• HideTV Updates Coming Monday

    HideTV will be down on Monday for updates. We'll let you all know as soon as it's back up and message @alexj-12 with any questions!

  • Win an RIX Storm S3 Thermal Imaging Scope!

    To enter, all you need to do is add an image of yourself at the range below! Subscribers get more entries, check out the plans below for a better chance of winning!

    Join the contest Subscribe

What is a headspace tester ?

CygnusX1

Sergeant of the Hide
Full Member
Minuteman
Dec 22, 2019
130
84
Quebec, Canada
In a bolt rifle, the bolt pushes the cartridge into the chamber and keeps it there tight. There is no room between the bolt and cartridge so I don't understand what is being measured

The name implies it can measure the space but if there was a space, it would be dangerous to fire this rifle
Unless this thing measures spacing in the order of 0.001 inch
 

Attachments

  • IMG_2515.GIF
    IMG_2515.GIF
    680.2 KB · Views: 54
But there is.

When you fire a round, the brass will expand to fit the chamber, but then will shrink a bit, but will still be larger than before it was fired.

During the sizing process, you are bumping the shoulder back about .001-.002 inches.

So yes, the brass is smaller than your chamber by more than .001" and is still safe to fire.
 
There is a space, case should not be “tight”.

Secondly, you could call it a head distance gauge. It measures the distance from boltface to shoulder or to front of belt on belted cases.
 
Last edited:
Agree but I was trying to explain it in another term so that the OP would understand due to his apparent issue with the term headspace. The gauge actually measures distance from bolt face to shoulder, excess "space" is determined by the case size.
I got ya. I was brave to attempt to understand what was going on before my coffee :ROFLMAO:
 
  • Like
Reactions: RTH1800
But there is.

When you fire a round, the brass will expand to fit the chamber, but then will shrink a bit, but will still be larger than before it was fired.

During the sizing process, you are bumping the shoulder back about .001-.002 inches.

So yes, the brass is smaller than your chamber by more than .001" and is still safe to fire.
I'll be dammed...
I did not know the brass would expand.....
I just saw it tight and the bullet forced to go out :)
But it makes sense that the brass needs room to expand otherwise it would jam in the chamber.

I am not used to thinking in terms of 0.001 inch as "loose"

Thanks for your help guys !
I appreciate it (y)
 
If the headspace gauge is that precice and "reads" thousands of and inch precision, then the chamber actually softened and changes size over time ?

Hard question: How much change does it take to have high pressure gas blow into the shooter's face ??

Fact: I own a WW1 0.303 Ross rifle and it shoots but I think I will buy a gauge just to see if it's borderline worn out
 
A headspace gauge is a solid chunk ground to represent the minimum headspace and is called Go-gauge.
Chambers can stretch and lugs can compress with age.
There are specifications for a NO-GO and FIELD gauge to check for this.
If a gun started out close to the Go specification then changed over time the Field spec would indicate it's worn out. Maybe in the 0.010 to 0.012" range.

There are chamber measuring devices that you set and read with a micrometer or caliber.
These allow one to set reloads to a desired "less than chamber" length based on cases fired in that exact chamber.
That might be 0.001" for benchrest to 0.003 for a semiauto.
Really tight chambers may or may not close on all commercial ammo which might have a range of 0.003, usually short but not always.

The two primary uses are checking for excessive/unsafe headspace, or setting reloaded cases to a desired shorterness to minimize stretch when fired. Repeated stretching, bumping back to size when reloading, stretching the next time, over and over wears out brass and cause failure.
 
  • Like
Reactions: CygnusX1