Gunsmithing Setting headspace; how tight is too tight?

[BurnOut]

I'm pretty sure I know the answer here (as long as the bolt rotates open/closed smoothly on the GO gauge, you're in good shape), but want to be certain. Long story short, yesterday I installed a barrel using a Bugnut, and set the headspace such that the GO gauge fits well and bolt handle feel is good, but when I made my makeshift NO GO gauge (a piece of .0015 packaging tape on the back of the GO gauge) the bolt barely even starts to close before I get excessive resistance. So, to me, that means that the headspace is close to minimum... perhaps .0005-.001 over.

I checked a handful of factory loaded rounds, and they all chambered just fine. Because the feel with the GO gauge is good and the factory loaded ammo fits, I'm assuming that I'm in good shape, but wanted to check with the collective wisdom of the Hide.

So, what say ye? Too tight, or just right?

 

[Huskydriver]

If your bolt partially closes on a no-go, it's loose not tight but doesn't mean it's not safe. You have your chamber set up on the max side of things not the min.

If it's a bench rest style gun, I prefer to set my headspace up tight to maximize brass life but if reliability is more of a priority I prefer to set the hs on the loose side so that all rounds will chamber fine.

If it was too tight, a factory round loaded to max potentially wouldnt chamber easily.

 

[BurnOut]

If your bolt partially closes on a no-go, it's loose not tight but doesn't mean it's not safe. You have your chamber set up on the max side of things not the min.

I appreciate the reply. Looking at the specs for the proper NO GO gauge for this cartridge (6mm Creedmoor), it looks like the NO GO spec is .004 longer than the GO; given that my makeshift NO GO was only .0015 longer than GO and the bolt barely starts to close on it, that's why I'm wondering if it's too tight. I can only assume that if I were to use a proper NO GO, that the bolt wouldn't even attempt to close.

In any event, though, it sounds like I'm in good shape... this is a hunting-oriented build in a (relatively) easily found chambering; so while I don't want to beat up brass unnecessarily, I'm also not going to have hours of prep time in unobtainium cases (read: if I only get 5 reloads out of a single case instead of 7 or 10, I'm not going to lose sleep over it).

Thanks again for the feedback.

 

[Steel head]

I set mine up to close on a go gauge and not close on same gauge with .002 tape on back of it.

If factory ammo doesn’t fit that it’s the ammo not the chamber.

Doing this promotes brass lasting a long time.

Most no go’s are .0035-006. larger depending on the case and spec used.

 

[Huskydriver]

I appreciate the reply. Looking at the specs for the proper NO GO gauge for this cartridge (6mm Creedmoor), it looks like the NO GO spec is .004 longer than the GO; given that my makeshift NO GO was only .0015 longer than GO and the bolt barely starts to close on it, that's why I'm wondering if it's too tight. I can only assume that if I were to use a proper NO GO, that the bolt wouldn't even attempt to close.

In any event, though, it sounds like I'm in good shape... this is a hunting-oriented build in a (relatively) easily found chambering; so while I don't want to beat up brass unnecessarily, I'm also not going to have hours of prep time in unobtainium cases (read: if I only get 5 reloads out of a single case instead of 7 or 10, I'm not going to lose sleep over it).

Thanks again for the feedback.

Yep misread your op about your tape. You are correct that your set up on the tight side of HS but safe.

 

[Rubicon Precision]

The bottom line is if the bolt drops on a go gauge, any in spec ammo will fit.
Edit: I should say any in spec brass will fit.

 

[Snuby642]

Been measuring factory 223, 308, 300blk of various brands, some 5.56 and 7.62 nato.

Have found every one of them to be very short, to the extreme.

I have found none on the large side and a couple that would not load were obviose dammage had occured.

Am I just lucky?

 

[Wannashootit]

Brass fits the chamber and the bolt closes with light resistance at the bottom is perfect for me.
Point being, it's really the brass and your rifle's chamber, and their datum length that determines headspace and hence brass life, etc.

Headspace gauge is necessary (especially if factory ammo ), but you can have a chamber that might have "excessive" headspace by SAAMI standards with a headspace gauge- but still might be perfectly fine for a handloader that sets his sizing die to fit his chamber.

 

[XLR308]

Been measuring factory 223, 308, 300blk of various brands, some 5.56 and 7.62 nato.

Have found every one of them to be very short, to the extreme.

I have found none on the large side and a couple that would not load were obviose dammage had occured.

Am I just lucky?

It's been my experience that Nosler brass and ammo in some calibers runs a little longer on headspace than others but is within SAAMI spec.
I set my 243win to min headspace and only Nosler ammo had slight restistence on closing the bolt.

 

[Deleted member 10043]

Lose your no go?

