Please explain...

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Please explain...

Post by igolfat8 on 12/1/2014, 7:44 pm

We usually shoot paper targets at 30' indoors because our range is only 50' in total length. Our pistols are sighted in at the 30' distance but we decided to move the targets back to 50' and everyone was shooting 1 - 3" above POA. Why is this? I would have expected POI to be low and was surprised. Keep in mind that I don't shoot BE nor have I ever been to a competition. This is probably elementary to you guys so be kind ...

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Re: Please explain...

Post by james r chapman on 12/1/2014, 9:44 pm

the bullet is still rising...

we shoot PPC at 21', and the bullets will hit low in the x/10 ring but centered at 50'
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Re: Please explain...

Post by Jack H on 12/1/2014, 10:41 pm

Are you using a dot sight mounted way above the bore?
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Re: Please explain...

Post by LenV on 12/1/2014, 10:46 pm

Yes, the bullet is still rising.... but what that means is that to defy gravity and get the bullet to the target with the poa the same as the poi you actually have to point the barrel up slightly. Depending on how far above the barrel the sights are ( steel being much less then optics) you also have to point it up to where the line of sight and the bullet path cross. This means for a very short distance ( like 30') the angle up lets you defy gravity for a little longer and the bullet will actually print higher past that distance until gravity wins and bullet drops back down across the line of sight. That is why every rifle, pistol, cannon, etc have two distances where poa and poi are the same. Once on the way up and again on the way down.

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Re: Please explain...

Post by Virgil Kane on 12/2/2014, 7:46 am

There is no such thing as bullet rise whether it's a handgun, rifle or cannon. Like OldMaster explained the gun barrel is pointed up in relation to the sights. In reality if the bore is held parallel to the ground the bullet starts falling as soon as it leaves the barrel. As mere humans we haven't figured out how to beat gravity yet, only cheat it for a few micro seconds.


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Re: Please explain...

Post by dronning on 12/2/2014, 9:12 am

The 22lr ballistics are pretty flat out to 50 yards (2.5" drop). 

Your sight height comes into play in a big way.  Lets exaggerate a little and say your dot was mounted 3" above the bore.  If you put you gun in a vise and zero'd your optic at 10 yards it would be pointed down at a pretty steep angle.  Now if you move the target out to 20 yards and looked in the optic with the gun still in the vise the dot would be way below the center of the target.  As several posts have said moving from 10 to 20 yards you are raising the muzzle when you center the dot on the target and the shot goes high.

- Dave
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Re: Please explain...

Post by igolfat8 on 12/2/2014, 11:57 am

Jack H wrote:Are you using a dot sight mounted way above the bore?
Yes, I use a Burris Fast Fire III but it is lower to the bore axis than some tube style dots.

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Re: Please explain...

Post by igolfat8 on 12/2/2014, 12:03 pm

Thanks for the detailed explanations guys.

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Re: Please explain...

Post by james r chapman on 12/2/2014, 3:18 pm

you can call it what you want, but, the bullet strikes lower at 7 yards than at 50' because it is rising. it it rising because you elevated the barrel, but, it is rising....
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Re: Please explain...

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