What resizing Die

[firewalkerd1]

I just made the jump into a black rifle in 223. My question is what die and why should I use for resizing, small base, FL or both SB-FL. New to AR reloading I load for bolt rifles and pistols.

[Gofaaast]

If buying new get the RCBS AR series and you will be set. They have the seating die that has the proper crip for that rifle integrated already and SB sizer. If you have dies already use those if you can crimp with them, or buy a Lee FCD. You don't want a bullet pushed into the case during fire, creating a high pressure situation. If you are starting with brass that has not been fired in a large chambered rifle (once fired military) in my experience and other friends, you won't need a SB sizer. Redding also makes fine dies for a little more money.