Is it possible

I buy a lot of ground weed but I was thinking about grinding it very very fine to Keif like. If I grind my pre-ground in a coffee grinder into Keif can I use that and press it with my rosin press? And does anybody know what I would get back if I did that? Or what I just screw it all up?

No need to grind it, just rehydrate it a little and press it. If you grind it it's going to expand uncontrollable unless you got the rosin bags for it.