Trouble with my 100 yard zero.

[Victorfmr24]

I was checking my 100 yard zero a few days ago. My gun was off to the left an inch so I rezeroed it. There was quite a mirage but I didn't think it would effect me at 100 yards. This afternoon when I was shooting through a chrono my zero was off to the right an inch and a half. Could a mirage move my poi left an inch at just 100 yards? I was shooting from the prone with proper cheek weld both times

 

[FearNoWind]

Mirage generates an optical illusion that makes your target appear to be in a different place than it actually is. Depending on the density of the mirage (boil) it could easily generated an error of the severity you describe.
There are, of course, other possibilities (scope quality, mount security, etc.)

 

[Victorfmr24]

I was worried it was my scope. I have a nightforce nxs. I'll shoot it again early some morning to be sure. Thanks. I think the mirage must have been worse because it was a warm day and I was shooting over melting snow.

 

[kshunter]

I would venture to say you were experiencing the affect of the mirage. Snow on the ground with sun or a warm front can generate some intense mirage even at 100 yds. Your scope is definitely a quality optic unless it got hit with a hammer it's probably ok!

 

[WildRose]

Check your parallax focus

Turn your scope power down. Take a shot. Turn your scope power back up and take a shot.

If there is a shift in POI between the two it'll confirm whether or not mirage is the problem.