300 Win Mag Headspace

[bigedp51]

Below a factory loaded Winchester .303 British case fired once in a Enfield rifle. The Bolt would not close on a SAAMI NO-GO gauge, so the headspace was between .064 and .067. And maximum British military Enfield rifle headspace is .074.

The case stretched .009 on its first firing because it had a rim at minimum SAMMI thickness. Meaning excessive head clearance or air space between the base of the case and the bolt face.

Below with my RCBS case mastering gauge I can measure case wall thickness and and thinning. I think of it as my $100.00 bent paper clip but as you can see it measures in one thousandths of an inch.

My 1950 No.4 Enfield below has had the headspace adjusted from just kissing the rear of the case to .010 over maximum military headspace or .058 to .084. I did this to test the effects of headspace and head clearance and its effects on case stretching when fired.

Bottom line there is a reason why you are told to keep your shoulder bump to .001 to .002 and not stress the brass beyond its elastic limits. And a belted magnum case can stretch just like any other type case the first time it is fired. And the key word is head clearance and the distance the case is allowed to stretch when fired.

 

[J E Custom]

You still didn't explain why a belted case is so special that head clearance and fire forming is not required.

It doesn't matter what stops the forward movement of the case in the chamber as a headspacing method. It is the head clearance or air space between the rear of the case and the bolt face that allows the case to stretch and thin when fired.

And this is the very reason on a belted case you let the case headspace on its shoulder and not the belt. And with variations in case manufacture you could have as much as .012 head clearance.

Bottom line, just because a case has a belt doesn't mean it will not stretch, thin and cause case head separations.

Head space is the clearance between the case head and the front of the belt on belted cases. It is the clearance between case head and the datum line on shouldered cases. With rimed cases it is the back of the case head to the front of the case head. With rimless cases it is the clearance between the back of the case head and the end of the case body. There has to be some clearance in order to be able to chamber the cartridge and as long as it is not excessive (.000 to .004) case life will be good, the less head space the better as long as you can chamber the cartridge.

To answer your question, I would never say that belted cases don't require head space, In fact SAMMI recommends .004 Maximum to prevent case head separation. I prefer to set the head space on belted cases close because if the belt is two or three thousandths short or right at the minimum dimension that dimension can be added to the head space set by the go gauge and could end up .007 or .008 thousandths. The limit of the field gauge and case head separation is more likely.

The reason that belted cases can be fired in a custom chamber is because the head space is held to a safe dimension if done correctly.
Belted cases are by design much smaller in the chamber for ease in chambering in a dirty chamber or in a life threatening situation that a fouled chamber could be serous. any belted case grows in length when fired the first time because case life was not the concern when it was first designed, hunter safety was.

Belted cases head space on the belt and not on the datum line or front of the case head so wildcats form easy with reduced loads, then after the first firing, chamber fit is up to the re-loader and the desired case life. also On the other terminology of head clearance and head space. they are one and the same because head space is determined by the head space gauge pushing against the belt or datum line and the head space is set behind the gauge as described early in this post and when fired head clearance will disappear because the cases will fill the clearance (Stretch) from the pressure and in a normal load the head space will be reduced but not enough to prevent chambering. But high pressure loads will become a minus head space dimension because the chamber expansion and brass spring back. So some sizing will/must be done in order to be able to chamber the case.

Case head separation normally only occurs with excessive head space or over worked/sized brass and age.

Once I figured out how important proper head space was I have not had a single case head separation in over 40 years.

J E CUSTOM

 

[bigedp51]

Rimmed and belted cases date from a time when manufacturing methods were not at the same standards and quality of today's cartridges. And the first British belted case was around 1910 and it was needed because of the smaller shoulder of these cases for reliably feeding and headspacing.

Below a rimmed 450 martini-henry cartridge, on the left a modern made cartridge and on the right a cartridge from 1879 and the British Zulu wars.

And you still not have explained why "YOU" think that head clearance does not matter on a belted case. You keep side stepping the question and filling your postings with bovine skat that has nothing to do with the subject. Or "WHY" you think a belted case does not need a false shoulder or be jammed if it has excessive head clearance.

