I've been shooting 6.5x55 for a good while. My Carl Gustafs M96 likes 142 SMK over a modest load of Re-22. Even with the original sights, it makes me look like a real marksman. The other is an old FN Mauser 98 that a past owner had restocked, installed a Timney trigger, and rechambered the original barrel to 8mm-06. It didn't shoot that well, so I installed a Brownell's 6.5x55 barrel ($86 at the time!). Recently confirmed that those are indeed a 1:9 twist. That rifle shoots traditional GameKing 130 and 140 inside an inch. Haven't tried the new GameChangers, but they're probably a bit too long. So here's the plan.
That old FN also does real good with Hornady Interlock 160s and (need to confirm at the range) Lapua Mega 155s. Where I hunt in my native state of PA, these have plenty of reach and a little more punch than the classic 300 Savage. So a new diet for the FN. Those GameKings will go to the Flaig's Mauser. Pretty sure they'll work. And, new barrel someday.
Remember, folks, I bought this rifle because it came from Flaig's. I'll work the caliber and have fun, but I would hesitate to recommend this or any other hot 6.5. The Creedmoor is a worthy successor the old Swede, but if you want a hot smallbore, my vote goes to the 257 Weatherby. And for a general hunter, I favor the 7mm bore.