I've been shooting my scoped rifles alot lately in preparation for our deer rifle season next month. I'm having a heckuva time getting my crosshairs level. Everytime I get them adjusted to where they seem level I will, in time, notice that they seem to be just a little bit off, which drives me nuts. The rifles shoot just fine, better than my meager abilities can hold, I just hate looking through the scope and noticing that the cross hairs are tilted a bit. I shoot right handed and am right eye dominant. I don't have any tools or techniques for levelling the crosshairs other than just putting the rifle on a rest and trying to get them as visually straight as I can. Any suggestions here? The scopes in question are a Swift 1.5-4.5x20 mounted with Burris bases and rings on a Marlin 336 and a Burris Fullfield II 3-9x40 mounted with Leupold bases and rings on a Howa 1500.