Headspacing "Go Gauge" Question...

[5hundo]

This might be a stupid question but I was just curious: Why can't you use a spent casing or a dummy round (or even a live round, under safe circumstances) as a "Go Gauge" for headspacing? Isn't that what the "go gauge" is checking for anyway? ...to make sure a round will chamber without having too little clearance?

[Plisk]

I don't think a spent round could work as an accurate "Go Gauge" because there are variables with what chambered it was fired in, and wheather or not that rifle's headspacing was perfect. I know know for sure, but I do know if you want accuracy, to just use standard headspace gauges.

[harmoniums]

You could pull a bullet, dump the powder, pop the primer and reseat that bullet.
That would be a cheap and safe and accurate go gauge

[eaglemike]

Ummmm, no. What chamber did the fired case come from? Was is low limit, or high limit? The brass also springs back some. If it was fired in a chamber at the low limit, there is a chance you could end up with an undersize chamber. Ammunition is supposed to always be somewhat smaller than the chamber. A manual operated bolt action rifle has some camming ability to force ammunition into the chamber.

I'd suggest finding a way to do the job right......

all the best,
Mike

[gunboat]

You can use a new case and shims as a "rough" check - You can not rely on the case to be at exact specifications - A fired case will reflect the size of the chamber it is fired in, so is not usable, but the fired case could be put into a case gauge which would also be a "rough" check -- -- A resized case can also be used as a "rough" check -- This presumes we are speaking of rimless cases -- A fired or new rimmed case and shims can be used for checking headspace on rimmed chambers -- just measure the exact thickness of the case rim and go from there - My ha-penny

[motorhead]

not fired. dummy or live with the gun rendered safe.

[WOLFPACK117]

I have used live round to headspace my FAL but, I was using an inch bolt (2pc firing pin)without the bottom just the head of the firing pin in the bolt.

[Redchevyman]

If you are re assembling an AK rifle and just wanting to make sure it's safe, just use a no go gauge. If the no go gauge won't fit than you do not have excessive head space. AK's are built with tight head spacing. A go gauge will not fit in most AK's. The actual ammo is smaller than the go gauge.

Once you establish that your head space is not excessive, take your rifle to a shooting range and load some live ammo into the chamber. If the bolt closes on the live round you are good to go.

[ar15barrels]

The maximum acceptable length for the shoulder on a loaded round should always be slightly less than the minimum chamber length of the gun.
If the ammo were longer than the chamber, it would not chamber properly.
So we can say with great certainty that go gauges are usually longer than cartridge cases in the shoulder length.

That's why you can't reliably use a cartridge case as a go gauge.