Because of the scarcity of ammo I have to just buy what I can find when I can find it. I have both 223 and 556 of different brands all 55gr. I am going to the range tomorrow to sight in a new set of iron sights and scope. Which should I use to sight in? How much of an accuracy difference can I expect to see between the two? I would expect whichever one I sighted in with the other would be off at least a couple inches, am I correct? I know the obvious answer is to sight in with the one I plan on using the most, but right now, for a while at least I am just going to get what I can get.