That depends on the brand of primers. With the Wolf primers "Magnums" are the recommended ones. With other brands....??? There is a lot of confusion and misinformation out there about the "dangers" of using magnum primers. Its not a simple subject as the manufactures themselves are not clear on what makes their primers "magnum". Now, Remington has a "small rifle" primer #6-1/2 that they tell you NOT to use in a .223 due to it being thin and not able to handle the pressure. They make a 7-1/2 primer that some books call "magnum" but that they recommend for .223. Go figure. Some say they only use magnum primers. Others say they use them in cold weather. One reference said, "Magnum primers may be helpful for ammunition that will be used in sub-zero weather conditions, but will rarely be necessary for general shooting needs." Note that they didn't say they should be used, they said they would rarely be necessary to ignite the powder.
I saw some good tests where a guy did all sorts of loads with different primers to compare magnums and regulars. Truth is, there was hardly, if any, differences in velocity between the two. Some will swear that magnums will cause excessive high pressure build up as they ignite the powder much faster. Is that true? Your guess is as good as any.
If you look at the amount of "fuel" in a primer compared to the amount of powder in a .223 there is a monumental difference in volume between the two. So, its hard to think that the primer can drastically change pressures. I have seen endless debate on this but have never seen any definitive proof one way or the other.
Do what some of us have done, just do a web search and read countless opinions on this. After reading twenty or so articles you will be more confused than you are now.
One point that many will make however is, if you start using ANY new component or load, start low and work your way up slowly from there.