I've not done that comparison but based on other bullets of 300gr size and 777 2F tests I would estimate that your 85gr of 777 should be in the 1500 to 1550 fps range. The Goex load should be in the 1600 to 1700fps range +/-. In my testing in at least one rifle I've found minimal differences in velocity between same volumes of777 2F and Pyrodex P (3F) but I've not checked against Goex 3F. Barrel length will have some affect on these estimates, most of my guns have 26" barrels.