The following links may help answer your question regarding velocity.

http://www.nosler.com/nosler-load-data/65-grendel/

http://www.hornady.com/store/6.5-Grendel-123-gr-SST/

http://www.hodgdonreloading.com/data/rifle

In general roughly 2400 to 2600fps in a 24 inch barrel and roughly a 28 fps loss for each inch of barrel loss from that 24" benchmark.

Example Hornady indicates 2580 fps from a 24inch barrel. same load from a 16 inch barrel is yeilding 2350 FPS. 2580 - 2350 = 230 fps diff / 230/8in diff in barrel length = 28.75 FPS per inch of barrel.

Different barrels, bullets and powders may vary some yet this should get you in the ball park

Last edited by Hunterapp; 03/05/16.
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