The gun will go to the bottom of the case and it's trigger guard or lever will hit the zipper and be damaged.
Here is an example of one:
http://www.cabelas.com/product/Cabelas-Heavy-Canvas-Scoped-Rifle-Case/707156.uts?Ntk=AllProducts&searchPath=%2Fcatalog%2Fsearch.cmd%3Fform_state%3DsearchForm%26N%3D0%26fsch%3Dtrue%26Ntk%3DAllProducts%26Ntt%3Dsr-046%26x%3D0%26y%3D0%26WTz_l%3DHeader%253BSearch-All%2BProducts&Ntt=sr-046