 

[antithesis]

Brass fits the chamber and the bolt closes with light resistance at the bottom is perfect for me.
Point being, it's really the brass and your rifle's chamber, and their datum length that determines headspace and hence brass life, etc.

Headspace gauge is necessary (especially if factory ammo ), but you can have a chamber that might have "excessive" headspace by SAAMI standards with a headspace gauge- but still might be perfectly fine for a handloader that sets his sizing die to fit his chamber.

This, but also check your sizing die. You can set headspace to where a piece of new, unfired brass closes with little or no resistance, or sized brass that you ran the die down to the shell holder on only to find your die will not reach the shoulder after firing or cannot set the shoulder back which will result in the inability to size most of the neck (may or may not be a problem depending on your bullet seating depth) and eventually will result in heavy lifting of the bolt. I recently installed a barrel and realized I did not have any unsized brass to size down to where I wanted them and then set the headspace with that brass. Chances are I will need to adjust the headspace to make sure I am getting the shoulder bump I am looking for after sizing because of this error. So yeah, you can have a Go gauge close easily and still be too tight.

 

[clcustom1911]

As far as "excessive" headspace goes... when I did my prefit Proof Research Barrel to my RPR (6.5 Creedmoor) the Proof techs advised me to do minimum headspace +.003" to make sure all factory ammo would fit across the board.

 

[Bugholes]

if I was setting up a barrel nut barrel, I would be doing more like go + .002-.003, especially in a creedmoor.Ive seen plenty of [6.5] Creedmoor brass that was at max or even a little over
use a post-it note instead of a thin piece of tape. by the time you feel resistance youre smashing the tape and may be at closer to GO plus very very little. if your chamber was at go +.003 for example youd barely feel any compression on your .003 "shim" put on between the bolt face and HS gauge, not the moderate resistance youre describing. HS essentially has nothing to do with accuracy

 

[B y r o n]

Am I missing something here? Bolt closes on a Go gauge but not on a No-Go gauge. This should be the end of the story, as there should be no issues. Go gauge is set to just over SAAMI maximum chamber length.

 

[antithesis]

Am I missing something here? Bolt closes on a Go gauge but not on a No-Go gauge. This should be the end of the story, as there should be no issues. Go gauge is set to just over SAAMI maximum chamber length.

I have found that closing on the go alone does impact case expansion. If you have a saami gauge and a saami die and both are the same you cannot set the shoulder back. If you want a little more case capacity you can run a little more headspace and expand on the first firing, then set back to whatever you want from that point forward. That is why i check with a case that has already been fired but not sized as well as go/no-go.

 

[Deleted member 10043]

Am I missing something here? Bolt closes on a Go gauge but not on a No-Go gauge. This should be the end of the story, as there should be no issues. Go gauge is set to just over SAAMI maximum chamber length.

Their trying things without a no go gauge. Not sure I'm following either

 

[antithesis]

Their trying things without a no go gauge. Not sure I'm following either

What is being said is that we use both, but recognize that a close on a go can still be too tight for certain applications so we find a spot in the middle.

 

[Rubicon Precision]

What is being said is that we use both, but recognize that a close on a go can still be too tight for certain applications so we find a spot in the middle.

If the bolt drops on the go gauge and some brass doesn’t fit due to length, either the brass is out of spec or the gauge is. Same thing if you can’t resize brass short enough. Either the die is out of spec or the HS gauge is.

 

[DAVETOOLEY]

If the bolt drops on the go gauge and some brass doesn’t fit due to length, either the brass is out of spec or the gauge is. Same thing if you can’t resize brass short enough. Either the die is out of spec or the HS gauge is.

I'll add that what some call a misfit between new brass and a chamber can usually be attributed to the shoulder/neck junction. Each will have a different radius and at times starts out with a slight interference fit which promptly disappears on the first firing.

 

[Eddystone]

One thing that can affect this dimension with reloading is a tolerance stack in the dies and shell holder. Mismatched brands bit me once. If new brass, well disregard.

 

[Red_SC]

If the bolt drops on the go gauge and some brass doesn’t fit due to length, either the brass is out of spec or the gauge is. Same thing if you can’t resize brass short enough. Either the die is out of spec or the HS gauge is.

This. The chamber and the brass both have a tolerance range, but max on the brass is smaller than min on the chamber unless it’s something like an Ackley that uses crush. If the go gauge fits without force and is in spec, the brass is out of spec.

 

[Dolomite_Supafly]

I reload everything I shoot and will never shoot factory ammunition. When I set my headspace I do not use headspace gauges, I use brass that was sized on my equipment. I generally set my headspace between zero and .002" of clearance using my sized brass.

I use a hole punch to punch out a small pieces of paper for setting/checking headspace. If I want some clearance I drop the paper circle onto the bolt face then tighten the barrel down on the piece of sized brass.