Checking headspace

[kyrol60]

I own A M-14 and was wondering if there is any other way to check headspace accurately, I already read about "GO" and "NOGO" gauges, but that only tells you that your headspace is between 1.630 and 1.634, but I want to know when my rifling starts. I remember reading somewhere about taking a mold of the chamber with some king of special liquid that does not shrink when harden and gives accurate molds of your chamber. Does anybody know what I am talking about. Also is there any gunsmiths in southern Alberta that can work on M-14. Your info would be a great help.


Kyrol

 

[guntech]

Headspace has nothing to do with where your rifling starts...

where your rifling starts would be easiest to establish if you were reloading the ammunition and had empty sized cases and bullets and a little time...

 

[sunray]

"...special liquid..." It's called cerrosafe. Brownell's sells it.
Headspace guages only tell you if your rifle is within spec. They don't measure anything. If the bolt closes on a Go but not on a No-Go you're fine. Where the rifling starts doesn't matter except for establishing max OAL for hand loads. If you're not reloading and are using milsurp ammo, knowing where the rifling starts won't matter either.

 

[tiriaq]

If you want to find out the maximum length of a loaded cartridge when the bullet is touching the leade of the rifling, you could try this: Take an empty sized case. Carefully slit the neck lengthwise. Start a bullet into the unloaded case. Gently push the test cartridge fully into the chamber. The bullet will contact the rifling, and will be pushed back into the case. Gently remove the test cartridge from the barrel and measure over all length. You might want to repeat. NEVER load a cartridge for a semi-auto that allows the bullet to touch the rifling. If you unload, the bullet may be jammed into the rifling, and left behind. Load another round, and you could have two bullets. Generally in a rifle like yours, oal is determined by what will go into the magazine.

 

[Greenman1867]

You can also fire a primer only, remove the propellant and projectile, fire the primer and you can then measure the primer set back.