I knew the PP was a little shorter, but when you actually measure, it's a more noticeable difference.
Kynoch - 3.04" feed fine
Czech - 3.02" feed fine
PPU - 2.95" don't feed at all

Will the M/S dies work in a 7x57 lee hand loader I have? Forgive my ignorance, reloading is something I've considered for the future and I bought the small "Lee Loader" small all-in-one box

Thanks for the input guys