how to fix - Point of impact change due to temperature

[Namhunter]

I have a 338 Lapua which groups at 1/4 MOA.
The problem I am having with the rifle is that the Point of impact changes by 2 inch at 200m when the temperature goes below 10 degrees.

Does someone know what the problem might be and how I can fix it?

[Namhunter]

The groups however stay constant just move around with the temperature changes

[Gawie(13mm)]

Ek dink nie die probleem lê by jou geweer as sulks nie tensy daar 'n drukpunt tussen die kolf en die loop is.

Hoe stoor jy jou ammo tydens die tyd wat jy skiet?
Probeer om die ammo in 'n koelsak te hou en laai dan enkelskoot uit die sak. Ammo se temperatuur sal dan meer konstant bly.

[Gian_dP]

What bullet/propellant are you using?

Have you measured muzzle velocity of the groups that impact low?

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Streloc simulation with temp sensitivity of 5.8 gives you more or less the change in POI.

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[Namhunter]

Thanks for your advice - the POI changes with temperature which is directly linked to the change in Velocity. Will try the Vihatavori to see whether it is more consitent