CIP Headspace Gauges ?
- Thread starter waltk
- Start date
Walt Krafft
Gold $$ Contributor
Headspace tolerance is cartridge specific. There is no standard.
waltk
Gold $$ Contributor
Really?
WSnyder
Silver $$ Contributor
In general a lot of (maybe most?) SAAMI chambers from min to max shoulder datum is .010" difference but not all. As he said you need to look at the particular SAAMI cartridge to see what min max is. Are you confusing the various go, no go, field gauges and their dimensions?
dellet
Gold $$ Contributor
CIP and SAAMI chambers for the same cartridge are not always the same. I know of one person who sent a rifle to Europe and it could not pass Proof testing for this reason without a lot of extra time and expense.
If you look at CIP spec prints they do not have a “headspace” measurement. The distances from base to body to shoulder junction and base to shoulder to neck are defined along with the angle. No base to shoulder datum measurement. CIP, like SAMMI has a minimum chamber with both length and diameter maximum allowable variation.
What is interesting is that those lengths are basically the same, but in a SAAMI chamber +.002” length allowance somehow translates into .010” headspace variation. More than combining diameter and length would seem to cause.
If you look at reamer prints you can find 30.06 Springfield in both SAAMI and CIP versions and they differ in measurements, more than converting inches to millimeters. Also worth noting that the CIP reamer print does include a reference or datum line on the shoulder with a tighter tolerance and that point is at a different diameter on the shoulder than the SAAMI reamer.
Good for Forster for filling a gap.
If you look at CIP spec prints they do not have a “headspace” measurement. The distances from base to body to shoulder junction and base to shoulder to neck are defined along with the angle. No base to shoulder datum measurement. CIP, like SAMMI has a minimum chamber with both length and diameter maximum allowable variation.
What is interesting is that those lengths are basically the same, but in a SAAMI chamber +.002” length allowance somehow translates into .010” headspace variation. More than combining diameter and length would seem to cause.
If you look at reamer prints you can find 30.06 Springfield in both SAAMI and CIP versions and they differ in measurements, more than converting inches to millimeters. Also worth noting that the CIP reamer print does include a reference or datum line on the shoulder with a tighter tolerance and that point is at a different diameter on the shoulder than the SAAMI reamer.
Good for Forster for filling a gap.
jareese
Gold $$ Contributor
When none of them can agree on a standard for WHERE the actual Datum line is, that makes things a little more less standard. I've seen a few seperate HS gauges for the same cartridge, from same manufacturer, vary by 4-6 thou... I don't buy cheap the ones.
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