Full length resize after each loading, if you are loading for several rifles. Then you need not worry about chamber fit. Also seat bullets to no longer than recommended OAL from reloading manuals. Neck sizing and seating bullets out to touch the lands are rifle specific, not the general rifle. You can buy "small base" sizing dies to take the cases down even further that a standard full length sizing die, but if you do not need them, then you will be working the brass even more. Generally you do not need these unless you are loading for a semi-auto. I have 3 223's. I keep my cases separate for each rifle and reload for that particular rifle. I also keep case lots. That is; I buy new cases and keep them together for their entire life for each rifle. I may have 200 rounds for this rifle, 300 for that one, and 200 for the third. I do not shoot all three and then mix them up a tumbler and then pull them out and reload. I keep them together and separate from the other "lots".