fire it once & it should be repaired, hopefully the neck won't shorten
Brass undersized by .020” :(
- Thread starter Mram10us
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ALRIGHT you guys. I'll bite. What is the cow method. I've done the pistol powder and cream of wheat 100's of times but no cows.
OK iam slow. COW= cream of wheat. duh
25WSM
Well-Known Member
I freaking wish I was shooting some cow right now. I could use a nice thick steak. None here right now.
Shep
Shep
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Think it's an edge
25WSM
Well-Known Member
Anybody have a regular 338 rum reamer I could rent. Only need to move chamber .025
Shep
Shep
Alex Wheeler
Well-Known Member
If you shoot those cases with .020" headspace I bet you separate a case head the next time you shoot them. Thats too much to stretch them. Jamming wont be enough to hold them back, you have to make a false shoulder.
J E Custom
Well-Known Member
Even belted cases don't have that much head space (Normally .007 to .008) and they are notorious for case head separation if over sized after fire forming. The worst case can be up two .015 if all Maximum dimensions are combined. (Rare).
Head space is very important and should be held to a minimum. For belted cases I set the head space @ .0005 to .0015 for the first firing, then size only enough using the shoulder as a datum line instead of the belt for better case life and safety. This holds the head space to somewhere around .001 to .003 depending on the intended use.
For shouldered cases. I like .001 to .002 for accuracy and will go to .003 for auto loaders. Field gauges are rejection gauges and are any where from .006 to .008 and if they will chamber, it is best not to shoot them so you can see why .020 failed.
Some say no harm, no foul. I have set chambers back that had damage from case head separation from gas gouging caused by leaks just like when you blow primers it normally will scar the bolt face.
Excessive head space also loads the bolt excessively and can set the bolt lugs or the abutments back, creating excessive head space. it is always best to know exactly what the head space is in a chamber and then size one case down gradually until it will barely chamber and then make necessary adjustments to set the head space of your load correctly.
When fire forming wildcats it is best to have zero head space to hold the case secure for best forming by any means that will get you there.
J E CUSTOM
bigedp51
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How can excessive headspace cause more bolt thrust. The case must stretch to contact the bolt face when fired. This lowers the amount of bolt thrust because the case acts like a cars shock absorber. It also lowers the dwell time the base of the case is contacting the bolt face.
And a neck sized case with no head clearance delivers "MORE" bolt thrust than a full length resized case with head clearance.
Below a case with head clearance has to stretch to contact the bolt face. And the more headspace or head clearance you have the more the case absorbs and lessens the bolt thrust.
Below the brass case stretches and thins absorbing some of the bolt thrust. And there is no way that the case stretching to meet the bolt face increases the amount of bolt thrust.
Below is from the 1929 British textbook of small arms and the British used the base crusher system. And a hollow copper crusher was used to measure chamber pressure that allowed the firing pin to pass through the copper crusher. And the proof pressure cartridge had to be oiled to measure the actual chamber pressure. And a dry cartridge would produce a lower chamber pressure reading.
And two oiled proof pressure cartridges were used for proof testing. And if the headspace increased .003 or more the rifle failed proof testing.
And a neck sized case with no head clearance delivers "MORE" bolt thrust than a full length resized case with head clearance.
Below a case with head clearance has to stretch to contact the bolt face. And the more headspace or head clearance you have the more the case absorbs and lessens the bolt thrust.
Below the brass case stretches and thins absorbing some of the bolt thrust. And there is no way that the case stretching to meet the bolt face increases the amount of bolt thrust.
Below is from the 1929 British textbook of small arms and the British used the base crusher system. And a hollow copper crusher was used to measure chamber pressure that allowed the firing pin to pass through the copper crusher. And the proof pressure cartridge had to be oiled to measure the actual chamber pressure. And a dry cartridge would produce a lower chamber pressure reading.
And two oiled proof pressure cartridges were used for proof testing. And if the headspace increased .003 or more the rifle failed proof testing.
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J E Custom
Well-Known Member
It is very simple. A head space gauge is used to prevent excessive head space. this space is controlled by the gauge and if set correctly, there will only be that dimensional space between the case head and the bolt .000 to .0015 +. These dimensions are designed to keep the case from slamming into the bolt face and minimize the case stretch. The cartridges with the most body taper are the worst about moving before the case grips the chamber walls. most wild cats correct this by reducing the body taper allowing the case to grip the chamber, reducing bolt loading and case stretch.
There are not two dimensions for this clearance only one. it will be between the case head and the bolt face when chambered because the ejector is pushing it in the chamber. when it fires, it moves backwards by the amount of head space allowed. if the case grips the chamber before the case head is allowed to contact the bolt face there will be case stretch. you never use the breach face for this dimension, only the chamber and the bolt face.
The reason that head space gauges are called "Head Space gauges" is because they measure the space between the case head and the bolt face. I consider this dimension one of the most important dimensions and the reason head space gauges are made of hardened steel, so they cant be compressed and give a false reading. All sizing should be based on this dimension. More or less head space is up the the ammo maker or reloader and the results of improper head space is then on the re-loader.
