should q3131 zero the same as q3131a or will the POI be off?

Looking at my chrono data from the past shows that Q3131 is about 40 fps slower than the Q3131A. This variance could very well be due to my particular lots of ammo, but even with this small difference in speed POI should be very close to the same.

Disclaimer: The only way to know for sure is to shoot some of both in your own gun.

Any different lot of ammo shoots differently. Sooo- if you have a thousand rounds of Q3131a, lot # 123, sight it in for that lot. Your next case of Q3131a, Lot #1234, well, sight it in for that one too. It may not change much, but it probably changed a little. So the same manufacturer with different lot#'s will indeed shoot differently. Probably not by much, but if you want to be spot on, check it on paper to be sure––-always. If you have a totally different brand of .556, the same goes for that of course, because it  probably shoots quite a bit differently than the last batch you were firing.