I seriously doubt this is case head separation but what do you guys think?

[J E Custom]

Sorry, I don't think you Mean .064 to .074 is the head space. That is the rim thickness for the rimed case. and acts as a go gauge. Rimed case head space is set off the rim, and the different gauge rim thicknesses are the way head space is set or found, the .064 is zero head space (Minimum)and the .067 gauge gives you .003 thousandths of head space, which is considered the maximum for normal head space.

The .074 gauge is a no go/field gauge and gives you .010 thousandths Head space and makes the rifle unsafe. Shouldered or belted cases cant operate at these extreme head spaces and normally rejected at .006 to .008 depending on the type and use of the weapon.

Sorry, Didn't want anyone to think that any firearm could operate with those kinds/amounts of head space.

J E CUSTOM

 

[J E Custom]

Wouldn't excessive head space cause the primers to be pushed out?
Just wondering?
I thought that was a symptom of oversizing your cases

First, Primers are not used to set head space and should always be seated flush or below the case head. when the cartridge is fired, the first thing to move is the case and it moves back to the bolt face the amount of the head space (.000 to .003)thousandths The primer doesn't move it is compressed causing it to flatten (One of the signs of pressure) The inside of the primer will move back however much it can based on pressure but the face of the primer never exceeds beyond the cartridge face. (the bolt face will not let it).

Over sizing the cases only cause case stretch and the primer will never be sticking out of the case head after firing.

Over sizing is variable based on the reloaders requirements and beliefs.
If ease of loading is the priority, more sizing may be the norm. If case life and wear and tear on equipment is the priority less sizing is the norm.

J E CUSTOM

 

[Edd]

Don't confuse Headspace with Head Clearance.

Headspace is a measurement independent of a cartridge. Head clearance is the headspace minus the cartridge length.

 

[timberelk]

Im back with some info...

First picture is a case that stretch approx .012" (from 2.025 to 2.037 after being fired once). Cut it in half with a dremel and I can't seem to see any eveidence of case beginning to separate.

Next picture is the black lines of another case that stretched to 2.037 from 2.025 after being fired once (both pieces of brass have been fired a total of 2 times). Those black line signify the locations that I measured the diameter of the case.

Before I full length resized:
Case length = 2.037
Shoulder via hornday guage = .626"
Diameter at top ring = .458"
At middle ring = .461
At bottom ring = .469

After full length resizing(die touch shell holder plus 1/4 turn)
Case length = 2.043 (grew .006")
Shoulder = .624 (shrank by .002")
Top line = .453 (shrank .005")
Middle line = .458 (shrank .003")
Bottom line = .466" (shrank .003")

 

[timberelk]

Here is a picture of the same cut piece of brass but I cleaned it up with some sand paper so you could see the wall thickness better

 

[J E Custom]

Looks good !!! it appears that you don't have case stretch and all you have to do is minimum sizing for brass life and fit.

The mark at the bottom of the case indicates that the chamber is a little larger than the case after sizing (But not enough to be a problem) and as long as you don't move the shoulder very much your brass should be ok.

J E CUSTOM

 

[Barrelnut]

Before the pros show up.... IMO all is really OK here. Your brass (actually your neck) is growing by .006 due to the brass flowing and being pushed upward by the die. (The brass has to go somewhere.) Having a cartridge with a 20% shoulder angle is more prone to this than cartridges with sharper shoulder angles like a 6.5 Creedmoor or WSM cartridge. You are really just gonna have to learn to live with it.

I would make sure my expander ball was polished some and the inside of the necks were lubed good before you run them thru the die. The expander drags on the neck and can STRETCH it. Also, if it is good brass with consistent neck thickness, you can use bushing dies that minimally compress the neck and throw away the expander ball altogether.

It's really the nature of the beast.

 

[timberelk]

Before the pros show up.... IMO all is really OK here. Your brass (actually your neck) is growing by .006 due to the brass flowing and being pushed upward by the die. (The brass has to go somewhere.) Having a cartridge with a 20% shoulder angle is more prone to this than cartridges with sharper shoulder angles like a 6.5 Creedmoor or WSM cartridge. You are really just gonna have to learn to live with it.

I would make sure my expander ball was polished some and the inside of the necks were lubed good before you run them thru the die. The expander drags on the neck and can STRETCH it. Also, if it is good brass with consistent neck thickness, you can use bushing dies that minimally compress the neck and throw away the expander ball altogether.

It's really the nature of the beast.

So I'm just going to have to live with the class stretching approx .010" each firing? How many firing should I expect to get? And how much should I trim the case after it fired? Back to min or just to .035 or .034 (max is .035") ?

