I would go with the neck size for reloading the .223. It is easier on the brass. If you have trouble with sticking I would polish the chamber.
H&R/NEF use their tooling a bit beyond what most manufacturers do to help keep down the costs. As a chamber reamer wears out it might leave scratches what will grab the brass and hold on to it. Polishing will usually solve this problem.
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Check your chamber real carefully for scratches,
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and polish them out if you find any.