F T/R Competition Changes in POI vs. POA

[Oldmauser]

1. Rifle: Krieger barrel 6.5 CM, Howa Action (trued etc.), Trigger 0.6kg, Vortex Golden Eagle, Contessa rings.
2. I am using RWS Elite ammo.
3. I spent an hour to sight in the rifle at 100m exactly on week before my match. See the photo attached.
4. During the match (no wind) my hits (POI) were consistently lower about 2 cm below the POA. I am wondering where could this change come from. I was using exactly the same ammo, the same front rest etc.

Should I start with checking my rings? Was it the ammo?

 

[XTR]

At 100m

Shooter
Parallax
temperature (probably not the whole 2cm)

And, that target is not zeroed to center if you are holding center. It's off either up or down (is the image right side up) by at least one bullet diameter, maybe 2.

The shooter can influence the POI by the way you hold cheek pressure, grip all make a difference..

Were you on a bench when you zeroed?
Were you on a bench or the ground when you shot?

 

[Oldmauser]

Yes, I was on the bench both times. Could you explain "that target is not zeroed to center if you are holding center. It's off either up or down (is the image right side up) by at least one bullet diameter, maybe 2."?

 

[XTR]

If I understand correctly that is your target from zeroing the rifle, and you were holding at the center of the target, then the holes in that target (POI) are below your point of aim. Your group is centered low. The red line is where I assumed you held, the group is centered below that.

 

[smoothy8500]

It's why F-class, Palma, High Power, International Smallbore, etc, all give us at least two sighters....

 

[Gee Kay]

difference in altitude?

 

[Joel Danielson]

Was the match shot at the same distance as what you sighted the rifle for? Was it the same range? As others said, were conditions the same (temp, humidity, altitude, etc...)? If you had a consistent headwind, it would contribute to lower impacts as well. Cheers

 

[BrienM]

Sunny vs overcast seems to affect my zero.
Conditions others have mentioned too..

 

[PracticalTactical]

Wind direction causes vertical shift as well as lateral. Typically wind pick up and let off result in a pattern from 9:30 to 3:30. So that could account for it depending on wind speed and direction.

On flat land a head wind causes low impact, tail wind causes high impact. Although a head wind would cause high impact if shooting across a valley.

As stated above... Cloud cover, or overcast vs direct sun causes verticals... old saying is lights up sights up or light down sights down

You may even find some verticals related to muzzle velocity changes based on when you last cleaned the barrel and how well you cleaned it. A real clean barrel shoots slow and takes a few shots to get back to normal. That's why we have a blow off period at the start of a match.

 

[Marine52]

At 100m

Shooter
Parallax
temperature (probably not the whole 2cm)

And, that target is not zeroed to center if you are holding center. It's off either up or down (is the image right side up) by at least one bullet diameter, maybe 2.

The shooter can influence the POI by the way you hold cheek pressure, grip all make a difference..

Were you on a bench when you zeroed?
Were you on a bench or the ground when you shot?

this analysis is spot on. Consistency is key. A change in shoulder pressure will impact your verticle.