any bracing involved when removing front rails?

unfortunately my camera is broke right now so i have no way to put pics up i got it a little closer after i bolted the kmember back up i tacked the front half of the rail in and i can pretty much get the rail almost touching where it needs to be tacked its still not sitting flush. ive checked and double checked measurements,places to grind down, and i'm kinda at a loss. its literally just about there but it seems like i have no play left at all.