I have been following this thread for a while, and would like to offer the following.
I have admired, from a distance, the 338-06 for many years, and have owned a Weatherby Ultralight for approx. 6 years, in that cartridge that Weatherby calls the 338-06 A-Square.
I am sure that there are drawings of wildcated cartridges that are called 338-06 that vary slightly in dimensions. You can find all kinds of things on the internet, and publications.
What I have found, and some here have confirmed, is that the 338-06 that we see the major die manufacturers selling and the 338-06 A-Square are the same dimensions. I reload with a die that is labeled 338-06 and it works perfectly. I shoot Weatherby factory cartridges and Nosler Custom, all with great results.
I think some of this dimensional differences some here are seeing are from the early days of this cartridges development. So I would suggest anyone with a older custom 338-06 check them for chamber dimensions.
As for Weatherby not chambering the 338-06 A-Square now, it is due to the fact that they could not sell them. Most people don't know what a 338-06 is, as can be seen on this forum by a group of gun nuts that still don't know the cartridge well.
When I purchase my Weatherby I asked my dealer why they seemed not to sell, and he said " few people who come into my shop have ever heard of it". What Weatherby did was chamber the round in it's lightweight but provided little to no promotion of it. I remember seeing one article written about the Weatherby 338-06. There was no advertisements, nothing! Contrast that to the .300 Winchester Short Mag. You could not pick up a magazine, or log on to an internet forum without a discussion or article, plus Winchester advertised it.
Weatherby says it failed due to poor sales, I say, and have told them that it failed because they (Weatherby) did not commit to it.
Someone noted also that it failed due to chamber dimensions. I am not sure that this contributed to the failure, but I do know that early rifles were recalled by weatherby to correct an acuracy issue, which I was told was an improper chamber. My rifle that I purchased had been recalled from my dealer and sent back to Weatherby for correction. My dealer, and myself believe that the added attention it got is why mine shoots so well. So there may be some Weatherby ultralights so chambered that still have a oversized chamber or some other issue with them.
Sorry for the long post!
