Stupid question... Have you shot a hand gun before? Its not uncommon for folks who've never shot handgun to flinch and such and induce misses.
If you've shot handgun and can hit, most likely at that range the optics were "adjusted". Rental guns get the crap beat out of them. Even with dot focus vs target focus at that range you should be doing much better. Points 1 and 2 from LivingUpNorth are the biggest hitters, with #2, IMO, being the biggest. The dot and irons are NOT one same plane. Trying to super impose them will be an issue, even if you're doing it subconsciously.
ETA: ignore first question, just saw your response above.