No difference, as others have said, in the mechanics of the reloading. Pretty simple there. You'll have to ascertain what sort of rifle you want I suppose. You said you already have it picked out, yes. But anyway, many rifles can be swapped out to accept both. The way I look at it, .308 is a fine place to start. It's easy to find brass, bullets, and powders, and primers will be hit or miss regardless of whether its .308/6.5. For example, I'm looking at what we have in-stock today and I grabbed a box of Barnes Match Burners for example. They are only $35/100. 6.5 die sets I've got for $50-60. For .308, I have Hornady 150-Grain FMJ BT's about the same price, and dies the same. Price-wise, I think you'll be in the same boat either path you go down. Reloading is fun, and a hobby too. You'll not save too much money, you'll maybe shoot more for what you were spending previously, or shoot the same, spend more, but ultimately have more fun doing it. I know you're not likely to go buy both rifles. 6.5 is the new hotness indeed, and it's certainly better out to a good range, better so than .308 after some distance. In the end, you'll have both rifles, so which do you want first? .308 is sort of a round to cut teeth on, I'd say. It's where I started.