The 6.5x54 M-S and 6.5x53R in Steyr and M-S rifles usually make fine rifles. But the often heavier for calibre bullets at 160 grs and round nose shape often limit the cartridge, especially at longer ranges. And also if in some rifles good feeding from the magazines require it.

The 6.5x55 on the other hand works wonderfully with 140 gr spitzers. Also 120 gr or heavier bullets. At velocities allowing longer ranges.

I find these super expensive 6.5 Creedmoor "sniper" rifles funny. $6000, $8000 for a very ugly plastic and aluminium precision rifle. But alleged to have wonderful accuracy.

My M38 1896 military actioned 6.5x55, even when in its cut back wooden military stock, using "military"/target ball ammo, approx 140 grs shot tiny one hole groups. It's now has a cheap black plastic sporting stock. And shoots pretty much the same. One day I need to get the military two stage trigger replaced as it is way too heavy. Imah0gine the groups with a finecset trigger?

Oops cost me $100 ... maybe $180 ... plus the cheap plastic stock.