Is there any need to resize new brass. If so please explaine.

Some will say yes....some will say no. I just run it over the expander on my die to even up the case mouth and then to an inside chamfer and I'm good to go. I think the brass we get is pretty much what the factory uses although our case mouths are beat up.....I don't think they take the extra step of Full resizing before they load and some factory ammo shoots darn good.

What kraky said.

I run new brass all the way though full length resizing dies.

Does the body of the case need resizing? No, and in most cases you don’t even need to lube them.

The neck needs to be trued up. I hear about people that only run new brass in the dies far enough to open the mouth of a dented case over the expansion ball. A lot of people spend more time stopping the upward motion of the ram than just driving that darn thing through a full cycle.

I couldn’t care less about how other people prep their brass, what they do or don’t do, I only know what I do and it goes much farther than the question you asked.

I Partial Full Length Reasize all my new brass, just like I do all my fired brass. I've seen too many dinged case mouths / necks from the factories to trust them.