Need Help with Hornady Full Length Die

[Thelaststraw]

Factory ammo uses base sized brass at minimum SAAMI spec while the Hornady die will not size it down to minimum spec, so the diameter of your sized brass is likely not the problem.

Are you confirming that you're bumping the shoulder down with a comparator?

  The shoulder was where I had problems with specifically. I didn't anneal my brass and some wouldn't go into battery fully when magazine fed. Slamming them home from a locked bolt would do it. After 1x fired they were good to go. 

Interesting about the Hornady dies though. I thought they did size to saami min. Learn something new every day (especially me when it comes to rifle cartridges....lol)