All that buffdog said.
also how accurate could it be with match grade hand loads ?
Have never played with a CG63 or 80 myself, but can report that most well tuned, well scoped, V.G.+ bored, match loaded M96 or M38
have held well under MOA for me. Those Tradeex M38 surplus barrels are tackdrivers. The three that I shoot hold 1/2 MOA.
This cartridge will perform decently with most any load one concocts, that said, it also will reward a well crafted match grade handload with consistently tight clusters.
A straight, no runout reload, with R22 under a 140gr Amax, seated to lightly jam (which is doable if your barrel is M38, ... not so, if a M96 long throat), has proved a good place to start. Work up to 2625fps or so, where you will most likely find an accurate node.
The long shanked .2645" 140 Amax is the easiest 6.5x55 match bullet to get dialed in that I know of. Some Swede's will gobble up the 139gr Scenar as well.
The easy way to beat runout is to use Lee collet and Forster/Redding BR seater dies.
Try a group with the noticably bent rounds, then one with dead nuts straight cartridges. Makes a difference, the more so the farther away your target.
Fast twist Swede's, loaded with long match bullets, often need some yardage to fully stabilize and "go to sleep". Not unusual, to see 100yd and 200yd groups that measure pretty much the same.