ive never played at vangard, so you can take this with a grain of salt if you want. but i do do some close stuff sometimes and i have been playing for a few yrs or so. get whats comfortable for you, something that you know that you can handle well, cause in the end your the one that has to be happy with your gun. with that being said for cqb type play like vangard, you want your gun as small and as manuverable as possible. a 6-9inch inner barrel will give you all the range that you need in a place that small. 6-7 inchs is probly more then sufficiant. more inportant then the gun is your targeting skills. find a gun that you can put on target as fast as possible. a gun that feels comfortable in your hands. try to find someone that has the gun that you are thinking buying and see if they will let you put hands on thiers for a lil bit. see how it feels. good luck in your hunt.