Proper Headspace

Stats Shooter · February 9, 2017, 11:48 PM

So I am doing my first Savage 110 rebarrel job on my .300 win mag. I have the fosters go and no go belted mag gauges. I know it headspaceing off the belt. I also hand load for this gun, and many other guns.

So my question is, how tight do y'all like the chamber to be on the the go gauge? Just barely able to close? Easily able to close on the go gauge but not on the no go?

In my case, the only time a cartridge will headspace on the belt is with virgin brass... Because once fired they will space of the shoulder/datum as I neck size after that. But I want a saami spec chamber or I would just headspace on a sized piece of brasses shoulder in the first place.

My initial thoughts are to make it tight so the brass grows the least, Which is inevitable on a .300 wm (they can grow as much as .020 in a saami spec chamber). But I just wanted some opinions on this topic.

Thanks for any replies.

taylorce1 · February 10, 2017, 12:37 AM

Headspace off the belt like your gauges are supposed to. When I set up a Savage barrel I use both go and no-go gauges, the bolt closes with no resistance to speak of on the go gauge. However, if my bolt closes more than half way on the no-go gauge, I tighten the headspace up.

After that when you resize your once fired case set up your die so it doesn't bump the shoulder back, or very minimally as needed. This should give you the max life out of your brass. You might run into problems with your case head expanding too much at the belt making it hard to chamber, but there is a die to resize that as well.

Stats Shooter · February 10, 2017, 12:43 AM

Quote:

. You might run into problems with your case head expanding too much at the belt making it hard to chamber, but there is a die to resize that as well.

I am aware of this issue, but in 6 yrs reloading for the .300 wm I have not had a problem. All I have done is neck size and after a few loads FL sized ...But not with any special collet die. All I used was RP brass too, nothing high end.....Easy sub moa.

But I do intend to use the gauges, like you said.....That's why they exist. But your saying not terribly snug on the go gauge.

Gunplummer · February 10, 2017, 05:01 AM

Here we go again.

taylorce1 · February 10, 2017, 08:39 AM

No, I'm not saying loose headspace at all. No resistance was probably the wrong term. I don't want it to close any harder than any other bolt action rifle that I own that is known to have proper headspace.

Just make sure it closes on the go gauge and doesn't on the no-go. My preference is if the bolt rotates more than 45 degrees on a Savage with the no-go gauge is to screw the barrel in. It won't take much, and If you have to tighten the headspace recheck with the go gauge. Your gauges will tell you everything you need to know.

5whiskey · February 10, 2017, 09:02 AM

Quote:

I also hand load for this gun, and many other guns.

If this is the case, then just worry about this...

Quote:

Just make sure it closes on the go gauge and doesn't on the no-go.

That's all you need. If you were shooting factory ammo only, you may would want to get the headspace as tight as possible (to reliably feed) for accuracy purposes. Since you handload, and this is a belted magnum to boot, you will be able to control some of your headspace and freebore with your sizing die at the reload press. All you really need is it to be within spec to reliably chamber factory ammo if you ever have to buy any in a pinch.

Jim Watson · February 10, 2017, 09:24 AM

I have not done this but twice, so take it with a grain of salt.
I don't own a no-go gauge.
I screwed the barrels in snug against the Go and tightened the nut.
Shoot.
No case head separations yet.

Your chamber is already cut, your head-to-shoulder dimension which would be the headspace control measurement in a rimless caliber is fixed. Actually your belt recess dimension is fixed, you are talking about a slight tweak with the gauges. You say you will neck size so you will then be operating in rimless mode and the belt serving no purpose.

5whiskey · February 10, 2017, 09:49 AM

Quote:

I screwed the barrels in snug against the Go and tightened the nut.

I have done the same and it works fine. I have also used a factory round (trust me, I removed the firing ping from the bolt

) as a go gauge in a pinch. Using the round worked, but it's not ideal as it could be on one extreme or the other of the spec range. I don't really recommend the method to folks because it isn't "textbook."

