He did not say why but I am assuming that because RL 33 was developed for large capacity cases and Alliant did not do any testing in the 264 mag. If you want to use it in your 264 mag please do so and if it works well you might want to tell them, as for me I own a very nice pre 64 m70 264 and I plan on keeping it in one piece, is it worth that extra hundred feet per second to take a chance and ruin a good rifle and maybe hurt yourself, I think not.
