An improper crimp can indeed damage neck tension by buckling brass a hair. I read cfullgraf's post to mean that.
A good crimp, especially a roll crimp, into a good cannelure with some depth for the neck to turn in to, can help the bullet from moving in rough conditions, such as banging around in the mag or bouncing off of feed ramps. The military does it for a reason.
I crimp 55 Gr FMJ ammo for blasting and plinking. I do not crimp any other ammo for .223.
A good crimp, especially a roll crimp, into a good cannelure with some depth for the neck to turn in to, can help the bullet from moving in rough conditions, such as banging around in the mag or bouncing off of feed ramps. The military does it for a reason.
I crimp 55 Gr FMJ ammo for blasting and plinking. I do not crimp any other ammo for .223.