First Time poster here and fairly new member. I wanted to see what people have observed on POI shifts from different surfaces.
My set up
Prone
Bipod with Ski Feet & rear bag
Dirt/Grass - This zero has not moved in 5 months, Very slight changes from breaking down and rebuilding positions but only 1/10 mil from center
Wood Deck. - I was practicing a prone off of a wood deck and I noticed a POI shift about .3 mil high and .3 mil right (I checked at 100yds to eliminate environmental factors and observed the same POI shift, tight group high right) . Went back to dirt and zero was perfect, tight group in center.
Shot a match the following weekend. Prone stage was off the deck 500yd KYL rack hit to move on. First shot high right. Made correction 3/10 low and 3/10 left remembering the POI shift from practice. Impact 4x in a row on Know Your Limits Rack from 2 MOA to half MOA at 500yds. Wind was very slight, while i know that could be a contributor to the miss right at 500, my elevation was clearly off by 3/10. BIPOD legs were NOT loaded at any angles so i do not think there were any NPA issues.
Concrete - I have not tested this yet
Anyone else observe POI shifts high on hard surfaces?
Thank you for your advice.
My set up
Prone
Bipod with Ski Feet & rear bag
Dirt/Grass - This zero has not moved in 5 months, Very slight changes from breaking down and rebuilding positions but only 1/10 mil from center
Wood Deck. - I was practicing a prone off of a wood deck and I noticed a POI shift about .3 mil high and .3 mil right (I checked at 100yds to eliminate environmental factors and observed the same POI shift, tight group high right) . Went back to dirt and zero was perfect, tight group in center.
Shot a match the following weekend. Prone stage was off the deck 500yd KYL rack hit to move on. First shot high right. Made correction 3/10 low and 3/10 left remembering the POI shift from practice. Impact 4x in a row on Know Your Limits Rack from 2 MOA to half MOA at 500yds. Wind was very slight, while i know that could be a contributor to the miss right at 500, my elevation was clearly off by 3/10. BIPOD legs were NOT loaded at any angles so i do not think there were any NPA issues.
Concrete - I have not tested this yet
Anyone else observe POI shifts high on hard surfaces?
Thank you for your advice.