DOPE shifted during match

[CShooter92]

Hey everyone,

I have a quick question about what can cause your dope to shift during a match.

I shot on Saturday and my dope out to 650 yards was right on in the morning. Around lunch time, some heavy rain rolled in and I found that my dope was off almost 1 MOA in elevation. Not sure if this was due to the humidity, different pressure, a slight head wind?

Once I got home I checked the torque on all my scope screws and a couple tightened up a quarter turn. Haven't had a chance to run back out to the range to check my zero though.

 

[hlee]

My guess is low pressure associated with the storm. I had a similar shift, but was due to temp change from morning to early afternoon. I had dead center at the beginning of the match but was using a 6 o'clock hold by the afternoon to make hits.

 

[flyer]

Next time, check that before confirming zero.

 

[ARobinson]

For me,

High Impacts
1) Weak position on a barricade, high impacts vs driving the bipod hard in prone
2) New Barrel speeding up. My barrel speed prior to match at 2850 I noticed high impacts and got 2875 after the match, now its 2900 at 400 rounds
3) Temp increase from morning to afternoon leaving ammo sitting in the sun

Low Impacts = Target distance marked incorrectly on the course of fire

 

[Deleted member 10043]

Vertical deflection of wind.