OP - hard to find a game bullet not good in 6.5, from 120 and up.
I have killed with my 6.5x55s, 260 with 120 Corelokts thru 130 AB.
The 55s really liked the 140s..that said, I have had a K1A Ruger shoot 1.1" at 200 yds with 130 NAB and wax a Buck at around 250-275. Most game IMHO is shot within distances that the BC diff is moot. Shot placement is always key. The 130 Berger is a bullet with a great record on game in the 47 Lapua. No reason why it and the 130 AB are discounted, BC's are plenty. I see the 120 BTs, 129/130s and 140s and others in between as all viable and highly capable on game to most sane ranges if accurate in your rifle.
To me, personally, shy of shooting very long distances, I feel the short action 6.5s are VERY well suited for 120-130s. I know this will get flack from many, who love BC/SD and heavy bullets. Trust me, I appreciate them too.
Drilled both shoulders of an 8pt buck at 100 yds with a 260 in a custom Borden Alpine...if anything the rifle was overkill for such a shot. At 200yd, it shot .5"....another rifle at that distance shot 1-1.25 consistently in putting the first 2 in the same hole, group after group. A Sako 75 GW. Also a 260. Also 130 NAB.
Use what works in your rifle, I don't chase speeds but in the 47 and CM one might have to push pressures hard to get speeds to one's expectations, with 140s. I see no need. I am happy with 130s - and for the record, my go to in 6.5 for game - is the Accubond, 130. Kills near and far, accurate....
Good hunting folks, many ways to reach ones endpoint. FWIW, MANY deer have dropped with 100 BTs and PTs from 260s and similar, even the Hornady 100 SP. I shot many thru a 6.5-308 before Rem did the Saami, and a buddy shot the 100 BT also in his 6.5BR in an MOA carbine...cloverleafs. Personally, these days I like to start with 120s in 6.5 as from there up you get a nice BC. I do have one exception when it comes to using sub 120s on deer/hogs. The Barnes 100 TTSX might be a helluva bullet for the small 6.5s, at most common ranges
Light? Sure. Fast? Sure. Mono - yep, won't blow apart on close shots, and should work fine to many common ranges, I would probably do test from 300-400 yds to determine expansion to know how far I want to shoot it.
Note, Long ago, MANY deer were shot at a GOOD Distance, including larger game ie. in Africa, using a 6.5 JDJ in a TC handgun, at around 2500 mv, bullet? 120 Speer and NBT.
Lastly, a friend used his 47 on an elk at just under 1,000 yds, dead elk, 127gr....
Ballistics are fun to debate, but when a bullet hits vitals, your endpoint is often the achieved if using a properly constructed bullet. Velocity and BC are nice, but one need not always have to max out either, to be very successful. Dropped a few deer from a 7BR rifle using 120s
My longest kill was a 6BR spitting 105s - at 400 yds. Many folks shoot rounds, with bullets and loads far more than capable.
Good Hunting, and Shooting folks, be safe (inc. handloading).