Okay, so I usually shoot 62gr M855 out of my Sig556. It currently sports an EoTech 551 and is very accurate. (well enough for me) I recently tried out some 55gr Federal HP rounds that I keep loaded for home defense to make sure they cycled fine. However while shooting the first 5 rounds of this ammo (the rest of the mag had the M855 in it) I could not hit the cans I was aiming at from 80 yards. Once they were out and I was shooting the M855 I was hitting exactly where I was aiming. So not being a super accuracy person (I just like to blow off steam and plink) should there be a huge POI change between the two ammo types? FYI my sig has a 1/7 twist barrel.