Recently went out to sight in a Nikon p223 3x9 optic today but it didn't want to hold a zero. I'm using it on a 14.5" suppressed AR with 55gr PMC ammo. I was only able to get two shots to group where I was aiming but then it would start giving me errant shots. I'm no expert marksman but I can hit a bullseye at 50yds with a RDS no problem without the results I was getting today. All the bolts are tight on the mount as well. I can't figure out why I would be having this hard of a time sighting in a rifle. Anyone else have a problem like this?