They are one and the same. A-Square just worked the SAAMI effort for the standard 338-06 to "legitimize" the round. The drawings in the Speer #12 and A-Square manuals shows all to be the same save for a 30 minute difference in shoulder angle which is meaningless with proper headspace. I have been shooting one for years and use Winchester 30-06 brass and a 338 expander plug and do not bump the shoulder. I have also fired the factory Weatherby 338-06 A-Square load with no issue. Cliff LaBounty did the rebore/chamber on mine long ago. Used it just a week ago to take a nice bull elk.
