I am a rookie at reloading for the .223. Have both a Rem. Model Seven bolt and new AR15 (have not loaded for either yet). Purchased small base die set. Have new factory Win. brass on hand, as well as various factory ammo. Question, is all factory brass, as well as factory ammo, sized to "small base" specs? Further, exactly how does the sizing of 223 in regular dies differ from small base sizing?. When I see the specs in a load manual for case measurements, are those "regular sizing" or small base?

My main concern is whether or not I need to run all the factory brass through my small base dies before loading for the AR15. When I put mic on factory loads and new brass, were the same, but still not sure that really answers my question.

A second area of concern is whether I should also best get a "regular" or neck sizing die to load for the bolt, or just try out with the small base?

Thanks for your time,
DFM