I don't think OU vs sxs makes a difference. What does make a difference, however, is the position of the single trigger. Some are very close to the rear of the trigger guard, much like the rear trigger on a DT gun. Others are much farther forward. I'm mostly a DT guy, and on some of those with a good bit of space between the single trigger and the guard, I'll occasionally forget it's a ST gun and find myself pulling the guard for a 2nd shot. Never seems to work, no matter how hard I pull!