What's the best way to measure headspace?

[Selmer]

I'm looking for the best way to measure headspace on my rifles so that I can adjust my dies to neck size and just bump the shoulder back a couple thousandths.  Any info you can shoot me would get great.  Thanks!
Selmer

[Leftoverdj]

You don't need to measure to do that. Just adjust and try until a stripped bolt will close on a sized case without resistance.

If you really want to measure your headspace, use a go-gauge and add shim stock to the head until you feel resistance on the  stripped bolt. Thickness of the shim stock would be your nominal headspace. For actual headspace, use a cartridge instear of the gauge.

[Selmer]

Just adjust and try until a stripped bolt will close on a sized case without resistance.

I'm not one that's scared to say when I don't know what someone is talking about, so, what are you talking about Leftoverdj?!?!
I can guess what you mean, but I don't want to do it wrong...
Selmer

[JBMauser]

The previous answer is correct.  I will come at it from another angle.  this is for rimless cartridges.  First - If you have a fired case from your rifle and you wish to neck size that case then headspace is irrevelant.  When you fired your case it was formed to the chamber and it shrinks back a bit to allow for extraction.  If you adjust your die to resize your neck only you will not have to bump your shoulder back at all.  If you do want to bump the shoulder many will paint the neck and shoulder with a Sharpie marker and adjust the die and check for ink scraped off the brass until the shoulder is just marked.  If you shoot light loads, over time the shoulder will move forward until you can't close the bolt and you will have to bump the shoulder.  

Now, you can measure your headspace with a proper gauge or some will remove the extractor and firing pin from their bolt (stripping it) and then chambering a loaded factory round.  Then place ever increasing layers of tape on the back ot the cartridge until the bolt does not close.  If you measure the thickness of the tape you have the "excess" you have in your chamber.  This is assuming the factory ammo is in SAMMI Spec.

All chambers should have some excess to be in spec.  The goal is not to have the round fly around in there but also not to be snug on closing.  

This is most crucial in mill surp rifles where specs may have suffered due to wear and hasty manufacturing.  

Hope this helps,  JB

[Duffy]

A Stoney point Head-n-Shoulders gauge is a hell of alot easier and will help you keep track of case headspace chages faster and very accurately.

[PaulS]

I'm looking for the best way to measure headspace on my rifles so that I can adjust my dies to neck size and just bump the shoulder back a couple thousandths.  Any info you can shoot me would get great.  Thanks!
Selmer

Selmer,
you don't need to measure your headspace to adjust your die. You don't need to "bump" your shoulder back unless you are shooting loads that are so hot that they are stretching your chamber beyond the elastic limits of your case.
If you are using ammunition that is developing pressures at or below the SAAMI maximum standards then all you need to do is one of the following:

1.
With your normal sizing die in the press and backed out so that it will not touch the fired case with the ram raised completely, screw the die down onto the case. when contact is made with the case mouth. From that point screw the die down about 2/3 the length of the neck. This will size enough of the neck to hold a bullet but leave a portion of the neck expanded to center in your chamber. The rest of the case is already expanded and fits the chamber well enough to center.

2.
with a neck-sizing die in the press and a fired case in the ram, raise it completely. Screw the die down until it just touches the case neck. Then screw in the die to 2/3 the length of the neck.

Both of these methods do exactly the same thing. As long as you do not exceed the SAAMI standard loads you will never have to "bump" the shoulder back. The brass will simply expand to fill the chamber and then relax back to the size it started at. You may after a large number of loadings have to anneal the case necks but I have found that I get more than enough loadings without ever doing the annealing process.

May you bullets fly true and your aim be perfect.
PaulS

[Dave in WV]

To accomplish what you want you can "smoke" the neck and top of shoulder area of a case fired in your chamber with a lit candle or match. Have your resizing die adjusted up so it can't contact the case shoulder. Gradually adjust the die down until you see it has just barely bumped the shoulder. You can tell by the smoke is wiped off of the case where resizing has taken place. I usually stop before the shoulder is set back any.Dave