I've had mine up to 975fps with 93 grain nsa's. You will have to modify the internals of the gun to get there though. With that said, I have no doubt it can kill a deer. I would limit my shots to 50 yards and under on large deer though.
With that said, my personal opinion is go for a gun in 45 plus caliber with 400 or more fpe. The 357 impact, while being incredibly accurate when set up right, is a great yote and turkey gun. If you are insistent of a 35cal, then maybe the rattler.