 

[bigedp51]

Sorry, I don't think you Mean .064 to .074 is the head space. That is the rim thickness for the rimed case. and acts as a go gauge. Rimed case head space is set off the rim, and the different gauge rim thicknesses are the way head space is set or found, the .064 is zero head space (Minimum)and the .067 gauge gives you .003 thousandths of head space, which is considered the maximum for normal head space.

The .074 gauge is a no go/field gauge and gives you .010 thousandths Head space and makes the rifle unsafe. Shouldered or belted cases cant operate at these extreme head spaces and normally rejected at .006 to .008 depending on the type and use of the weapon.

Sorry, Didn't want anyone to think that any firearm could operate with those kinds/amounts of head space.

J E CUSTOM

You are incorrect, British military headspace is .064 minimum and .074 max with "NO" in-between headspace settings.

The American SAAMI headspace is .064 GO and .067 NO-GO and this is for setting headspace on a new rifle. Meaning you have three thousandths to play with when setting up the new or rebarreled rifle. And the SAAMI rim thickness can be from .054 to .064

Below is a SAAMI cartridge and chamber drawing for the .308 Winchester and minimum headspace is 1.630 and maximum headspace is 1.640 with ten thousandths between min and max headspace. And the GO gauge is 1.630 and the NO-GO gauge is 1.634 and is used for setting up a new rifle.

Below are a set of .308 Winchester gauges in .001 increments, and used to check the amount of headspace increase out to maximum headspace or the Field gauge. Meaning you don't replace the bolt or re-barrel the rifle when the headspace is longer than the NO-GO gauge at 1.634 because you still have .006 left before you reach maximum headspace of 1.640.

Bottom line, I hope you do not think a rifle is worn out when headspace increases past the NO-GO gauge when the SAAMI gives you .010 headspace to play with.

The British used two oiled proof cartridges to proof check the Enfield rifle and if the headspace increased .003 or more the rifle failed proof testing due to lug setback. But in normal service if the Enfield rifle bolt closed on the .074 headspace gauge with the longest #3 bolt head the bolt was replaced. If the bolt was replaced and the rifle failed the .074 gauge the rifle was sent back for overhaul.

 

[bigedp51]

So I'm just going to have to live with the class stretching approx .010" each firing? How many firing should I expect to get? And how much should I trim the case after it fired? Back to min or just to .035 or .034 (max is .035") ?

timberelk

What make full length resizing die are you using? Your cases are not stretching when fired, they are "GROWING" when you resize the cases.

When I use a small base die the OAL of the case becomes longer than if I used a standard die. Meaning when the case is squeezed in a smaller diameter die the case will grow more in length.

You need to measure a fired cases diameter and OAL and measure again after sizing and see how much the case increases in length. So one more time, your problem could be your sizing die might be at minimum dimensions and is squeezing the case smaller than needed and making the case grow .010 after it is sized.

 

[timberelk]

timberelk

What make full length resizing die are you using? Your cases are not stretching when fired, they are "GROWING" when you resize the cases.

When I use a small base die the OAL of the case becomes longer than if I used a standard die. Meaning when the case is squeezed in a smaller diameter die the case will grow more in length.

You need to measure a fired cases diameter and OAL and measure again after sizing and see how much the case increases in length. So one more time, your problem could be your sizing die might be at minimum dimensions and is squeezing the case smaller than needed and making the case grow .010 after it is sized.

Please refer to post #60, I believe I did those exact measurements before sizin and after sizing

 

[bigedp51]

First, Primers are not used to set head space and should always be seated flush or below the case head. when the cartridge is fired, the first thing to move is the case and it moves back to the bolt face the amount of the head space (.000 to .003)thousandths
J E CUSTOM

The first thing to move when the cartridge is fired is the primer to the rear until it contacts the bolt face. Then as the chamber pressure increases to the yield strength of the brass the case stretches to meet the bolt face.And on lower pressure cartridges the primer will always protrude by the amount of head clearance you have.

I'm seriously beginning to doubt your knowledge on firearms by your statements you have posted in this forum.

 

[Barrelnut]

So I'm just going to have to live with the class stretching approx .010" each firing? How many firing should I expect to get? And how much should I trim the case after it fired? Back to min or just to .035 or .034 (max is .035") ?

Maybe 7~10 loadings. Your primer pockets may get too loose and cause you to toss the piece of brass before the growth during resize does.

 

[bigedp51]

Look at the image below, when the case is resized and squeezed it makes the case grow in over all length.
And if the case shoulder is pushed back to far when sized the case can stretch and thin.
Meaning it will case a case head separation.

This is why people with deep pocket will send fired cases to a custom die manufacture and have a custom die made. Then this person has a die that doesn't over squeeze the case and not have to trim the case every time the case is fired.

My guess to your problem is your die is over resizing the case in diameter and why it is getting so long after sizing.

Now again what brand die are you using? It might be time to try another die.