to crimp or not to crimp 223

[shooter38]

Just started reloading 223 some say crimp some say not to crimp what are your thoughts?

[papajohn]

For a bolt gun it's a good idea to insure proper shot-start pressure, but some guns shoot better without it.  In a semi-auto rifle it's necessary.  Nothing will tie up a clip-fed repeater like a bullet that collapses into the case and fails to feed. 

[gearheadpyro]

If you are shooting an auto loader it is pretty much required that you crimp. Bolt guns are a toss up, some shoot better crimped others don't.

I crimp all my rounds for my .308 using a Lee Factory Crimp Die. It has shrunk my already very good groups by nearly 20%. At only $10-$15 this die is certainly worth investigating.