hi all, i bought one of these great lil shooters a couple weeks ago, threw on a cheap scope took it to the range to sight it in, no problems, 2nd range trip yesterday & its shooting all over until the scope came off the rail, do i need to replace it with a better rail or just tight the f#*k out of it? lol i've read/heard on here somewhere that scopes can "walk" off the rail on 795's, any input is most appreciated