Re: powder for 308 auto (Win 100)
If you've got adequate neck tension you won't need to crimp, even for semi-autos. Might be worth trying the Lee FC die, simply because it's a variable. The recommendation to take a look at SB dies is worthwhile, too. They standard FL dies may do just fine, but you'll always want to FL size for an auto, and if there's an issue at that point, then try the SB dies.
Just remember that reloading for semi-autos is substantially more complicated than loading for a bolt gun, and you really do need to approach it diffrently. You need to consider and check things that would never have a bearing in reloading bolt guns, and that's just the nature of the beast. If you're not already using one, I'd also strongly suggest that you get yourself a headspace gage like the Wilson chamber type or something like an RCBS Precision Mic, and use it when setting your dies up to load for this rifle. You want ot allow for a shoulder bump of .003"-.005" with autos, not the .001" you'd use with bolt guns. Check your primers and make sure they're seated below flush in the case head, to ensure there's no slamfire issues. You get the idea.