My sight or my sites?

[sketch]

Watching the vid unforgiven posted previous I realized I might have a parallax problem? I shoot a Nikon 2.5/10x42 BDC long range comp but can't dial this in closer than 2 in. groups :( at 100 yds to my knoledge there is no parallax adjustment should I get better glass with parallax or glasses?

[MONTANA308]

Could be the gun/ammo