I hear little snippets of this being a good powder for 223. Local store has a bunch of it for cheap. Anyone with experience with it?
I use it in the 6.5 Grendel and have several loads to shoot whenever the weather clears up some.
I think that it would do a good job with the heavier bullets in the 556.
It's an excellent powder for heavy bullets in the 223, just be aware that it produces more gas and cycles the action harder if you're using a gas gun (AR15 or other semi-auto).
For light varmint bullets below about 55gr though, there are better choices. In my load workups, I ran out of room to fit more Lever in the case before topping out on pressure and velocity; that included vibrating each case to settle the powder (and that technique is still effective with Lever, even though it's a ball powder). In my experience, for 40-50gr varmint bullets in the 223 Ramshot XTerminator is a much better choice that gives top velocity and excellent accuracy; it has served me well for varmint loads in bolt actions and ARs.