Alright so rails are wicked easy for me. i can do k-feds, brittanys, ray-feds and so on but on boxes, i can't get any edge pressure. The only way i can do swaps is if i do a 270 on. If i scissor my legs more it feels like the box digs into my ski. i don't know what to do
Try not to scissor your skis as much on boxes as you do on rails. Rails aren't as wide as boxes so you can use both of your skis to get leverage whereas on boxes you should think about keeping your rear foot flat and then dipping the tip or tail of the ski on your front foot to give you leverage on the box. Also, you can use your ski/edge for stopping/starting your momentum and setting up for tricks, but you still need use your upper body/hips to generate the spin necessary to spin, switch up, etc. Hope that helps!