Depends - Is the rifle a "standard" chamber, or is it a custom rifle? If I recall correctly, some of the Sakos have slightly larger body diameters... 6PPC-USA?
If it's a custom, you may _need_ neck-turned brass. The barrel will often have the required neck diameter engraved or stamped on it. My 6PPC rifles are all .262 neck chambers.
At any rate, give Ron Hoehn a call at 1-636-745-8144.
He wants around $60 or so (not sure) per hundred pieces of WEIGHT SORTED Lapua .220 Russian brass (it's really beautiful stuff). You'll have to expand it and fireform it, but it lasts a good long time. I'm not sure if he sells non-sorted boxes, but he might. He also sells turned and prepped brass - All you've gotta do is prime it, charge it, seat a bullet, and yank the trigger.
Tell him Bogie sent you... He makes some very nice rifles too...
Just an addition - the .220 Russian is the parent case of the 6PPC, and most benchresters greatly prefer the Lapua brass, even though they need to go through extra steps in case prep, since folks seem to think that it is stronger, lasts longer, etc...