"Headspace" doesn't - or at least shouldn't - matter to a handloader. Don't set the shoulders back too far and the primers will get hit properly. If we can't do that then resort to neck sizing, that works fine for moderate pressure cartridges like the .30-30 and .35 Rem.
I doubt anyone could prove that Federal primers are any 'softer' than others but Fed does use a more sensitive priming pellet than others.
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