Head space gage for 308

tjndaltx · July 15, 2009, 03:55 PM

I'm trying to use a Dillon headspace gage to set my die to the correct depth.

No matter what I do I cannot get the set the shoulder at the correct point for the case head to lie below the high point on the gage. I have the die in so far the rings will not even connect with the threads on the die.

Obviously, I'm doing something wrong here.

Should I trim my cases to length before using the sizing die with the headspace gage?

Any ideas on what might be wrong?

Help!!!

**Unclenick** · July 15, 2009, 04:26 PM

Welcome to the forum.

What press and what die are you using? Watch this Lee help video for setting one of their rifle sizing dies up. It is the way all standard sizing dies are set up.

Did you read the cartridge name on the side of the die and does that name match the cartridge you are trying to load? I know that sounds foolish, but you'd be surprised how common it is for people to be mislead into thinking there is no difference between rounds whose name starts with the same number, like .300 or 7.62, when in fact there are dozens of rounds with drastically different case shapes whose names start with the same characters as some others, so it is worth checking.

Did you follow instructions for getting the decapper and expander ball stem correctly adjusted? If not, they can prevent the case from entering the die completely.

One last thing: are the cases from rounds you fired in the same gun you are loading for? If so, and that gun has a long chamber, it could be difficult to set the shoulder back 100%, but it will still fit in that same long chamber just fine. You generally only need to meet the gauge numbers if you are going to fire the ammo in different guns. There are a few exceptions: auto-loading rifles sometimes need original case sizing. If the cases are long, such as once-fired surplus, it can occasionally be necessary to buy a special extra-small sizing die called a small base die, which knocks the shoulders back an extra couple of thousandths. If you have a press that uses standard shell holders, you can also get a couple of thousandth ground off the top of the holder so the die can be set up closer to the case head.

You can also usually get an extra two or three thousandths off the shoulder by raising the case up into the die, counting to five, withdrawing it and letting it rest outside the die for another count of five, then running it back up into the die again for a second count of five. This is a temporary remedy while you wait for your small base die to arrive or while you are working on taking a little metal off the top of the shell holder. It is not a good permanent solution because it makes you size and expand the neck twice for each loading, and that will harden it prematurely, and unless you learn to anneal your case necks, that will shorten case life.

tjndaltx · July 15, 2009, 05:15 PM

Hi Unc Nick again,

I'm using a Redding T-7 turret press with Lee dies.

Not stupid. But my die is a 308 Winchester.

"Did you follow instructions for getting the decapper and expander ball stem correctly adjusted? If not, they can prevent the case from entering the die completely."

I removed the decapper from the die since there are no primers in the cases. Guess I could have left it in but I didn't. Did I goof there?

These rounds will be fired in different guns. One a bolt the other a semi-auto.

Maybe I should buy the small base die?

**Unclenick** · July 15, 2009, 05:37 PM

Removing the decapper also removed the expander. The problem for the die maker is that SAAMI specs case walls for a tolerance of 0.004" thickness (max OD over the bullet, -0.008", which includes two wall thicknesses). The problem then is how to size the neck so the ID of the case mouth fits the bullet? A thick neck will size the hole too small, while a thin one might leave a loose fit. So what they do is cut the die to size the thinnest neck in the tolerance range, which leaves the inside of the neck about 0.008" too small if a case has the maximum wall neck. To get the neck ID the right size to accept and hold the bullet regardless of how small it came out of the die, they force it to pass over that expander. So, chances are, without the expander you have necks that are too narrow for best bullet tension and some will crush the shoulder when you try to load them.

Since you have your decapper out of the die anyway right now, before putting it back and getting a small base die, try sizing a case with a 0.002" automotive feeler gauge slipped in under the case head. That will raise it enough so the standard die makes it the same shoulder-to-head length that a small base die will. See if that's enough for what you are trying to do?

tjndaltx · July 15, 2009, 05:43 PM

I don't know that I have a feeler gauge, so may have to pick one up tomorrow. But I'll sure try it.

Thanks for the explanation.

I bought the 308 die set used and I regret that. I'm going to buy a new set along with the small base die.