Headspace is one thing and head clearance is a separate issue that has to due with cartridge case manufacturing tolerances.

You just don't get it, I have had brand new cases over .009 shorter than my GO gauge. And these short cases were jammed into the rifling to keep them from stretching the first firing. And if the case stretches on its first firing it will be very short lived. And a belted case with chamber and case variations can have as much as .012 head clearance.

And again if the belt was so important why do reloaders let the belted case headspace on its shoulder to get longer case life.

And this is why your posting below is pure BS and misleading to anyone reading it and just plain bad bad advice.

With a belted case there is no need to use a false shoulder or jam the bullet in the lands. The belt solves all these problems. all that is necessary is to load and shoot your ammo and it will fire form without making adjustments in the powder charge to prevent over pressure.

The only time that a reduced load is recommended on a belted case, is when forming a wildcat that calls for a large increase in powder/case capacity.

J E CUSTOM

 

[J E Custom]

Rimmed and belted cases date from a time when manufacturing methods were not at the same standards and quality of today's cartridges. And the first British belted case was around 1910 and it was needed because of the smaller shoulder of these cases for reliably feeding and headspacing.

Below a rimmed 450 martini-henry cartridge, on the left a modern made cartridge and on the right a cartridge from 1879 and the British Zulu wars.

And you still not have explained why "YOU" think that head clearance does not matter on a belted case. You keep side stepping the question and filling your postings with bovine skat that has nothing to do with the subject. Or "WHY" you think a belted case does not need a false shoulder or be jammed if it has excessive head clearance.

Headspace is one thing and head clearance is a separate issue that has to due with cartridge case manufacturing tolerances.

You just don't get it, I have had brand new cases over .009 shorter than my GO gauge. And these short cases were jammed into the rifling to keep them from stretching the first firing. And if the case stretches on its first firing it will be very short lived. And a belted case with chamber and case variations can have as much as .012 head clearance.

And again if the belt was so important why do reloaders let the belted case headspace on its shoulder to get longer case life.

And this is why your posting below is pure BS and misleading to anyone reading it and just plain bad bad advice.

I am realy glad you like my post. !!!

The problem is you have all these nice drawings and don't know how to read them. You appear to know something about the 303 Enfield
but you tell everyone that it requires .054 to .084 of head space.

If you realy believe that any cartridge has that much head space Then no one can help you. What you are recommending will get someone killed. Everyone can learn something if they listen including me. I am not sure why you like to misinterpret my post and make comments that not only make no sense, but are dangerous.

The nice drawings you posted on how head space was measured were all wrong except for the shouldered case drawing. A belted case does "NOT" head space from the back of the case head to the datum line. you set head space off the width of the belt, only after you fire a belted case the first time can you use the datum line or shoulder to fit the chamber and eliminate the belt. You must have altered most of your drawings to make them agree with you and this is not only wrong but dangerous for those that don't know better.

The 303 is a very lo pressure cartridge and SAMMI recommends 45,000 max and test pressure of 66,137 most new cartridges will exceed even the test pressure and the only reason the cartridge has the head space it does is because it was built for the military and has to function under any circumstances brass and life was not a consideration. I would tell you what the actual recommended head space is but that would be to easy.

I don't understand what you have against me but that doesn't bother me because I do know how to build rifles and and all you can contribute is bull **** that will get someone hurt and all that I can do is to try to keep that from happening by posting the truth and try not to get personal. Sorry someone peed in your Cheerios, but it wasn't me.

So no matter how venomous your post are to me, I will try to keep people out of trouble if i can, and keep my post civil. Sorry guys but it has to be said. "This guy is dangerous"

J E CUSTOM

 

[bigedp51]

J E CUSTOM
You still didn't answer the question about belted cases and head clearance, And all you did was write over five paragraphs above crying and covering up for yourself and not answering the question.

And then you wonder what I have against your posting here. And that answer has to do with variations in chambers and the cases themselves.

