POA and POI

Rilow

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Apr 24, 2016
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Hope this isn’t a dumb question but wouldn’t be the first one I ever asked. When doing load work for a rifle that is sighted in with a good shooting factory load, as working through powder charges poi may be 3in low n to left (just an example) and as I work through charges I’ve noticed the poi will work to line up with poa on the horizontal. Does this mean anything or should it even be noted?
 

25WSM

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That is normal. Your barrels muzzle rises up and down with the harmonics. As you change your charge weight the bullet will exit the muzzle at different times while the muzzle moves up and down. If you work through a ladder test you will see the bullets go up and down and then back again. So as the bullet exits at the top of the swing it will go high and then as you increase the speed the bullet will actually start to hit lower until you reach the bottom of the swing. Then it will start coming up again. So once you have your load just adjust your poi to where you like it.
Shep
 

Rilow

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Maybe I didn’t explain it very well I’m talking about left to right
 

25WSM

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Barrel harmonics don't just move up and down. In a perfect world it would. I've noticed just a small amount of left right when doing I've test. Nothing more than say 1/2 inch on a bad one. Is your barrel completely free floated? Could just be your barrel has more side to side harmonics than normal. If you come up with a load that shoots real good I wouldn't worry about it.
Shep
 

CatShooter

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Hope this isn’t a dumb question but wouldn’t be the first one I ever asked. When doing load work for a rifle that is sighted in with a good shooting factory load, as working through powder charges poi may be 3in low n to left (just an example) and as I work through charges I’ve noticed the poi will work to line up with poa on the horizontal. Does this mean anything or should it even be noted?


It means nothing - find your load and adjust your scope.
 

MagnumManiac

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Feb 25, 2008
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A barrel oscillates during firing, essentially it vibrates in a vertical oval shape.
It is rare to find 2 powder combos with the same bullet to shoot to the same POI.

When I shoot for groups with a new powder, I do not adjust my scope unless it is way off from POA.

Cheers.
 
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