1972RedNeck,
Magnum primers make a larger volume of gas than standard primers. This is to provide adequate start pressure in the larger volume cases that magnum cartridges have. This is especially important with spherical propellants, whose burn rate is controlled by deterrents that have a high concentration at the grain surface and then diminish exponentially so the burn into the grain makes gas progressively faster as the grain burns down, despite the surface area of the grain shrinking as it burns. It is quite a feat, but it means the surface concentration of deterrents in the grains has to be high, making them harder to ignite. This situation is improved by the magnum primer's higher start pressure, and the aluminum in most magnum primers makes hot sparks that can burn through the outer deterrent layers.
Stick powders are not as hard to light, so magnum primers have less benefit with them. Also, whether you use magnum or standard primers, either powder type will still ignite and go boom. The issue is that with a bigger space to pressurize, the harder-to-ignite powders may not pressurize and burn as consistently without magnum primers. This results in bigger velocity SD and larger groups, especially at longer ranges. Note that folks using larger medium power cartridges, like 30-06, can also see a benefit to using magnum primers when their load density is low. This is because the empty space in a low load density cartridge needs more gas to pressurize, too. A lot of folks shooting "Garand loads" in 30-06 have found better consistency and accuracy with magnum primers because a lot of those loads only achieve about 80% loading density, leaving a lot of empty space in addition to the space between the grains that is already there.
So, go ahead and run the standard primers. I had a situation once with poor ignition of a poor case-fill load of a spherical powder in .308 when I used standard primers, but it was significantly improved either when I used magnum primers or when I deburred the flash holes in the cases. Your 4350 shouldn't be as difficult as a spherical powder without a magnum primer, but if your cases have burrs, I would go ahead and deburr them so you have the maximum uninterfered-with ignition spark from the standard primer.