The load that seems to shoot really well in all of my rifles is:
Rem brass
federal 210 primer
Hornady 170 gr interlock Roundnose
50.0 gr IMR 4064

Work up to this load as its close to the maximum loading already. You might find that the RN bullet will not feed very good- it feeds flawlessly in 7 of my rifles, but is not reliable in the other 3. Make sure you can load the entire magazine and still be able to feed without jamming. If it jams, Take the extractor off, and polich the underside of the claw(the side that faces the bolt face) this will often times fix feeding problems, if not, the Feed ramp and one or both of the receiver rails needs polishing or slight modification, but have a gunsmith do it- its too easy to ruin your receiver.

8mm brass- its probably not worth your time to mess with trying to make 8mm brass from something else if you can buy it for Around $25 per 100 from Grafs, or or other suppliers- if you go to a gunshow, you often find brass vendors that will sell it for this price for new brrass and you won' t need to pay shipping charges.