I've used quite a bit of Federal and Winchester brass for my 308 loads over the decades.

In general I've found the Federal to be a little thicker, and a bit softer. The primer pockets tend to enlarge rapidly and the brass can become useless after being loaded and fired a few times. I'm using near max level loads.

In general I've found the Winchester to be a little thinner, and harder. It tends to last a doggone long time.

Have built very accurate ammo with each type. I got a lot of Federal Gold Medal 308 brass for nothing, so continue to use it quite a bit. Just loaded some this morning. Once it's done, I just toss it.

If you wanted some real premium type brass, consider either Lapua, Norma, or Nosler. I've happily used those as well. Seems to be less brass-prep involved with those brands, but they are more expensive.

Regards, Guy