Re: 6.5 x 284 LA or SA
Unless you are OK with a single shot rifle, I would recommend a long action. I built mine on a long action and am very happy with it. Really, a 6.5-284 is a waste of potential in a short action.
If you just have to have a short action, .260 Remington, 6.5x47 Lapua, and 6.5 Creedmore are better options.