I see many people complain about POI shift and I think many experience it but don't want to say anything about it for various reasons. That is from all levels of air rifles, from budget to expensive top tier rifles.
What is the reasons for that ? Here are some thoughts that can cause it, singular or any combination of it.
I will update this list as more input are given and mark extra input with *.
Possible solution marked with
.
Needs solution
Weather / atmospheric conditions, excluding the obvious wind drift / air turbulence.
- Temperature changing metal expansion / contraction letting barrels curve to one side. (I found that with air rifles as well as PB rifles after it sits in the sun for a while.) - Keep the rifle out of direct sunlight.
- Air pressure causing the projectile to fly differently through the air.
- Temperature altering the telescope internals. - Try to keep the scope out of the heat of cold.
The rifle itself.
- Barrel fixed in position properly, all fasteners are tight, but still movement with handling / bumps, especially thinner barrels.
- Barrel to thin causing it to have more vibrations / harmonic disturbance that change with external conditions. * Thick/solid barrels, and secure fixation of the barrel.
- Barrel is dirty. - Clean the barrel properly.
- Internal air movement / turbulence in silencer / silencer not centered.
- Obvious things like loose hardware. - Tighten all fasters and test for movement.
- Breach seal. - Replace breach seal and oil regular with silicon oil.
- 1st Shot low POI. - Regulator creep cause high plenum pressure, causing the hammer not being able to open the valve enough for for power shot. Shoot a few dry shots to bring pressure back to setting and after that continue to shoot with projectiles.
* Faulty regulator. - Service or replace regulator.
* Bent probe. - Replace probe.
* Magazine not indexing correctly. - If possible, adjust magazine. - Buy another magazine. - Single load.
* Bad design.- Other than buying a better rifle, see if you can do some work to improve yours.
Telescope.
* Poor parallax adjustment. - Adjust parallax.
* Ocular lens loose. Tighten lens.
Ammunition.
- Ammunition not consistent - weight, diameter, balance. - Sort ammo
- Pellet design not meant for longer distance. - Use different pellets.
- Ammo not tested to see what shoot best from rifle. Test different ammo and even different batches of same ammo.
- Low quality ammo. - Buy better ammo and test.
- Damaged ammo. - Discard damaged ammo.
Shooter.
- Mostly shooter input differences from session to session. (Many times my problem.
) - Practice for consistency.
- Rifle canting. - Install scope level and always keep the rifle level.
* Inconsistent cheek weld. - Practice for consistency.
Other.
* Contaminated air supply. (edit: This will include moist in the air.) Improve filtration.
What else? Are there other reasons for POI shift ? What are the most common problems?
What is the reasons for that ? Here are some thoughts that can cause it, singular or any combination of it.
I will update this list as more input are given and mark extra input with *.
Possible solution marked with
.Needs solution
Weather / atmospheric conditions, excluding the obvious wind drift / air turbulence.
- Temperature changing metal expansion / contraction letting barrels curve to one side. (I found that with air rifles as well as PB rifles after it sits in the sun for a while.)
- Keep the rifle out of direct sunlight.- Air pressure causing the projectile to fly differently through the air.
- Temperature altering the telescope internals.
- Try to keep the scope out of the heat of cold.The rifle itself.
- Barrel fixed in position properly, all fasteners are tight, but still movement with handling / bumps, especially thinner barrels.
- Barrel to thin causing it to have more vibrations / harmonic disturbance that change with external conditions.
* Thick/solid barrels, and secure fixation of the barrel.- Barrel is dirty.
- Clean the barrel properly.- Internal air movement / turbulence in silencer / silencer not centered.
- Obvious things like loose hardware.
- Tighten all fasters and test for movement.- Breach seal.
- Replace breach seal and oil regular with silicon oil.- 1st Shot low POI.
- Regulator creep cause high plenum pressure, causing the hammer not being able to open the valve enough for for power shot. Shoot a few dry shots to bring pressure back to setting and after that continue to shoot with projectiles. * Faulty regulator.
- Service or replace regulator.* Bent probe.
- Replace probe.* Magazine not indexing correctly.
- If possible, adjust magazine. - Buy another magazine. - Single load.* Bad design.
- Other than buying a better rifle, see if you can do some work to improve yours.Telescope.
* Poor parallax adjustment.
- Adjust parallax.* Ocular lens loose.
Tighten lens.Ammunition.
- Ammunition not consistent - weight, diameter, balance.
- Sort ammo- Pellet design not meant for longer distance.
- Use different pellets.- Ammo not tested to see what shoot best from rifle.
Test different ammo and even different batches of same ammo.- Low quality ammo.
- Buy better ammo and test.- Damaged ammo.
- Discard damaged ammo.Shooter.
- Mostly shooter input differences from session to session. (Many times my problem.
) - Practice for consistency.- Rifle canting.
- Install scope level and always keep the rifle level.* Inconsistent cheek weld.
- Practice for consistency.Other.
* Contaminated air supply. (edit: This will include moist in the air.)
Improve filtration.What else? Are there other reasons for POI shift ? What are the most common problems?
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