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.
Those company types will often stick to the script and only talk about loads they've tested. To say that RL-33 is "playing with fire" in rounds other than what they have data for sounds more like something you'd hear from one of those behind the counter gunshop Ninjas who seem to know everything.
Serious .264 WM LR shooters have done some great stuff with RL-33, some saying it's the best powder for that round, period.
Check post here on the Fire for data and performance reports.
DF
