Boot sizing

I am looking to purchase a pair of motocross boots. I wear a 13 or 14 shoe and work boot. I have tried to visit many shops to try on a pair in mysize and the largest size has been 13, too small. so, if everyone is willing to order them, and no one will take them back on return, how am i supposed to purchase the right size on the first attempt. I also know that each manufacturer has a slightly different size than the next. Please help!

My red wing boot is size 13
My running shoe is generally 14