Noone has posted any 6.8 spc data with similar bullet weight/BC to prove otherwise, which is why i've been googling. Literally 2nd link is handloads of 120gr SST and it's right there with the grendel in the 2300s. Both at 12.5" of course. Which is why i proposed the question of reloads stretching the 6.8s legs, because to attain BC comparable for the 6.8 i gotta go 130-145gr.

Is that not what i linked to? Both what i could find quick googling 120gr range with somewhat comparable weight/BC to the 123gr 6.5 out of a 12.5" barrel length. 12.5" will be the length i go with regardless of caliber chosen. Don't want a javelin once the can is on. What realistically could you expect from say a 145gr ELD-X from that barrel length?

Think i could squeeze an extra 100fps or so out of the 130s in a 6.8 over 130s/129 in the grendel?

You can't use a 145eld-x, the bullet is too long. A Berger 130 Classic Hunter is about as long as you can use in a 6.8 and it still fit in the mag. 2450-2475 out of a 12.5" .

A Grendel will only push a 123gr to around 2550-2600max with hot handloads out of a 20" barrel, 200fps less with a 12.5" barrel 2350-2400 and notice that is using a bullet that is 7gr lighter. If you choose a 130 for the Grendel you will loose another 70fps.

A 6.8 130 Berger has apx the same BC as a 6.5 123gr ELD.

One other thing to consider, when bullets slow down to the point they will not expand that is really the max effective range. Big heavy 6.5s made for a 260 Rem or 6.5 x55 may not expand very well shot out of a slower Grendel.

BTW I'm not getting figures from google, I've been shooting both the G and 6.8 since 2005.