Stats Shooter · February 10, 2017, 10:27 AM

Quote:

That's all you need. If you were shooting factory ammo only, you may would want to get the headspace as tight as possible (to reliably feed) for accuracy purposes. Since you handload, and this is a belted magnum to boot, you will be able to control some of your headspace and freebore with your sizing die at the reload press. All you really need is it to be within spec to reliably chamber factory ammo if you ever have to buy any in a pinch.

That is kind of what I thought.....Good enough, then, close on the go, don't close in the no go, then I'll just fire form the brass and move on.
Thanks

T. O'Heir · February 10, 2017, 12:37 PM

Just barely able to close on a Go means insufficient headspace. The bolt should close easily on the Go and not at all on the No-Go. Even a little "open" is ok with a No-Go.
Headspace has nothing whatever to do with accuracy. It's a rifle manufacturing tolerance only.

Stats Shooter · February 10, 2017, 12:41 PM

Quote:

Just barely able to close on a Go means insufficient headspace. The bolt should close easily on the Go and not at all on the No-Go. Even a little "open" is ok with a No-Go.
Headspace has nothing whatever to do with accuracy. It's a rifle manufacturing tolerance only.

Thanks T. Oheir.. by the way, what is the usual tolerance between the go and no go on a belted magnum? I know the only saami spec gauges are the go and the field gauge so the no go may be gauge maker specific.but was just wondering what the difference was....003? .004?

Jim Watson · February 10, 2017, 12:49 PM

I think .007" max to min.

A minimum chamber must take a maximum round but somebody once posted here that no belted case he measured was much above minimum. I see no reason not to set it tight, especially for.a handloader working with one lot of brass.
If you were buying a box at a time from the General store, it would be smart to go for mid-spec.

Nice thing about a Savage, if you don't like what you have to start, it is simple to adjust.

mete · February 10, 2017, 07:54 PM

IIRC , General Hatcher [Hatcher's Notebook ] his tests showed that in rapid firing a 1903 ,where a good bit of force occurs , it could set back the shoulder .006" ! Just sayin' .
I set my rifles to minimum. When I was shooting 45 acp I never found cases that were max or more so I never had to trim that case !!

RC20 · February 11, 2017, 12:39 PM

It really does not matter! (well some but only if you go way out)

After your first firing, you have a fire formed case and you are going to measure that shoulder, bump it back your minimum and then its the same forever (more or less)

As long as your new brass fits (factory load or not) then you are fine.

Now, if you set it loose on a no go, then it has to grow a lot to fire form.

So anywhere from a easy close on the go to a tight close or no close on the no go works.

Now if its being shot in different rifles, that is different.

Stats Shooter · February 12, 2017, 03:01 PM

The factory barrel is still on the rifle. I finally got the Fosters gauges in the mail. So before taking the factory barrel off, I checked the headspace for reference.

Bye the way, the fosters gauges had a .2200" base to top of the belt measurement (which is exactly SAAMI minimum headspace on belted mags). And a measurement for the same base to top of belt on the No-go of .2240".....So 4 thousandths difference.

Of course I first removed the extractor, then I found that the factory installed barrel closed easily on the go gauge with virtually no resistance. And closed about 1/2 way on the No-go. Keep in mind that I have about 1400 rounds down the factory barrel also....But it is still pretty much perfectly headspaced.

Anyway,
Thanks for all the information. I plan to try get similar results when I put the new barrel on.

James K · February 12, 2017, 04:42 PM

Once headspace in a rifle is set, it is unlikely to change through any change in the barrel or chamber. What changes is the bolt lug seat and/or the bolt lugs battering each other as the cartridge presses backward against the bolt. In a well designed rifle, the barrel will be ruined from erosion and wear long before either the bolt lugs or the seats are damaged enough to matter and when that happens, the receiver is scrap. But we are talking about (usually) tens of thousands of rounds and years of use.

Jim

ShootistPRS · February 12, 2017, 08:49 PM

It is really gratifying to see the expertise in this discussion.

RC20 · February 13, 2017, 04:55 PM

Serious mis understanding of head space.

Head space is to the shoulder from the rear case.

