Personal Rant here that I know will not be agreed with by most.
SAAMI Specs these get quoted in FB pages and other forums a lot. Often in the vane of they are something of a gold standard.
The SAAMI standards were and still are an American “thing” the Europeans have manufactured to meet these in some instances to enable selling into that market but have their own standards. Even then for the Americans it is not a Standard that “must” be adhered to they are purely a suggestion and SAAMI standards are voluntary. They are not like an Australian standard that may be applied to the construction of seat-belts.
I have had a look at a few of the cartridges (ones I have and have measured) both chamber and projectile drawings and they are just outdated. They were for when people were shooting much slower twist rates and much lighter projectiles.
Even some of the dimensions are just not being used these days for instance the neck dimension is one I have noticed. The more modern guns are using chambers much tighter than the SAAMI Spec would allow.
Then there are the tolerances again in some of the cartridges these are huge bigger than the min and max spec in some instances.
Rant over. They are a good idea but should be reviewed and updated.
Yes, they are really specs @sungazer. It’s a common denominator between ammo and firearms manufacturing. Alternatively, we could have a wildcat chambering per firearm manufacturer and possibly per model. Companies would love this, lock your firearm to specific ammo and specific case.
So yes, they are really standards that guarantee interoperability. Beyond that is up to you, you can make a cartridge in any way you want. However, you also need something that guarantees that factory ammo will chamber in your gun, that’s SAAMI.
While we’re rating.
Why the hell can’t reloading manuals just stick to one pressure rating system, don’t care weather it’s SAAMI or C.I.P., But I find it annoying when I’m going through the ADI manual and trying to decide on a load to work up and the bloody book goes backwards and forwards!
On to of those two ratings which I agree are a pain. As you look at some max pressures that are only 50,000 or less then see that they are CIP.
However in Europe they do have a true Standard where they have done a proof test on a sample to 125% of the max.
G’day sungazer,
SAAMI specs cannot be updated, they ARE the standard, and are a fixed point for that cartridge, like the British military Pattern, which was sealed and stored at Enfield Lock as the standard for that item. Any variation like those you mentioned regarding neck sizes are in fact outside the standard and do not comply with SAAMI specs regardless of who makes them or how many. We must have a fixed point against which all variations are measured. As for pressure ratings, don’t forget that the publisher of the manual does not do the testing, but simply prints other peoples data, some of which is US, some is Euro, and some is old LUP/CUP measures. All Proof tests are a true measure, just different types of mensuration and the reason is simple, Europe uses the ISO Metric system and the US still wades through the Imperial Inch system, so neither will change their pressure systems. Cheers.
Ill give you an example the 308 Win the head space is 1.630 - 1.640 the measurement tolerance is 0.015 thou 150% greater than the variance of the min max.
The 308 is also defined as having a barrel twist rate of 1-12. How many rifles are built with that twist rate today.
A standard that is not used is not a standard.
All standards can be updated again as easy example ISO 1902 it has been updated many times over the years with the variations indicated by the year after it.
Another example was back in 1990 the electrical Volt was changed along with resistance and capacitance. So physical standards are updated as measuring equipment is improved and the technique of defining them is improved.
So there is no reason why the specs of the various cartridges shouldn’t be updated as the world moves on.
I think the question was, whether it’s a standard. The answer is, yes. It is a standard. Can a standard be revised and updated, also yes. Sort of having two separate conversations here.
There are industry standards that industries agree to adhere to and saami are a good example. But they are not legally bound to. If it went pear shaped they might be sued, but not prosecuted.
Then there are standards that are legally binding, or expected. Move outside those standards and you can expect to be prosecuted if it goes pear shaped.
Australia safety standards such as the quality of manufacturing of fall arrest harnesses are an example for those.
The other thing is that it’s fairly normal that they are applied with a small amount variation at times.
Having said that ANSI is considered the US equivalent to our standards.
Was having a bit of a look around the web as I was interested in lead or throat angles for different shape projectiles as I thought they should be different for tangent and secant types. Rather than what was used way back when the bullets were made from stone. Turns out there are some barrel makers and gunsmiths that agree so check this next time you get a reamer built or a chamber cut.
Anyway as I was researching it was interesting to note that on the Berger site they said that only one of their bullet types was made to SAAMI specs. In multiple places they referred to the spec as outdated and restrictive.
“these SAAMI standards are in many cases outdated and can dramatically restrict the performance potential of a cartridge.”
My understanding of it is that given the shear range of cartridges available, both factory made and wildcats, how much can you adjust a chambering before it stops being that chambering? I was told not to use reloads that someone else has made or to at least be very careful when doing it in case they don’t suit my rifle, the reason being that when you can adjust seating depth for your rifle that doesn’t mean the next rifle in the same chambering has exactly the same amount of space in the chamber as yours which could lead to potential issues. Hence the need for the standard which you can then individually tailor to your specific needs.
Just my understanding
@Ats3 you have it correct. My beef was that they are not being updated as modern rifles progress. Or they could make a second version of them to take into account the new projectiles. It would be a bit of a nightmare you only have to look at the 5.56 Vs 223.
some quotes from Brian Litz
“As we’ll see later in this article, these SAAMI standards are in many cases outdated and can dramatically restrict the performance potential of a cartridge.”
“It is a fact that the ballistic performance of modern ammunition is directly limited by the SAAMI COAL standards that are currently in place”
“The first commercial rifle manufacturers who figure this out and start building rifles capable of feeding longer rounds will lead the way into modern times.”
I believe that you are mis-interpreting the dimensions that are the SAAMI standard for .308Win.
The headspace states 1.640"(41.66mm) max, and 1.630" (41.40mm) min. Those dimensions are absolutes in that they are stated as being max and min.
Certainly there are other dimensions which are permitted to have a tolerance; The clear statement is 'Unless otherwise noted all Dia + 0.002", Length 0.015"
W.R.T. the barrel twist, 12" refers to the test barrel from which data was measured. It is not a standard twist rate to which barrel makers must adhere.
Your reference to changes to some electrical parameters may only be to the extent of the way in which they are defined, but the properties of the Volt, Ampere, Ohm and Farad did not nor ever will change.
Sorry with regard to the Electrical standards some have not only changed in the way they are defined but in also the way they constructed. Some of them went from blah to being defined using Atomic particles and wavelengths.
With regard to firearm specs the main one that is changing from the spec is the chamber free bore spec to accommodate heavier and longer bullets.