You don't even acknowledge why reloaders jam their bullets or make a false shoulder in the first place. Or that chambers and cases have plus and minus manufacturing tolerances. Or a short case fired in a long chamber is going to stretch.

And then you say don't worry the belt will solve all his problems. So why did the OP want headspace tighter than minimum SAAMI standards and minimum head clearance in the first place. Because he doesn't want case stretch and case head separations.

With a belted case there is no need to use a false shoulder or jam the bullet in the lands. The belt solves all these problems. all that is necessary is to load and shoot your ammo and it will fire form without making adjustments in the powder charge to prevent over pressure.

The only time that a reduced load is recommended on a belted case, is when forming a wildcat that calls for a large increase in powder/case capacity.

J E CUSTOM

 

[J E Custom]

J E CUSTOM
You still didn't answer the question about belted cases and head clearance, And all you did was write over five paragraphs above crying and covering up for yourself and not answering the question.

And then you wonder what I have against your posting here. And that answer has to do with variations in chambers and the cases themselves.

You don't even acknowledge why reloaders jam their bullets or make a false shoulder in the first place. Or that chambers and cases have plus and minus manufacturing tolerances. Or a short case fired in a long chamber is going to stretch.

And then you say don't worry the belt will solve all his problems. So why did the OP want headspace tighter than minimum SAAMI standards and minimum head clearance in the first place. Because he doesn't want case stretch and case head separations.

I have tried very patiently to explain to you that all belted cases will have excessive clearance/space in the chamber until first fired. everyone should know that all cases/cartridges have differences in there dimensions when new and we solve these problems by re
loading. If you set the head space on a belted case to .0000 there will still be some case stretch the first time fired because of the small size of the case body. This is by design.

Also I did not say don't jam the bullet, I only said you don't "Have to".

You obviously don't read the entire post before you post your reply because i have re read my post and they are very clear or you have trouble comprehending.

What ever the problem, I cant help you. Maybe the original poster will wade through your BS and come up with a reasonable and safe solution.

You can keep on with your personal attacks on me but it wont make you look smarter, and only show what you don't know. due to your personal attacks on me, I feel obligated to continue to correct you on dangerous matters that should get someone hurt. I realy don't care about the rest or what you do with your own rifles and loading.

J E CUSTOM

 

[Edd]

The root cause of the conflict in this discussion is the same as it was the last time the subject was discussed. There is either a lack of understanding or an unwillingness to acknowledge the difference between Headspace and Head Clearance.
https://saami.org/saami-glossary/?letter=H

HEADSPACE
The distance from the face of the closed breech of a firearm to the surface in the chamber on which the cartridge case seats.

This measurement has a huge variation based on the cartridge.
An Example...
The minimum headspace spec for a 308 Winchester is 1.630".
The minimum headspace spec for a 300 Ultra Mag is 2.4742"


HEAD CLEARANCE
The distance between the head of a fully seated cartridge or shell and the face of the breech bolt when the action is in the closed position. Commonly confused with headspace.

A chosen number for this measurement will work for many, perhaps all, cartridges.

 

[bigedp51]

The root cause of the conflict in this discussion is J E CUSTOM because he thinks he is the only one who knows how to reload.

The OP asked this same question in another well known reloading forum below. There were 10 posts and no conflicts.
http://forum.accurateshooter.com/threads/300-win-mag-headspace.3961730/

The OP Asked the same question here and can1010 gave the OP the specific case measurements and advice. And J E CUSTOM even gave him a "like" for the post below.

cutting the chamber to the belt will not matter because the datum measurement to the shoulder is .014 short on ADG Brass and is no way to adjust that by cutting to the belt measurement there will still be .014 case stretch. that is about normal with all belted cases that measured. I fireform mine with light load and jammed bullet to help with the problem

The OP then asked what was better jam or the false shoulder and I gave my opinion in post number 10. And then came post number 11 with someone changing his mind about jam and saying the belt would solve all the problems.

Now who is the root cause of the conflict here by changing his mind.