Slamfire · July 15, 2009, 06:05 PM

What you describe is most unusual. I have a set of Dillion 30-30 dies and they set up properly on my Redding T-7.

If you have screwed the die so far down in the turret head that the threads of the die are below the turret head, something is obviously wrong.

Does the bottom of your die touch the shell holder when the ram is raised?

If the die is in fact touching the shell holder, than it is futile to screw the die any more through the turret head.

It is futile because the die body is too long. Once you touch the shell holder, and the shoulder is not being moved back, well you can't shorten that distance any more by raising or lowering the die.

One way to shorten the distance from the bottom of the die, and the shoulder inside the die, is to remove material from the bottom of the die. This shortens the die.

Wish I could see a picture of what you are doing, because I am guessing this is your problem.

jepp2 · July 15, 2009, 06:20 PM

I have a Lyman die (.223 Remington), that I tried everything Unclenick recommended, and I never could get the shoulder set back enough to properly size the brass. I have headspace gauges (the true male headspace gauge) and I could confirm that indeed the shoulder wasn't being set back enough. I switched to a Redding die set, rather than remove height from my shell holder. So there are some dies that just will not set the shoulder back adequately.

alloy · July 15, 2009, 06:25 PM

As a newbie who probably shouldn't give any advice....the L.E. Wilson cartridge gage simplified setting up my sizing to spec, and I will now go back to reading instead of talking.

Lyman also makes one.

tjndaltx · July 15, 2009, 06:45 PM

Unc Nic,

The small base die, is that the sizer die that sets the shoulder back a little further than the normal die?

Slamfire · July 16, 2009, 10:48 AM

Maybe I should not be answering this, but old small base dies would set the shoulder back so much, you could/would get case head separations.

Very few people use cartridge headspace gages to set up their dies, so you will hear, time and time again, "small base over work brass". And this is due to these folks just setting a small base die to the shell holder "plus a quarter turn".

However even reloading companies learn to protect us from our ignorance. I purchased a new RCBS small base X die in 308. With the die touching the shell holder, it will not size brass any shorter than gage minimum. Something has changed.

This is in fact a problem as cases do not rebound the same. Depending on the rifle it was fired in, (like my FAL) and depending on the work hardening of the cases, there have been times I have had to set the small base down below “gage minimum”. Well gage minimum for the average 308 I own. Now I can’t unless I remove material from the bottom of the die.

**Unclenick** · July 16, 2009, 05:18 PM

The rebound or spring-back is key. If you are resizing a case slightly it can be harder to make a difference than if you are setting it back a lot and the case has to push the brass past its yield. I've had Lake City .30-06 fired in different guns that varied about 0.003" to 0.005" in length from the head to the shoulder coming out of the same sizing die.

I suppose the small base dies could be changing. Older shooters will recall the early benchrest shooters often just had a machine shop use a surface grinder to take a couple thousandths off the to of their shell holder. If the change had to be in the die to be able to port the die between presses, they would grind it off the end of the die. More than one way to skin that cat, I guess?

F. Guffey · July 17, 2009, 08:50 AM

There is something reloaders never learned to do and that is 'verify', Adjust the die down to the shell holder with the ram up, lower the ram and then add a 1/8, 1/4 or 1 full turn (depends on how mad they are at their press) then size a case, what do they get? They do not know, it is full length or a guesstimate.

Automotive feeler gage? I have never seen an automotive feeler gage that included gages between .001 and .010, most start at .010, I like automotive feeler gages, some include wire gages, when purchasing a feeler gage for guns ( reloaders should get instructions) make sure the gage starts at .001, some start at .0015 and has every gage up to .020.

Forget the neck thickness, reaming and turning, you need practice to build confidence.

I purchased 1.400 cases for .01 cent each, $14.00 for 1,400 30/06 cases, once fired, everyone passed on them, I purchased another 800 linked 30/06 cases for $30.00 with no intentions of ever loading them as 30/06 cases. The shoulder on the 30/06 is .394 further out than the 308 W, the shoulder on the 8X57 Mauser is further .273 out than the 308 W, or put another way the length from the head of the case from the head to datum (circle round hole) is shorter on the 308 W that the 30/06 or 8MM Mauser, datum (round hole/circle) on the 30/06 is .375 and the 308 W is .004.

