I agree with oldpapps and Ifishsum and recommend that you reset your resizing die with the shell holder touching the die at the top of its stroke (with brass actually in the die). After resizing, I would then check the case length and if it is over 1.76", trim it back to 1.75". A case that is over 1.76" can and will cause a jam.
If you do both of those things and still have a stuck case issues, then your AR probably has a very tight chamber and you probably will have to go to a small base sizing die.
There are many threads on crimp vs no crimp. Personally, I would not crimp a .223 bullet unless it had a cannelure. If you need to crimp because of bullet setback issues, then you may have additional sizing die issues, further justifying the need for a small base sizing die.
Hope this helps...