 

[J E Custom]

The root cause of the conflict in this discussion is J E CUSTOM because he thinks he is the only one who knows how to reload.

The OP asked this same question in another well known reloading forum below. There were 10 posts and no conflicts.
http://forum.accurateshooter.com/threads/300-win-mag-headspace.3961730/

The OP Asked the same question here and can1010 gave the OP the specific case measurements and advice. And J E CUSTOM even gave him a "like" for the post below.


The OP then asked what was better jam or the false shoulder and I gave my opinion in post number 10. And then came post number 11 with someone changing his mind about jam and saying the belt would solve all the problems.

Now who is the root cause of the conflict here by changing his mind.

The reason I gave some a like is because they gave good information
and then you started with your drawings and opinions once I posted and you saw my post, and screwed up the post with your assault on me. We can settle this if you want to stop hiding behind your keyboard an meet face to face.

And one other comment, If I ever heard a gunsmith mention using an o ring or a rubber band to set head space or reduce the amount of head space rather than fixing it, I would run like hell and stay as far away from any firearm he built as I could !!!

I cant understand where you come up with this **** but you do and it scares me that you actually believe it.

This back and forth bantering is over and you can keep it up if you want to, Maybe you can find another smith that will agree with you. I know many good smiths that will not get into these debates with you and warned me to do the same because of you venomous post with anyone that disagrees with you. Most people on this site are interested in learning something including me and these type of post are counter productive. So you can have the last word because the membership deserves better and I'm done with trying to help you.

J E CUSTOM

 

[bigedp51]

Here is what you do not understand, many people collect old milsurp rifles. And many of these rifles have headspace beyond a Field gauge. But you can still shoot and reload for these old rifles with reduced loads and fire formed cases.

And these old rifles have worn throats and you can not jam, and a false shoulder can cause cracked necks. And since a .303 British has a rim you can slip a rubber o-ring around the case and safely fire form the case. And this is used instead of lubing the case to fire form the case and doubling the bolt thrust.

I didn't come up with the o-ring or rubber band method, I was told about it in Enfield milsurp forums. And these methods were used long before I started reloading.

If you look at a SAAMI cartridge and chamber drawing it lists headspace as min and max with .010 in between the two. And a GO and NO-GO gauges are used for installing new barrels with approximately .003 wiggle room between Go and NO-GO. And you are allowed to have about .007 wear to the Field gauge.

Below are my Enfield headspace gauges and at the max military headspace of .074 and a rim thickness of .058 you have .017 head clearance. The rifle is safe by military standards but American made brass has thin rims. And a rubber o-ring will take up the .017 head clearance. Meaning there is no difference between the rubber o-ring, jam or a false shoulder, all three do the same thing.

Below is my 1950 No.4 Enfield rifle that has been fitted with two bolt heads to compensate for variations in rim thickness.

I'm 68, have been reloading for over 47 years. I have never had a case head separation or a kaboom. And you are not as smart as you think you are, and most importantly I have never ask you for any advice or help.

And all 50 cases below were fire formed using a o-ring method and a reduced load. The cases are still going strong and only fail from cracked necks.

And the rubber o-ring keeps from what happens in the animated image below. And the problem is called head clearance or the air space behind the case and the bolt face.

Bottom line, you can compensate for longer headspace settings even to Field gauge limits by fire forming your cases. And using any method that holds the case against the bolt face and prevents the case from stretching. And nothing I have done is dangerous and a rubber o-ring will not cause a pressure spike like jamming your bullets can.

And the only thing dangerous here is your lack of knowledge and ignorance.

 

[bigedp51]

Below more dangerous reloaders using o-rings
And I'm not in this posting under any screen name or did I invent the idea of using o-rings.
Please note that no one is screaming his head off saying how dangerous this is.

.303 British large chambers
http://castboolits.gunloads.com/showthread.php?350578-393-British-large-chambers

 

[J E Custom]

Here is what you do not understand, many people collect old milsurp rifles. And many of these rifles have headspace beyond a Field gauge. But you can still shoot and reload for these old rifles with reduced loads and fire formed cases.

