I know this thread is long dead, but I figured I would get closure on this issue.
I have done something strange in order to help my right eye astigmatism.
I take off my glasses the day before I have a qualification range, let my eyes adjust to not having corrective lenses. The morning of the range my eyes are adjusted to not wearing anything and I don't have to squint.
I placed all five of my zero and grouping shots directly within the inner circle of a 25meter M16 zeroing target first time.
I qualified my best ever score of 36/40, which is expert. My eyes were adjusted to not having anything correct them, I was able to actually see the 300meter target without the blur! I felt my misses, it was because I jerked the trigger, not because of blurry targets or anything visual.
I did this because I'm deployed and cannot wear contacts. When I go home I can try wearing them and I know that it will obviously help my astigmatism, but this is a fix for now!
Thank you to everyone for your help and advice!