How can I tell if my M1 carbine (or any other rifle) has wrong headspacing?

[Oleg Volk]

Would simply lack of problems such as bulged brass do it or ..?

[Southla1]

If you do not own a set of go/no-go headspace guages for the particular caliber you want to check the best thing you can do is take the weapon to your neighborhood gunsmith and have him check it.

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Carlyle

[Oleg Volk]

I am curious what kind of problems excessive headspace would cause: blown-out brass or something else?

[Master Blaster]

Having mostly owned .22 rifles and one .30-.30 winchester I dont really understand what is meant by headspace could someone please explain why it is important.

Thanks

[Noban]

VERY simply, head space is the measurement of the space between the bolt face and where your cartridge seats in the forward chamber. It is important that the space be neither too long or short, as it could result in catastrophic case failures from expanding brass (and steel) cases.

Head space is measured in thousandths of an inch. The gauges used to measure it are called "Go", "No-GO", and "Field". A Field gauge is, if I'm not mistaken, more appropriately used in military applications and indicates a potentially very dangerous condition.

Generally, if you can't close your bolt on a Go guage (too short chamber), or can easily close it on a No-Go or Field guage (too long chamber), you better have the problem addressed by a competent smith.

BTW: I have a Mosin Model 44 that splits every shell fired in it, but gauges out fine. Go figure??!!

[alan]

Oleg:

Overly long headspace can cause a dangerous situation, Case failure during firing, allowing high pressure gas to get into parts of the rifle not designed to withstand high pressures. Possible injury to the rifle, the shooter and or others nearby. Slightly long headspace can cause short case life, not a problem for the military, who don't reload, but bothersome for civilians who might. Headspace to short, the rifle might not chamber a round, not dangerous, usually.

Master blaster:

See above. Headspace with rimmed cartridges, including the 30-30 is measured from bolt fact to "downstream" side of case rim. Overly long headspace could cause case failures, potentially a dangerous situation.

With bottleneck cartridges, for example, the 30-06, headspace measured from bolt fact, action closed, to a "datum line" on the cartridge case, see cartridge case drawings.

Same comments as above apply.

Hope this helps.

[bergie]

Oleg,
signs of headspace problems may include a slightly brighter or shiny ring around the case rather than an obvious bulge, or loose primers as the most obvious. Having a smith check it, esp. on any older mil.surp. firearm is highly recommended.

Master Blaster,
Headspace to say it as simple as I can, is the amount of space in the chamber (from the breechface forward)for the cartridge to fit, usually only about .005". This space is necessary because if the cartridge was exactly the same size as the chamber, it would cause extremely difficult extraction of the fired case, and any irregularities in the ammo would not allow it to chamber. It is measured in different ways for different cartridges, (straight, bottlenecked, rimmed, rebated, belted, etc.) but always from the breechface to one of the following: the front of the rim, the datum line (a design reference) on the shoulder, the case mouth, etc., as the design of the cartridge calls for. Excess headspace can cause problems from stretching and weakening the case, sometimes causing blown primers, or case head seperation, and can be dangerous as hot gasses may come back toward the shooter.

hope this helps
Bergie

edit-add
wow, a couple of good answers real quick while I was trying to post and yell at the kids at the same time


[This message has been edited by bergie (edited March 24, 2000).]

[This message has been edited by bergie (edited March 24, 2000).]

[alan]

Noban:

The headspace in your Russian rifle could be O.K., however the rest of the chamber could be "bad". Also, your splitting problem could be caused by cartridge case problems. Improperly drawn brass, bad aneal, "age" problems. Like you mentioned, go figure.

[dZ]

i thought headspace was controlled by the capstan in your 8 track...
;)
just the faq... http://www.fulton-armory.com/headspace.htm