No, but I assume you've measured your bore to make sure they are safe and also, that you can measure a safe OAL distance so that the oversize bullet does not jam in the lands, (it is not the SAAMI/CIL OAL length distance for .264" bullets and you will have to determine it yourself). If you do all that, they should give you much better velocity if your bore is (in today's terms), "oversize". The cartridge will look a bit odd because the bullet is so much deeper in the case.

Do Hornady still make it? Perhaps contact the Hornady importer direct. Hornady in the US are very helpful, if you need to contact the factory direct to confirm anything.