I hate to sound like a broken record but I believe everybody on this thread has tried to make it clear that you should try MORE POWDER. You stated that you're at a STARTING load and are asking about switching to mag primers? I'm afraid that you may want to study hand loading a bit more before you get much further. Mag primers have a bit hotter ignition characteristics for slower harder to ignite MAGNUM powders and will have little effect on velocity when used with a starting charge weight of medium/slow powders in a 270 Win. Again, try MORE powder and watch for pressure signs. You shouldn't have a bit of trouble exceeding your gal's velocity numbers. One more thing to think about is that factory munitions are loaded with proprietary blends of powders that we hand loaders DO NOT have access to and will rarely be able to duplicate their velocity.