Head space Gauges.

[Peter Laidler]

Looks like we're out on our own Sunray! I'm totally lost for words.....

[skiprat]

If I was putting guns I have worked on in the hands of others to shoot..(and I did for 32 years,, a few less than Peter!!!!).… I would always work to the accepted standards.....
And I would hope that work would last for at least 6 months. As stated in the EMER....
If only there were laid down standards.

If it's my own rifle and I'm the only one shooting it, I may be happy fixing it every time it will not chamber a round , or it fails for insufficient FFP.

[Bruce_in_Oz]

Headspace gauges of the most basic type, i.e., "GO" and "NO-GO" are ESSENTIAL to the OPTIMUM fitting of a barrel to a mechanism, regardless of the operating system of said mechanism.

The idea of the "GO" gauge is that a "standard" cartridge will enter the chamber without forcing.

On the other hand, if the mechanism closes on a "NO-GO" gauge, the headspace may be sufficiently excessive and allow all manner of interesting events; from failure to fire because of insufficient striker contact to primer backout / rupture which causes high pressure gas to "eat" the bolt face and striker tip. Another nasty consequence is case rupture caused by the brass having too much expansion room if it is ignited.

Proper gauges are precision ground and calibrated to a VERY expensive "check gauge". They are HARDENED tool steel so that they do not distort or wear rapidly in use.

They MUST NEVER be "slammed" into the chamber. Ideally, the bolt should be closed with finger pressure alone, preferably with any spring-loaded extractors and ejector REMOVED. Whilst "civilian gauges usually have full "extraction grooves", MOST modern "military" ones of my acquaintance have a fully rebated "tail" that clears extractors and ejectors and has a hole to clear the striker should it fall. These features greatly reduce the possibility of false readings and damage to the firearm in question and to the gauges, which are NOT supposed to be flung across the workshop by the ejector after use.

Beware helically-locked actions like Lee Enfields and M-17 / P14 types. Forcing a gauge into one of these is REALLY bad for the rifle and probably the gauge. The pressure of ONE finger until resistance is felt is all it takes. The firearm and gauge MUST be SPOTLESSLY clean before gauging.

I have quite a few headspace gauges in sundry calibres, rimmed and rimless, including one-thou. "incremental" sets for 223 Rem and .308 Win.

Know and understand your datum surfaces.

[Shovelrobert]

I have re barreled my 1891

What did you use for an action wrench?