I would like to say, YES, the paralex on the Vortex can be altered. I am now the proud owner of the Vortex Viper PST 6-24x50 ffp with ebr2c mrad reticle. The Vortex scopes do come with a minimum paralex of 50 yards. Which is a shame for airgunners like myself that like to shoot upwards of 15 yards. I live in England and there are only 2 main vortex dealers, one of which told me it IS possible to alter and shorten the paralex. After doing a bit research on the subject I found there was very little on altering paralex on scopes. I came across 2 people that said the same thing. And tried it myself and it worked! Unscrew and remove the objective lens cover cap and turn the lens carrier counter clockwise. Do it carefully and in increments of quarter turns until your desired minimum paralex distance. Before doing this I would advise that you set up readable paper targets every 5 or 10 yards from say 15 yards out to 60 yards. Remember when you alter this make notes on where your reparalexing it as you will have to put new markings on the paralex wheel. And bare in mind when you shorten the minimum paralex distance, you also shorten the maximum paralex distance. Good luck.