.30-06 info

[milboltnut]

Is .004 HS too much in my M70 ? I start with 2.046 and have to size to 2.042. Funny the NG gauge is 2.046 and doesn't come close to the bolt closing and the go gauge is 2.042 which the bolt has very slight resistance on closing.

Is the 06 hard to deal with HS wise ?

[Parashooter]

Quiz -
HeadspaceCquiz.jpg

Answer -
HeadspaceC.jpg

"Is .004 HS too much in my M70 ?" Hard to answer if you really mean "HeadSpace, but .004" end-play is no problem

[bruce]

Ammunition has to be produced to fit the smaller end of commercial chambers. Chambers have to be cut by commercial manufacturers to accommodate rounds within the range of allowable tolerances. No commercial round will give a reliable gauge of head space. Only depend on quality head space gauges for such decisions. If the bolt will close on the go-gauge ... fine! If the bolt will close on the no-go gauge ... not good at all! Remove the rifle from service until a qualified gun smith can correct the head space. Sincerely. bruce.

[milboltnut]

Ammunition has to be produced to fit the smaller end of commercial chambers. Chambers have to be cut by commercial manufacturers to accommodate rounds within the range of allowable tolerances. No commercial round will give a reliable gauge of head space. Only depend on quality head space gauges for such decisions. If the bolt will close on the go-gauge ... fine! If the bolt will close on the no-go gauge ... not good at all! Remove the rifle from service until a qualified gun smith can correct the head space. Sincerely. bruce.

I already know that bro, but thanks!

[milboltnut]

Found this explanation on another forum

On a new chamber the difference between is measured with Go and No Go gauges. The difference between these two gauges is generally accepted to be .004" from min to max.

I measured the high and low step on my case head space gauge and there's .004 difference, big surprise huh !

Also I would say chamber concentric to the bore is important, the case being non-linear shoulder angle can create a problem chamber problem.

[fguffey]

Is .004 HS too much in my M70 ?

No, .004" is not enough but if we are talking about clearance? .004" clearance is perfect. I have a M1917 with a chamber that is long; the chamber is .002" longer than a field reject length gage. That means nothing to most but when I fire a minimum length case in the field gage length +.002" chamber I have .016" clearance. I do not wonder what happened to all of the ammo fired in my rifle before I measured the length of the chamber.

And then I ask about a 30/06 chamber that .011" longer than a go-gage length chamber; is the chamber in my M1917 too long?

F. Guffey

[milboltnut]

Definitely dizzy after your post Guffey. Max SAMMI is 2.058 and minimum is 2.048. Explain clearance verses HS. And did you do a chamber cast to know the length of your 1917 ?

[fguffey]

Milboltnut, forgive, I do not normally check to determine who is active on a thread, hello.

F. Guffey

[milboltnut]

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.


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.

How do you know the latter ?

[lyman]

guffey is a bit hard to read and understand sometimes, but once you learn his style, he is usually correct on headspace,

I think he sees it from another angle so to speak,



meanwhile, re the .04

USGI gauges are 1.940, 1.946, and field is 1.950


one a bolt gun, simply measure our fired cases, and throat, and adjust your dies to load to fit,

[fguffey]

Explain clearance verses HS. And did you do a chamber cast to know the length of your 1917?

You ask this question of one of only two reloaders that can measure a chamber for head space/length of a chamber, thank you.

No, for me it was easier to measure the length of the chamber from the shoulder of the chamber to the bolt face. The 280 Remington case is .051" longer than the 30/06 case from the shoulder to the case head. When it comes to forming cases I cannot miss with .051". long story to make you dizzy, when measuring long chamber, I use a forming die with a feeler gage to adjust the die off of the deck of the shell holder. After forming/sizing I measure the length of the case from the datum (.375") to the case head for final adjustment.

After I make final adjustments, I adjust the die to .014"off the deck of the shell holder, the .002" gives me .002" clearance on my newly formed/sized cases.

F. Guffey

The length of my chambers is measured in thousandths.

Component manufactures do not manufacture cases to reloaders that know what they are doing, if they did, they would add a few thousandths to the case between the datum/shoulder to the case head.

[milboltnut]

that's what I did...but am getting caught up in .001 to .002 bump, but a guy told me that the 06 has issues with the shoulder verses the improved shoulder.

- - - Updated - - -

You ask this question of one of only two reloaders that can measure a chamber for head space/length of a chamber, thank you.

No, for me it was easier to measure the length of the chamber from the shoulder of the chamber to the bolt face. The 280 Remington case is .051" longer than the 30/06 case from the shoulder to the case head. When it comes to forming cases I cannot miss with .051". long story to make you dizzy, when measuring long chamber, I use a forming die with a feeler gage to adjust the die off of the deck of the shell holder. After forming/sizing I measure the length of the case from the datum (.375") to the case head for final adjustment.

After I make final adjustments, I adjust the die to .014"off the deck of the shell holder, the .002" gives me .002" clearance on my newly formed/sized cases.

F. Guffey

The length of my chambers is measured in thousandths.

Component manufactures do not manufacture cases to reloaders that know what they are doing, if they did, they would add a few thousandths to the case between the datum/shoulder to the case head.

So do I. I don't think you realize you are setting the shoulder back

ANd yeah you continue to make me dizzy and your mod says you do to.

[fguffey]

Head space and clearance: For years reloaders claimed the case had head space, my cases have a length, I off set the length of the chamber with the length of the case.

I measure the length of my cases from the datum to the case head, If I want to know the clearance between the bolt face and case head I have to have a way to measure the length of the chamber (head space).

F. Guffey

[milboltnut]

Head space and clearance: For years reloaders claimed the case had head space, my cases have a length, I off set the length of the chamber with the length of the case.

I measure the length of my cases from the datum to the case head, If I want to know the clearance between the bolt face and case head I have to have a way to measure the length of the chamber (head space).

F. Guffey

And what way is that ?

[fguffey]

that's what I did...but am getting caught up in .001 to .002 bump, but a guy told me that the 06 has issues with the shoulder verses the improved shoulder.

There is the chamber shoulder and there is the case shoulder. And I have found it impossible to move a shoulder back, I cannot move the shoulder of a case back and I cannot bump it back.

For years reloaders have talked about the dreaded donut and then they claim they "move the shoulder back", if they could move the shoulder back, they could eliminate the dreaded donut.

F. Guffey

F. Guffey