J E CUSTOM
There are not two dimensions for this clearance only one. it will be between the case head and the bolt face when chambered because the ejector is pushing it in the chamber. when it fires, it moves backwards by the amount of head space allowed. if the case grips the chamber before the case head is allowed to contact the bolt face there will be case stretch. you never use the breach face for this dimension, only the chamber and the bolt face.
The reason that head space gauges are called "Head Space gauges" is because they measure the space between the case head and the bolt face. I consider this dimension one of the most important dimensions and the reason head space gauges are made of hardened steel, so they cant be compressed and give a false reading. All sizing should be based on this dimension. More or less head space is up the the ammo maker or reloader and the results of improper head space is then on the re-loader.
J E CUSTOM
bigedp51
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J E CUSTOM
You are full of fecal debris and have no idea what you are talking about.
I feel sorry for new reloaders who read your postings.
On top of this the Senior British Armourer in the UK told me about this when I collected Enfield rifles. On the Enfield rifle Minimum headspace was .064 and Maximum was .074.
Pacific Tool and Gauge offers three lengths of headspace gauges per rifle caliber. In order from the shortest to longest, they are: GO, NO-GO, and FIELD:
GO: Corresponds to the minimum chamber dimensions. If a rifle closes on a GO gauge, the chamber will accept ammunition that is made to SAAMI's maximum specifications. The GO gauge is essential for checking a newly-reamed chamber in order to ensure a tight, accurate and safe chamber that will accept SAAMI maximum ammo. Although the GO gauge is necessary for a gunsmith or armorer, it usually has fewer applications for the collector or surplus firearms purchaser.
NO-GO: Corresponds to the maximum headspace Forster recommends for gunsmiths chambering new, bolt action rifles. This is NOT a SAAMI-maximum measurement. If a rifle closes on a NO-GO gauge, it may still be within SAAMI specifications or it may have excessive headspace. To determine if there is excessive headspace, the chamber should then be checked with a FIELD gauge. The NO-GO gauge is a valuable tool for checking a newly-reamed chamber in order to ensure a tight and accurate chamber.
FIELD: Corresponds to the longest safe headspace. If a rifle closes on a FIELD gauge, its chamber is dangerously close to, or longer than, SAAMI's specified maximum chamber size. If chamber headspace is excessive, the gun should be taken out of service until it has been inspected and repaired by a competent gunsmith. FIELD gauges are slightly shorter than the SAAMI maximum in order to give a small safety margin.
Below a set of nine .308 Winchester headspace gauges in .001 increments. And the SAAMI cartridge and chamber drawing lists headspace as Min and Max with .010 between the two.
You are full of fecal debris and have no idea what you are talking about.
I feel sorry for new reloaders who read your postings.
On top of this the Senior British Armourer in the UK told me about this when I collected Enfield rifles. On the Enfield rifle Minimum headspace was .064 and Maximum was .074.
Pacific Tool and Gauge offers three lengths of headspace gauges per rifle caliber. In order from the shortest to longest, they are: GO, NO-GO, and FIELD:
GO: Corresponds to the minimum chamber dimensions. If a rifle closes on a GO gauge, the chamber will accept ammunition that is made to SAAMI's maximum specifications. The GO gauge is essential for checking a newly-reamed chamber in order to ensure a tight, accurate and safe chamber that will accept SAAMI maximum ammo. Although the GO gauge is necessary for a gunsmith or armorer, it usually has fewer applications for the collector or surplus firearms purchaser.
NO-GO: Corresponds to the maximum headspace Forster recommends for gunsmiths chambering new, bolt action rifles. This is NOT a SAAMI-maximum measurement. If a rifle closes on a NO-GO gauge, it may still be within SAAMI specifications or it may have excessive headspace. To determine if there is excessive headspace, the chamber should then be checked with a FIELD gauge. The NO-GO gauge is a valuable tool for checking a newly-reamed chamber in order to ensure a tight and accurate chamber.
FIELD: Corresponds to the longest safe headspace. If a rifle closes on a FIELD gauge, its chamber is dangerously close to, or longer than, SAAMI's specified maximum chamber size. If chamber headspace is excessive, the gun should be taken out of service until it has been inspected and repaired by a competent gunsmith. FIELD gauges are slightly shorter than the SAAMI maximum in order to give a small safety margin.
Below a set of nine .308 Winchester headspace gauges in .001 increments. And the SAAMI cartridge and chamber drawing lists headspace as Min and Max with .010 between the two.
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mwkelso
Well-Known Member
This is good to know. I have noticed that faint line at the bottom of my 300wm brass. I've followed the die instructions to a T, and just assumed that was a byproduct or reloading.
If I'm understanding correctly, the way to mitigate a case separation is to make sure the shoulder is not bumped too far to ensure there is proper head clearance?
