FatBoy,
I've been using a 6.5x57 for about 8 months now, It 'was' a factory zastava before someone else robbed the action, so I grabbed the barrel, loading dies and some loaded rounds and rebuilt it on a 98 action.

Shoots like a dream with hand loads, mind you I've never bothered to even look for factory stuff here in Australia.

I have the original set of dies that I acquired with the barrel, which I think were 'Falcon'? if memory serves me right. But i have since acquired a Redding 3 die set which work well with certain brands of brass but not with others.
I generally resize 8mm mauser brass down into 6.5mm but I have used 7mm mauser RWS brass and necked it up to .30 cal then necked it back down to 6.5 to give it the false shoulder which also works well (I think i found that idea in a cartridges of the world book?)

You might find that you will need to try a few brands of brass to get things working right though. I found that using Remington 8mm mauser brass necked down 6.5 in the Redding dies the projectiles are only held loosely and you can pull them out with ease by hand.
I don't know if this is a function of RWS having thicker case necks than Remington and the Redding dies allow for that? but I found I didn't have any trouble using Winchester 8mm mauser brass or the 7mm RWS brass. I'll be trying Federal brass next to see how that goes, as I'm lead to believe that has quite a thick neck too.