Start with forming 40 cases, use a few, save the rest when the press can be trained to produce predictable results, I will size the cases with different case length from the shoulder to the head of the case to test chamber length, again without the intentions of loading the test cases, more time than not I will drill the flash hole/primr pocket and use the cases for max. OAL gages.

I use a case forming/trim die to form 308 cases using 30/06 cases with a ..010 gap between the shell holder and bottom of the die (this guarantees me the cases will not chamber until the cases are full length sized) I then use a hack saw to trim the case before lowering the ram (If I thought the case had a memory of being a 30/06 case I would lower the ram 'hesitate' then raise the ram again and use a file to trim again)

After forming I would full length the cases to 308 W with a .010 gap between the shell holder and bottom of the die, after checking case length for trim the cases should not chamber, then I would reduce the gap between the top of the shell holder and bottom of the die, a gap of .005 would be a good start, after sizing the cases should not chamber or chamber with resistance, resistance would indicate the chamber has .005 head space, if the case chambers without resistance, the head space should be suspect, if suspect increase the gap to .008 thousands and try again.

I form 257 Roberts, 7X57, 8X57 etc from 30/06 cases, Wildcats and anything that has a shoulder ahead of the 30/06 I use the 280 Remington, .041 longer with a shoulder .051 further out than the 30/06.

Again, it is not necessary to grind the bottom of the die or top of the shell holder, it is not necessary to purchase Redding special shell holders, anything grinding or Redding shell holders will accomplish the reloader shoulder be able to duplicate with a machinist feeler gage, anything over .010 can be accomplished with a mechanics feeler gage.

Verify the results? I could not afford the tools so I made the tools.

July 15, 2009, 03:55 PM	#1
tjndaltx Junior Member Join Date: September 14, 2007 Posts: 6	Head space gage for 308 I'm trying to use a Dillon headspace gage to set my die to the correct depth. No matter what I do I cannot get the set the shoulder at the correct point for the case head to lie below the high point on the gage. I have the die in so far the rings will not even connect with the threads on the die. Obviously, I'm doing something wrong here. Should I trim my cases to length before using the sizing die with the headspace gage? Any ideas on what might be wrong? Help!!!

July 15, 2009, 04:26 PM	#2
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,093	Welcome to the forum. What press and what die are you using? Watch this Lee help video for setting one of their rifle sizing dies up. It is the way all standard sizing dies are set up. Did you read the cartridge name on the side of the die and does that name match the cartridge you are trying to load? I know that sounds foolish, but you'd be surprised how common it is for people to be mislead into thinking there is no difference between rounds whose name starts with the same number, like .300 or 7.62, when in fact there are dozens of rounds with drastically different case shapes whose names start with the same characters as some others, so it is worth checking. Did you follow instructions for getting the decapper and expander ball stem correctly adjusted? If not, they can prevent the case from entering the die completely. One last thing: are the cases from rounds you fired in the same gun you are loading for? If so, and that gun has a long chamber, it could be difficult to set the shoulder back 100%, but it will still fit in that same long chamber just fine. You generally only need to meet the gauge numbers if you are going to fire the ammo in different guns. There are a few exceptions: auto-loading rifles sometimes need original case sizing. If the cases are long, such as once-fired surplus, it can occasionally be necessary to buy a special extra-small sizing die called a small base die, which knocks the shoulders back an extra couple of thousandths. If you have a press that uses standard shell holders, you can also get a couple of thousandth ground off the top of the holder so the die can be set up closer to the case head. You can also usually get an extra two or three thousandths off the shoulder by raising the case up into the die, counting to five, withdrawing it and letting it rest outside the die for another count of five, then running it back up into the die again for a second count of five. This is a temporary remedy while you wait for your small base die to arrive or while you are working on taking a little metal off the top of the shell holder. It is not a good permanent solution because it makes you size and expand the neck twice for each loading, and that will harden it prematurely, and unless you learn to anneal your case necks, that will shorten case life. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle Last edited by Unclenick; July 15, 2009 at 04:35 PM.