Firing the gun eats out the throat and you have to seat bullets longer, but does not affect head space.

Stats Shooter · February 13, 2017, 05:41 PM

Quote:

Serious mis understanding of head space.

Head space is to the shoulder from the rear case.

Actually, in a belted magnum, SAAMI headspace is set on the belt. From the base of the case to the top of the belt. Some people do headspace their belted magnums from the shoulder, (I do after the case has been fireformed to my chamber), but the go/ no-go gauges are from the base to top of belt. In this particular thread I was referencing my .300 win mag.

As for the headspace not changing, I know that it isn't supposed to change, but I have heard that if you load your rounds hot, you can bend lugs or wear on your boltface. Maybe that is just madeup B.S. but I have heard that said before.

Not trying to be rude or disrespectful here, just pointing out an exception to the head space measurement standard.

RC20 · February 13, 2017, 07:29 PM

Woops, forgot it was a belted magnum.

Been some discussion on if the magnum really headspace on the belt.

Now I have to think about it and my head hurts already!

Good discussions on belted on this link

http://www.larrywillis.com/answers.html

Stats Shooter · February 13, 2017, 07:42 PM

Quote:

Been some discussion on if the magnum really headspace on the belt

From talking to some gunsmiths, and my own experience, the answer is yes AND no. A factory loaded SAAMI spec round in my old chamber grew about .015 in length at the shoulder....And almost that amount if I FL sized the case all the way down until my base touched the die.

So when I neck sized Wich didn't really impact the shoulder, then it probably headspaced off the shoulder, and or at least it could have.But if the shoulder is .015 from the chamber max shoulder length, then it's headspaceing off the belt.

So essentially, if you are shooting factory ammo, or FL sizing back to SAAMI, then you are on the belt....If not, probably the shoulder.

My OP on this thread though arose because I'm doing my first Savage barrel swap with barrel nut and wanted to know how tight to make the bolt close on the go gauge.

reynolds357 · February 13, 2017, 08:06 PM

In new brass and factory loads, the belted magnum headspaces off the belt. In reloads, it all depends on how it was sized.

RC20 · February 16, 2017, 04:30 PM

Yep to both.

As for the Savage, set it a bit loose on a go gauge.

that is someplace between where the bolt will start to close but not fully.

At that point a Factory round (or new brass) should chamber with no effort.

Your first shot will fire form it. As tight as you can get it will have minim brass stretch on that first shot.

My take is rather than do the neck size thing that will need to be FL sooner or latter anyway, is do a minimum shoulder bump back.

Stats Shooter · February 16, 2017, 08:57 PM

One comment....The factory barrel nut was on pretty darn snug.....Too snug. Specs say 70 ft lbs....that nut was A lot more than 70 ft lbs....I had to use my breaker bar on the barrel nut wrench with the barrel in a vice.

reynolds357 · February 16, 2017, 09:46 PM

The nut being on too tight is the norm, not the exception. One thing I have learned in machinery maintenance is that it often takes a lot more torque to break a bolt than you put on it to set it. I pulled a gear box a while back that I had installed a few years earlier. I torqued the main bolts down to 90. When I was breaking them, I could not break them with a breaker bar, I had to get the 1" drive impact. (app 300 ft lbs torque) They were not rusted. Go figure.

February 9, 2017, 11:48 PM	#1
Stats Shooter Senior Member Join Date: August 26, 2016 Location: North Dakota Posts: 1,636	Proper Headspace So I am doing my first Savage 110 rebarrel job on my .300 win mag. I have the fosters go and no go belted mag gauges. I know it headspaceing off the belt. I also hand load for this gun, and many other guns. So my question is, how tight do y'all like the chamber to be on the the go gauge? Just barely able to close? Easily able to close on the go gauge but not on the no go? In my case, the only time a cartridge will headspace on the belt is with virgin brass... Because once fired they will space of the shoulder/datum as I neck size after that. But I want a saami spec chamber or I would just headspace on a sized piece of brasses shoulder in the first place. My initial thoughts are to make it tight so the brass grows the least, Which is inevitable on a .300 wm (they can grow as much as .020 in a saami spec chamber). But I just wanted some opinions on this topic. Thanks for any replies.

