Measured Headspace - Now What?

[gravityfan]

British Military head space
If you reload and fire form your cases using the rubber o-ring method of an o-ring slipped around the rim of the case the word head space becomes meaningless.

As An example I lapped a zero bolt head to a head space of .084 and fired factory loaded Prvi Partizan ammunition without any ill effects using the rubber o-ring to control headspace. Actually it is zero headspace even at .084 because the o-ring is holding the case against the bolt face.

I am intrigued. I have been reloading .303 for a while, but I've not heard of this O-ring thing. Please tell me/us more; size, type, source, etc. Or would anyone like me to make a separate thread of this?

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[Parashooter]

I am intrigued. I have been reloading .303 for a while, but I've not heard of this O-ring thing. Please tell me/us more; size, type, source, etc.

If you handload for a .303 with generous headspace, there's often no need to mess with bolt heads - changing the rifle's clearances to yield longer case life. You can control cartridge end-play simply by changing technique.

When you fire a new case for the first time, use an improvised spacer ahead of the rim - anything from a precision metal washer to dental floss can work to hold the the cartridge head firmly against the bolt face and eliminate or reduce stretch even if end-play without the spacer would be significant. Another way of accomplishing the same end is to use a bullet seated out far enough to jam into the lands, "headspacing" on the bullet instead of the case. Such techniques are useful only if the rifle has excess headspace (or cartridges have abnormally thin rims). With normal headspace and cartridges, initial stretch isn't enough to worry much about.


O-rings are a slightly more costly spacer material preferred by some.

After you've fire-formed your new cases they will fill the chamber fully, stopping on the shoulder just like a rimless cartridge. If you neck size, you'll have zero "headspace". If you have to full length size, adjust the die so the cases chamber with just a bit of resistance in the last few degrees of bolt rotation. The result, if combined with reasonable-pressure loads, can be extended case life despite generous headspace.

[Edward Horton]

If you handload for a .303 with generous headspace, there's often no need to mess with bolt heads - changing the rifle's clearances to yield longer case life. You can control cartridge end-play simply by changing technique.

When you fire a new case for the first time, use an improvised spacer ahead of the rim - anything from a precision metal washer to dental floss can work to hold the the cartridge head firmly against the bolt face and eliminate or reduce stretch even if end-play without the spacer would be significant. Another way of accomplishing the same end is to use a bullet seated out far enough to jam into the lands, "headspacing" on the bullet instead of the case. Such techniques are useful only if the rifle has excess headspace (or cartridges have abnormally thin rims). With normal headspace and cartridges, initial stretch isn't enough to worry much about.


O-rings are a slightly more costly spacer material preferred by some.

After you've fire-formed your new cases they will fill the chamber fully, stopping on the shoulder just like a rimless cartridge. If you neck size, you'll have zero "headspace". If you have to full length size, adjust the die so the cases chamber with just a bit of resistance in the last few degrees of bolt rotation. The result, if combined with reasonable-pressure loads, can be extended case life despite generous headspace.

Parashooter

Your entire premise for your original “Headspace 101” was oiling and greasing your cartridge cases to keep the cases from stretching and thinning in the web area. When “someone” made your method “controversial” you edited your “Head space 101” to eliminate the words oil and grease.

The problem I have with your comments here is you admitted that you still oil your cases to fire form them, you read about the rubber o-rings like I did at Jouster and yet you are here writing about fishing line and dental floss as if you use it every day or at least after every meal.

Parashooter the o-ring method came from a Canadian at Jouster, the rubber o-ring centers the case in the chamber and fishing line and dental floss will not. I will say it again Parashooter you can’t have it both ways.

Oiling your cases doubles your bolt thrust and shortens the Enfield’s life expectancy by half and your “Headspace 101” told everyone to oil and grease their cases for over seven years.

Mr. Laidler told us during an Enfield FTR/overhaul an oiled proof round was fired and if the bolt was hard to open the action was scraped. This was because the surface hardness in the lug recesses had worn through.

It’s a little late for fishing line and dental floss and changing horses in midstream on a Enfield battered by excessive bolt thrust caused by oiled cases.