Check Reloadersnest.com for load data. They have a good bit of info, but always start at least 10% low. If you want to pay 19 bucks ammoguide.com is also good for load info. As far as the caliber, it is the ony 6.5 I never intend to own. It is horribly inefficient and I can put a safe but high pressure load in my 6.5-284 and come very close to a 264 win mag with 15% less powder. Not trying to change your mind, just not fond fo the cartridge. However like others said, you need a 26 inch tube at a minimum, and if you are building it, I would recommend a 28 inch, even for a hunting rifle. My dad has a 280 ackley with a 27 inch shilen that has been turned down to an ultralite taper, it is bedded nicely and on a Husqvarna action and shoots sub MOA with anything I have tried in it, but I have limited reloading time with it, maybe 8-10 loads. Point is you can get a lot of potential from a long lightweight barrel. I'd go with a medium sporter type taper. You guys will notice I haven't ordered barrels for a custom rifle
so I don't know the numbers on the tapers. But I have played with a lot of custom rifles
others have had built.