Sammi spec tolerances
- Thread starter gixer1
- Start date
Hmmm...not on the ones I have! Maybe because I printed them out though....SAAMI.
It's on the SAAMI diagrams if you look.
Sinistral
Well-Known Member
That's because it's from the Hornady Handbook, not SAAMI.
On the actual SAAMI drawings each dimension has it range...I must admit I found them a bit confusing...unlike the standard drawing dimensioning conventions I am familiar with.
For instance on the drawing above posted by @Border case length at 2.233-.020 is that a minus sign or a hyphen?
Actually it is more obvious on that 257 Roberts one than on the .308W which is the first one I looked at...2.015-.020 does that dimension range read as between 2.015" - 2.020" or 1.995" - 2.015" ? Cryptic.
Alan
For instance on the drawing above posted by @Border case length at 2.233-.020 is that a minus sign or a hyphen?
Actually it is more obvious on that 257 Roberts one than on the .308W which is the first one I looked at...2.015-.020 does that dimension range read as between 2.015" - 2.020" or 1.995" - 2.015" ? Cryptic.
Alan
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Think it's from the Lee book, but still not SAAMI agreedThat's because it's from the Hornady Handbook, not SAAMI.
SAAMI specs below. Looking at Border's 257 Roberts example above, you can see the maximum dimensions followed by the tolerance.
On the SAAMI pages, the cartridge dimensions are given in the upper image for each cartridge, chamber dimensions below.
In the 257 Roberts L3 dimension below [case length] it is written as "2.233 - .020(56.72 - 0.51)". So the max case length is 2.233", the minimum is 2.213".
https://saami.wpengine.com/wp-conte...99.4-CFR-Approved-2015-12-14-Posting-Copy.pdf
On the SAAMI pages, the cartridge dimensions are given in the upper image for each cartridge, chamber dimensions below.
In the 257 Roberts L3 dimension below [case length] it is written as "2.233 - .020(56.72 - 0.51)". So the max case length is 2.233", the minimum is 2.213".
https://saami.wpengine.com/wp-conte...99.4-CFR-Approved-2015-12-14-Posting-Copy.pdf
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Lee precision actually ....(although an old one!) I printed some off of the net and they were the same...but from what I have found it’s +0/-0.007” on length and +0/-0.008 on diameter. Would that be correct?That's because it's from the Hornady Handbook, not SAAMI.
Ah! Thank you sir!
I was the same Alan! I’m pretty used to looking at engineering drawings but these don’t seem to have a consistent tolerance!
thanks for the help everyone!
Agree . The notation is odd.
Looking at the 257 Roberts example above, and with comparison to the CIP pages for the same caliber, 56.72mm is clearly case length maximum.
Ergo, the lesser number that follows the SAAMI label for that same dimension must indicate by how much the minimum case length can vary wrt the maximum. [Still looks daft]
Personally, I find the CIP pages easier to read. Also, rifles made for European markets will be made to CIP spec, so using those pages over the 2015 SAAMI pages is probably wise if your rifle is from a European maker.
Link to the CIP pages is below. The listings start with metric calibers. Use scroll bar at bottom to move forward to imperial calibers.
CIP - Homologation
Link to the CIP pages is below. The listings start with metric calibers. Use scroll bar at bottom to move forward to imperial calibers.
CIP - Homologation
In your typed out example above you have added a space in between the digits and the minus sign which is not there on the drawing. The lack of spaces is one of the reasons why it could be misread as a hyphen and thus indicate "range between".
Part of the confusion lies in the lack of consistency within each drawing.
Sometimes they include a zero in front of the decimal point and other times not...even on adjacent dimensions!
I did sort it out by reading the other dimensions, and like you confirmed it with CIP but it did seem to be that the SAAMI editors had been a bit casual about it all...apart from anything else they had enough space to put in full both the min and max dimensions which would have been much clearer.
Alan
Sinistral
Well-Known Member
These questions are doing my head in, but now I see what they were leading up to.
I don't know the answer but logic would suggest they're made to seater die dimensions for clearance.
You whack the article enclosed with a mallet to size the neck.
Does the precision that the Loader body is made to matter?
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