I shoot a .300 WinMag. I also feed from the magazine, so I want the bullets to stay in place. I have gotten great results with the Redding Taper Crimp Die. Gives it a nice taper crimp, without mashing(technical term) the case mouth. No cannelure needed.
I don't crimp 'em too much, I adjust the die till it touches the case, plus about 3/4 turn.
The Lee Factory Crimp Die will give you as hard a crimp as you like, but it mashes the case mouth, making it thinner, and requiring trimming cases to length more often.
Many say a crimp is not conducive to best accuracy, I believe CONSISTENCY is the key. My results show very consistent velocities, and STELLAR accuracy.
By crimping, you ARE introducing another variable, so you have to pay attention. Any that don't "feel" right when crimping, I segregate, and use for foulers and coarse work, like whacking steel maidens, shooting offhand, etc.
To get a consistent crimp, your cases need to be trimmed to the same length. Hope this helps.