I wouldn't worry about it, Hodgdon lists 4.0gr as a max load but just using a magnum primer shouldn't increase your pressure much, if any.
If you're worried about it drop down a .5 gr as mentioned above, and work your way up to preference. As long as your gun will fire the magnum primers they should work just fine for you.
"There is no hunting like the hunting of man, and those who have hunted armed men long enough and liked it, never care for anything else thereafter." - Hemingway
The greatest ignorance is to reject something you know nothing about.