resized averaged: 1.625 (2 were 1.625, third case was 1.6255)

(3) Theee cases full length with the 0.003 feeler gauge averaged: 1.628 (one case at: 1.6285, 1.6275, and 1.628)

(4) Unfired Federal Gold Medal March used as a control: 1.620x3

Bolt closes easy on group 2 and 4.
Bolt is tough to close on group 3.

Conclusion:
My Ruger has a “headspace” of 1.622.

If I want to “bump” back the shoulder, I should go to 1.620?

Please advise
 
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