February 10, 2017, 12:37 AM	#2
taylorce1 Senior Member Join Date: November 18, 2005 Location: On the Santa Fe Trail Posts: 8,248	Headspace off the belt like your gauges are supposed to. When I set up a Savage barrel I use both go and no-go gauges, the bolt closes with no resistance to speak of on the go gauge. However, if my bolt closes more than half way on the no-go gauge, I tighten the headspace up. After that when you resize your once fired case set up your die so it doesn't bump the shoulder back, or very minimally as needed. This should give you the max life out of your brass. You might run into problems with your case head expanding too much at the belt making it hard to chamber, but there is a die to resize that as well. __________________ NRA Life Member

February 10, 2017, 08:39 AM	#5
taylorce1 Senior Member Join Date: November 18, 2005 Location: On the Santa Fe Trail Posts: 8,248	No, I'm not saying loose headspace at all. No resistance was probably the wrong term. I don't want it to close any harder than any other bolt action rifle that I own that is known to have proper headspace. Just make sure it closes on the go gauge and doesn't on the no-go. My preference is if the bolt rotates more than 45 degrees on a Savage with the no-go gauge is to screw the barrel in. It won't take much, and If you have to tighten the headspace recheck with the go gauge. Your gauges will tell you everything you need to know. __________________ NRA Life Member

February 10, 2017, 12:37 PM	#10
T. O'Heir Senior Member Join Date: February 13, 2002 Location: Canada Posts: 12,453	Just barely able to close on a Go means insufficient headspace. The bolt should close easily on the Go and not at all on the No-Go. Even a little "open" is ok with a No-Go. Headspace has nothing whatever to do with accuracy. It's a rifle manufacturing tolerance only. __________________ Spelling and grammar count!

February 10, 2017, 07:54 PM	#13
mete Senior Member Join Date: June 14, 2004 Location: NY State Posts: 6,575	IIRC , General Hatcher [Hatcher's Notebook ] his tests showed that in rapid firing a 1903 ,where a good bit of force occurs , it could set back the shoulder .006" ! Just sayin' . I set my rifles to minimum. When I was shooting 45 acp I never found cases that were max or more so I never had to trim that case !! __________________ And Watson , bring your revolver !

February 10, 2017, 05:01 AM	#4
Gunplummer Senior Member Join Date: March 11, 2010 Location: South East Pa. Posts: 3,364	Here we go again.

February 10, 2017, 09:24 AM	#7
Jim Watson Senior Member Join Date: October 25, 2001 Location: Alabama Posts: 18,541	I have not done this but twice, so take it with a grain of salt. I don't own a no-go gauge. I screwed the barrels in snug against the Go and tightened the nut. Shoot. No case head separations yet. Your chamber is already cut, your head-to-shoulder dimension which would be the headspace control measurement in a rimless caliber is fixed. Actually your belt recess dimension is fixed, you are talking about a slight tweak with the gauges. You say you will neck size so you will then be operating in rimless mode and the belt serving no purpose.

February 10, 2017, 12:49 PM	#12
Jim Watson Senior Member Join Date: October 25, 2001 Location: Alabama Posts: 18,541	I think .007" max to min. A minimum chamber must take a maximum round but somebody once posted here that no belted case he measured was much above minimum. I see no reason not to set it tight, especially for.a handloader working with one lot of brass. If you were buying a box at a time from the General store, it would be smart to go for mid-spec. Nice thing about a Savage, if you don't like what you have to start, it is simple to adjust.

February 11, 2017, 12:39 PM	#14
RC20 Senior Member Join Date: April 10, 2008 Location: Alaska Posts: 7,014	It really does not matter! (well some but only if you go way out) After your first firing, you have a fire formed case and you are going to measure that shoulder, bump it back your minimum and then its the same forever (more or less) As long as your new brass fits (factory load or not) then you are fine. Now, if you set it loose on a no go, then it has to grow a lot to fire form. So anywhere from a easy close on the go to a tight close or no close on the no go works. Now if its being shot in different rifles, that is different.

