Sooo if you want to be cool and poke the holes in the paper go with “gimmicky” and “popular” 6.5 CM.
However, If you want the knock down power, penetration coupled with the ammo availability when the times are rough go with proven 308.
Remember this; the 308 will do everything the 6.5cm does, only with just a little bit more work. Don’t be lazy and learn how to operate your gear and you will be fine with the 308.
If ammo availability is not important, be my gust and use a wildcat caliber.
I'm a new guy around here, so take it for what it's worth. Just saying "beyond 200 yrds" is kind of wide open. What do you think is your maximum distance? For me, walking to a paper target I've been shooting at 500 yards, could take awhile. Gun, and especially barrel manufacturing has come a long way, lots of guns are very accurate that you can buy over the counter. But they may not be precision 1000+ yrd guns. Lots of reasonably priced package guns available that will shoot out a few hundred yards in .308 but unless you are invested in .308 you might consider 6.5 creedmore. I read up on the drop of factory rounds, within your selected distance limit, and see what you can live with. Enjoy in good health.
Hornady 225 ELD Match
Sako TRG 22 (26 inch barrel)
Schmidt Bender PMII 10X42
Having three good reasons why you would prefer .308 over 6.5 Creedmoor is worth pondering prior to purchase.
"It's a long way to your 1000 yard zero."
My recipe for 175SMK stayed supersonic just a hair above 1K. I've read about guys loading their 308Win's with 200+grain bullets and extending the supersonic range. Admittedly, I haven't experimented with extra heavy bullets for the 308 because I swopped LD focus over to the 6.5CM. My Mil holds for 1K were 10.5 mil for my 175 SMK 308 load and 8.4 mils for my 6.5CM pushing a 140 Berger Hybrid Target.
It appears that new life is being pumped into the old reliable 308 with these heavy bullets. I personally like to shoot my 308 with 175's. I have 3 precision 6.5CM's and 2 precision 308's. My gut tells me all things being equal, if you are pushing a 200+gr bullet, you are going to have more recoil even with a brake or a can on the end of your barrel. I don't expect this to be a big difference but if you are shooting PRS style shoots there might be a slight recoil difference. If you look at what the Pros are using in PRS style shoots very few are shooting 308Win. Check out what serious competitors use in a December 2018 article in the Precision Rifle Blog.
Don't get me wrong I like the 308 but technology in cartridge design has progressed since the 308 was introduced in the 1950's. 308's still a great overall round but things like subtle changes in case shoulder angles have been found to increase the efficiency of a round. I believe that if you dig into the specs, you'll find the 6.5CM to edge out the 308 in some key categories. While the 308 ammo is fairly available, 6.5CM is showing up on more and more retailers shelves. Just my .02
Love the 308 and love the 30.06. Both can do a great job at 1,000 yards and out.
So basically nothing custom , just something I can go and buy.