July 15, 2009, 05:37 PM	#4
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,093	Removing the decapper also removed the expander. The problem for the die maker is that SAAMI specs case walls for a tolerance of 0.004" thickness (max OD over the bullet, -0.008", which includes two wall thicknesses). The problem then is how to size the neck so the ID of the case mouth fits the bullet? A thick neck will size the hole too small, while a thin one might leave a loose fit. So what they do is cut the die to size the thinnest neck in the tolerance range, which leaves the inside of the neck about 0.008" too small if a case has the maximum wall neck. To get the neck ID the right size to accept and hold the bullet regardless of how small it came out of the die, they force it to pass over that expander. So, chances are, without the expander you have necks that are too narrow for best bullet tension and some will crush the shoulder when you try to load them. Since you have your decapper out of the die anyway right now, before putting it back and getting a small base die, try sizing a case with a 0.002" automotive feeler gauge slipped in under the case head. That will raise it enough so the standard die makes it the same shoulder-to-head length that a small base die will. See if that's enough for what you are trying to do? __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

July 16, 2009, 05:18 PM	#11
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,093	The rebound or spring-back is key. If you are resizing a case slightly it can be harder to make a difference than if you are setting it back a lot and the case has to push the brass past its yield. I've had Lake City .30-06 fired in different guns that varied about 0.003" to 0.005" in length from the head to the shoulder coming out of the same sizing die. I suppose the small base dies could be changing. Older shooters will recall the early benchrest shooters often just had a machine shop use a surface grinder to take a couple thousandths off the to of their shell holder. If the change had to be in the die to be able to port the die between presses, they would grind it off the end of the die. More than one way to skin that cat, I guess? __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

July 15, 2009, 05:15 PM	#3
tjndaltx Junior Member Join Date: September 14, 2007 Posts: 6	Hi Unc Nick again, I'm using a Redding T-7 turret press with Lee dies. Not stupid. But my die is a 308 Winchester. "Did you follow instructions for getting the decapper and expander ball stem correctly adjusted? If not, they can prevent the case from entering the die completely." I removed the decapper from the die since there are no primers in the cases. Guess I could have left it in but I didn't. Did I goof there? These rounds will be fired in different guns. One a bolt the other a semi-auto. Maybe I should buy the small base die?

July 15, 2009, 05:43 PM	#5
tjndaltx Junior Member Join Date: September 14, 2007 Posts: 6	I don't know that I have a feeler gauge, so may have to pick one up tomorrow. But I'll sure try it. Thanks for the explanation. I bought the 308 die set used and I regret that. I'm going to buy a new set along with the small base die.

July 15, 2009, 06:05 PM	#6
Slamfire Senior Member Join Date: May 27, 2007 Posts: 5,261	What you describe is most unusual. I have a set of Dillion 30-30 dies and they set up properly on my Redding T-7. If you have screwed the die so far down in the turret head that the threads of the die are below the turret head, something is obviously wrong. Does the bottom of your die touch the shell holder when the ram is raised? If the die is in fact touching the shell holder, than it is futile to screw the die any more through the turret head. It is futile because the die body is too long. Once you touch the shell holder, and the shoulder is not being moved back, well you can't shorten that distance any more by raising or lowering the die. One way to shorten the distance from the bottom of the die, and the shoulder inside the die, is to remove material from the bottom of the die. This shortens the die. Wish I could see a picture of what you are doing, because I am guessing this is your problem.

July 15, 2009, 06:20 PM	#7
jepp2 Senior Member Join Date: December 24, 2008 Location: Loveland, CO Posts: 1,476	I have a Lyman die (.223 Remington), that I tried everything Unclenick recommended, and I never could get the shoulder set back enough to properly size the brass. I have headspace gauges (the true male headspace gauge) and I could confirm that indeed the shoulder wasn't being set back enough. I switched to a Redding die set, rather than remove height from my shell holder. So there are some dies that just will not set the shoulder back adequately.