And these old rifles have worn throats and you can not jam, and a false shoulder can cause cracked necks. And since a .303 British has a rim you can slip a rubber o-ring around the case and safely fire form the case. And this is used instead of lubing the case to fire form the case and doubling the bolt thrust.

I didn't come up with the o-ring or rubber band method, I was told about it in Enfield milsurp forums. And these methods were used long before I started reloading.

If you look at a SAAMI cartridge and chamber drawing it lists headspace as min and max with .010 in between the two. And a GO and NO-GO gauges are used for installing new barrels with approximately .003 wiggle room between Go and NO-GO. And you are allowed to have about .007 wear to the Field gauge.

Below are my Enfield headspace gauges and at the max military headspace of .074 and a rim thickness of .058 you have .017 head clearance. The rifle is safe by military standards but American made brass has thin rims. And a rubber o-ring will take up the .017 head clearance. Meaning there is no difference between the rubber o-ring, jam or a false shoulder, all three do the same thing.

Below is my 1950 No.4 Enfield rifle that has been fitted with two bolt heads to compensate for variations in rim thickness.

I'm 68, have been reloading for over 47 years. I have never had a case head separation or a kaboom. And you are not as smart as you think you are, and most importantly I have never ask you for any advice or help.

And all 50 cases below were fire formed using a o-ring method and a reduced load. The cases are still going strong and only fail from cracked necks.

And the rubber o-ring keeps from what happens in the animated image below. And the problem is called head clearance or the air space behind the case and the bolt face.

Bottom line, you can compensate for longer headspace settings even to Field gauge limits by fire forming your cases. And using any method that holds the case against the bolt face and prevents the case from stretching. And nothing I have done is dangerous and a rubber o-ring will not cause a pressure spike like jamming your bullets can.

And the only thing dangerous here is your lack of knowledge and ignorance.

Now that was a good post and most of the information was good with a few exceptions. I have worked on old military rifles and believe that if they are bad, fix them.

The reason I would recommend fixing them is because they have a history of blowing up in your face for many reasons. There are some rifles made during the second world that are notorious for failure from poor metallurgy to poor or no testing.

If you feel comfortable shooting these old rifles in poor condition and out of spec. that is your choice. I don't want anyone to get hurt so I just choose to fix problems and not risk other problems. I love the old rifles and regularly fix them, but I also know there limits and stay away from there limits.

Some of your comments were not called for but that's Ok. Because I am 77 and have been reloading for for every type of firearm for over 55 years I have also been building all types of rifles for many years, so I know there strong points and weak points.

J E CUSTOM

 

[bigedp51]

J E CUSTOM

I do not need your approval to say anything here and again I have never asked you for any help nor do I need it.

You are standing here now with your foot in your mouth from your lack of knowledge. And in the links I posted you didn't see anyone saying anything bad about the o-ring method of fire forming cases.

And you can go to any Enfield forum or cast bullet forum and read about o-rings and fire forming. And I do not need to "FIX" any of my rifles because the SAAMI allows .010 between the GO gauge and Field. And all you need to do is fire form the case and use any method to hold the case against the bolt face. Meaning you do not need to fix any rifle until it fails the Field gauge test

If you realy believe that any cartridge has that much head space Then no one can help you. What you are recommending will get someone killed. Everyone can learn something if they listen including me. I am not sure why you like to misinterpret my post and make comments that not only make no sense, but are dangerous.

Sorry guys but it has to be said. "This guy is dangerous"

J E CUSTOM

Your statement above in red tells it all, you actually think you are the only one who know how to reload. And in my opinion your ego is much bigger than your ability. The problem today is we have too many midgets sitting at their computers and pretending to be giants.

And you have the audacity to call me dangerous, because of your lack of knowledge and experience.

The O-ring solves a head clearance problem just like a false shoulder and jam does. And I have been fire forming my .303 British cases like below this way for over 20 years.

 

[J E Custom]