February 12, 2017, 03:01 PM	#15
Stats Shooter Senior Member Join Date: August 26, 2016 Location: North Dakota Posts: 1,636	Checking factory headspace The factory barrel is still on the rifle. I finally got the Fosters gauges in the mail. So before taking the factory barrel off, I checked the headspace for reference. Bye the way, the fosters gauges had a .2200" base to top of the belt measurement (which is exactly SAAMI minimum headspace on belted mags). And a measurement for the same base to top of belt on the No-go of .2240".....So 4 thousandths difference. Of course I first removed the extractor, then I found that the factory installed barrel closed easily on the go gauge with virtually no resistance. And closed about 1/2 way on the No-go. Keep in mind that I have about 1400 rounds down the factory barrel also....But it is still pretty much perfectly headspaced. Anyway, Thanks for all the information. I plan to try get similar results when I put the new barrel on.

February 12, 2017, 04:42 PM	#16
James K Member In Memoriam Join Date: March 17, 1999 Posts: 24,383	Once headspace in a rifle is set, it is unlikely to change through any change in the barrel or chamber. What changes is the bolt lug seat and/or the bolt lugs battering each other as the cartridge presses backward against the bolt. In a well designed rifle, the barrel will be ruined from erosion and wear long before either the bolt lugs or the seats are damaged enough to matter and when that happens, the receiver is scrap. But we are talking about (usually) tens of thousands of rounds and years of use. Jim

February 12, 2017, 08:49 PM	#17
ShootistPRS Senior Member Join Date: January 3, 2017 Posts: 1,583	It is really gratifying to see the expertise in this discussion.

February 13, 2017, 04:55 PM	#18
RC20 Senior Member Join Date: April 10, 2008 Location: Alaska Posts: 7,014	Serious mis understanding of head space. Head space is to the shoulder from the rear case. Firing the gun eats out the throat and you have to seat bullets longer, but does not affect head space.

February 13, 2017, 07:29 PM	#20
RC20 Senior Member Join Date: April 10, 2008 Location: Alaska Posts: 7,014	Woops, forgot it was a belted magnum. Been some discussion on if the magnum really headspace on the belt. Now I have to think about it and my head hurts already! Good discussions on belted on this link http://www.larrywillis.com/answers.html

February 13, 2017, 08:06 PM	#22
reynolds357 Senior Member Join Date: December 10, 2012 Posts: 6,165	In new brass and factory loads, the belted magnum headspaces off the belt. In reloads, it all depends on how it was sized.

February 16, 2017, 04:30 PM	#23
RC20 Senior Member Join Date: April 10, 2008 Location: Alaska Posts: 7,014	Yep to both. As for the Savage, set it a bit loose on a go gauge. that is someplace between where the bolt will start to close but not fully. At that point a Factory round (or new brass) should chamber with no effort. Your first shot will fire form it. As tight as you can get it will have minim brass stretch on that first shot. My take is rather than do the neck size thing that will need to be FL sooner or latter anyway, is do a minimum shoulder bump back.

February 16, 2017, 08:57 PM	#24
Stats Shooter Senior Member Join Date: August 26, 2016 Location: North Dakota Posts: 1,636	One comment....The factory barrel nut was on pretty darn snug.....Too snug. Specs say 70 ft lbs....that nut was A lot more than 70 ft lbs....I had to use my breaker bar on the barrel nut wrench with the barrel in a vice.

February 16, 2017, 09:46 PM	#25
reynolds357 Senior Member Join Date: December 10, 2012 Posts: 6,165	The nut being on too tight is the norm, not the exception. One thing I have learned in machinery maintenance is that it often takes a lot more torque to break a bolt than you put on it to set it. I pulled a gear box a while back that I had installed a few years earlier. I torqued the main bolts down to 90. When I was breaking them, I could not break them with a breaker bar, I had to get the 1" drive impact. (app 300 ft lbs torque) They were not rusted. Go figure. Last edited by reynolds357; February 17, 2017 at 07:38 PM.