July 15, 2009, 06:45 PM	#9
tjndaltx Junior Member Join Date: September 14, 2007 Posts: 6	Unc Nic, The small base die, is that the sizer die that sets the shoulder back a little further than the normal die?

July 16, 2009, 10:48 AM	#10
Slamfire Senior Member Join Date: May 27, 2007 Posts: 5,261	Maybe I should not be answering this, but old small base dies would set the shoulder back so much, you could/would get case head separations. Very few people use cartridge headspace gages to set up their dies, so you will hear, time and time again, "small base over work brass". And this is due to these folks just setting a small base die to the shell holder "plus a quarter turn". However even reloading companies learn to protect us from our ignorance. I purchased a new RCBS small base X die in 308. With the die touching the shell holder, it will not size brass any shorter than gage minimum. Something has changed. This is in fact a problem as cases do not rebound the same. Depending on the rifle it was fired in, (like my FAL) and depending on the work hardening of the cases, there have been times I have had to set the small base down below “gage minimum”. Well gage minimum for the average 308 I own. Now I can’t unless I remove material from the bottom of the die.

July 17, 2009, 08:50 AM	#12
F. Guffey Senior Member Join Date: July 18, 2008 Posts: 7,249	There is something reloaders never learned to do and that is 'verify', Adjust the die down to the shell holder with the ram up, lower the ram and then add a 1/8, 1/4 or 1 full turn (depends on how mad they are at their press) then size a case, what do they get? They do not know, it is full length or a guesstimate. Automotive feeler gage? I have never seen an automotive feeler gage that included gages between .001 and .010, most start at .010, I like automotive feeler gages, some include wire gages, when purchasing a feeler gage for guns ( reloaders should get instructions) make sure the gage starts at .001, some start at .0015 and has every gage up to .020. Forget the neck thickness, reaming and turning, you need practice to build confidence. I purchased 1.400 cases for .01 cent each, $14.00 for 1,400 30/06 cases, once fired, everyone passed on them, I purchased another 800 linked 30/06 cases for $30.00 with no intentions of ever loading them as 30/06 cases. The shoulder on the 30/06 is .394 further out than the 308 W, the shoulder on the 8X57 Mauser is further .273 out than the 308 W, or put another way the length from the head of the case from the head to datum (circle round hole) is shorter on the 308 W that the 30/06 or 8MM Mauser, datum (round hole/circle) on the 30/06 is .375 and the 308 W is .004. Start with forming 40 cases, use a few, save the rest when the press can be trained to produce predictable results, I will size the cases with different case length from the shoulder to the head of the case to test chamber length, again without the intentions of loading the test cases, more time than not I will drill the flash hole/primr pocket and use the cases for max. OAL gages. I use a case forming/trim die to form 308 cases using 30/06 cases with a ..010 gap between the shell holder and bottom of the die (this guarantees me the cases will not chamber until the cases are full length sized) I then use a hack saw to trim the case before lowering the ram (If I thought the case had a memory of being a 30/06 case I would lower the ram 'hesitate' then raise the ram again and use a file to trim again) After forming I would full length the cases to 308 W with a .010 gap between the shell holder and bottom of the die, after checking case length for trim the cases should not chamber, then I would reduce the gap between the top of the shell holder and bottom of the die, a gap of .005 would be a good start, after sizing the cases should not chamber or chamber with resistance, resistance would indicate the chamber has .005 head space, if the case chambers without resistance, the head space should be suspect, if suspect increase the gap to .008 thousands and try again. I form 257 Roberts, 7X57, 8X57 etc from 30/06 cases, Wildcats and anything that has a shoulder ahead of the 30/06 I use the 280 Remington, .041 longer with a shoulder .051 further out than the 30/06. Again, it is not necessary to grind the bottom of the die or top of the shell holder, it is not necessary to purchase Redding special shell holders, anything grinding or Redding shell holders will accomplish the reloader shoulder be able to duplicate with a machinist feeler gage, anything over .010 can be accomplished with a mechanics feeler gage. Verify the results? I could not afford the tools so I made the tools.