TKS SharpsNitro - Donnely lists 6.5x300 WinMag as 93.24gr. cap. and the 6.5x300 WTBY as 96.21gr. water cap.
The 6.5 Crister Express, listed as .300 H&H. blown out with shorter neck and 43.6 degree shoulder is listed as 101.84gr.
I suspect ALL of these will produce just about identical velocities with the .26 Nosler.

The best aspect of the Nosler is that is does not have the useless belt. All belts do in rounds that do not need them, is to induce carelessness in hand loading, resulting in early case head separations. Relying on a belt to do your work will kill your brass almost as quickly as throwing it away.

The 6.5x68S (Schuler) has about identical capacity as would the 6.5/.308Norma have - right at of very close to 85gr.

The .264 Win. Mag. is listed as 81.51gr.