6.5 Grendel II ~vs~ regular grendel.....?

[babaganoush]

... I really know nothing about the Grendel besides the little that is available on the internet. I do know a fair amount about barrels and chambers though.

GSP, its on the print as a reference, not a headspace callout. There is no throat on a SAAMI go/no-go gage. SAAMI isn't concerned with reloaders and to the best of my knowledge (which I may be incorrect and i apologize if that's the case), pretty much all the factory Grendel ammo fires fine in the AA and "GII" chambers.
Montana, the 264 LBC has a different throat dimension (LBC-.295" vs AA, GII- .300"). LB made a change to the dimensions themselves therefore changed the chamber as opposed to making it different.

Takes SAAMI spec ammo,
Takes SAAMI go gage,
Still not a Grendel?

I guess im just a bit confused about all the fuss over a different throat.

DDR

Forgive me if I appear to be restating what some consider the obvious:

Registration of a drawing with SAAMI is, by definition, the codification of all dimensions and annotations included on said drawing. Essentially, everything on that drawing is both specification and reference. Optional items are identified as such on many drawings that I've viewed.

A Go/NoGo gauge is simply a tool to determine only the headspace of said chamber. It cannot be the definition of the chamber in it's entirety, as it is blind to differences in neck size as well as other dimensions of the throat and chamber. This is clearly seen when using the 6.5 Grendel GNG gauges in a 264 LBC, which is an identified variant with a smaller neck.

As far as having a chat with one of members of the SAAMI committee goes, words over the phone or over a drink are really nothing more than opinion until and unless they are rendered official by a formal document. As I alluded above, if a document is registered with an organization (any organization), and in the absence of any formal declaration of exception by the organization, the entire contents of that document become official unless specifically exempted within the document itself.

ETA: Thanks, BjornF16, for providing other more drastic examples of the GNG gauge conundrum.