Change in POI when zooming

[JimNM]

To be an accurate shooter, one must be able to use the right words to accurately diagnose the problem. POI shift is a gun/pellet issue, IOW ballistics. Codling (for the pedantic spelling champion who has never had auto-correct help from their phone) and baby talk to make a shooter feel better does not allow them to grow into being a better shooter. Tough love - it's the only way to really show that you want them to improve.

 

[Sqwirl57]

To be an accurate shooter, one must be able to use the right words to accurately diagnose the problem. POI shift is a gun/pellet issue, IOW ballistics. Coddling and baby talk to make a shooter feel better does not allow them to grow into being a better shooter. Tough love - it's the only way to really show that you want them to improve.

Incorrect. Most sources on the web do refer to this phenomenon as a POI shift due to the POA being perceived as the same. If you want to be a pedant though, you do you. The fact of the matter here is that everyone knew what the OP was referring to. Whether you like what it was called or not really doesn’t much.

Now if you want to share a reputable source for what you're saying I'm all eyes and ears. It still won't change the fact that getting high and mighty over a little grammer is not helpful in the least though.

 

[nervoustrig]

Coddling and baby talk to make a shooter feel better does not allow them to grow into being a better shooter.

Your prior appeal for using the correct and precise terminology was perfectly reasonable, but this charge of “coddling and baby talk” is not an earnest representation of anything that was actually happening.

 

[Ezana4CE]

I’m far from an expert here, but my immediate thought was that the OP was shooting using a second focal plane scope. Changing points of impact at various magnification levels is exactly why I don’t like them for hunting, especially for short to medium-range hunting. The necessity of learning and writing down various holds for different distances is a bit much. Remembering it all is quite the task. Imagine that it creates a similar task for those that like to dial turrets.

 

[JimNM]

Incorrect. Most sources on the web do refer to this phenomenon as a POI shift due to the POA being perceived as the same. If you want to be a pedant though, you do you. The fact of the matter here is that everyone knew what the OP was referring to. Whether you like what it was called or not really doesn’t much.

Now if you want to share a reputable source for what you're saying I'm all eyes and ears. It still won't change the fact that getting high and mighty over a little grammer is not helpful in the least though.

"Most sources on the web" are wrong, being in the majority and still being wrong does not make those sources any less wrong.

The sights, scope or red dot has exactly nothing to do with POI. Impact is a mechanical issue. Where the projectile hits - on target or not -.

"Aim" is an visual interpretation of where the shooter wishes POI to happen, although often time it is not. That separation of POI and POA is where the OP is having trouble.

I don't mean to repeat myself, but it was not apparently understood the first time.

POI is only a reflection of physical forces, known all over the web (haha!) as ballistics. Interior and exterior ballistics. Inside the gun and outside the gun, including wind and spin drift. The gun. The pellet. Locked in place, with a scope on, with a scope off, with a scope on backwards or with a scope on that has the lense caps glued in place.... The POI will be the same (group wise) as long as the ballistics are the same. The POI cannot be changed at all by a change in any kind of optics. Optics don't shoot the pellet. The gun does.

Remove the scope, and guess what? The POI does not change.

I am glad y'all want to help the guy out. It is my firm desire to see the OP get a good solution.

Pedantic or not, accuracy is my goal. Ignorance is not my friend.

 

[Firewalker]

Your center zero should not change with magnification. If it does, you have a bad scope. If you are using the Mil Dots or ballistic reticle for holdovers with a second focal plane scope, they will only be accurate at one power level.

Agreed, center stays centered but the dots no longer represent the same placement.

 

[Gambler]

Ill try to read everything here and understand it, all i want to know if the scope im using is broken or if this is normal with a sfp scope. When I put my ffp scope back on i hit where i aim on any magnifications, thats not possible with my sfp

 

[nervoustrig]

Jim's position is 100% correct in terms of the distinction between POA and POI. However I would argue that in the context of this discussion, it is a distinction without a difference.

If the cause of the discrepancy were unknown, the troubleshooting steps would need to include some effort to figure out if it was the gun's fault (POI shift) or the scope's fault (POA shift). However the OP had already found evidence it is the scope causing the discrepancy. And like any of us, he's concerned with the end result...where his groups end up. The POI. Basically every effort we make converges on producing a repeatable, predictable POI so it's completely understandable how this problem could be casually described as a "change in POI".

How many times have you read someone describe a sighting in session and saying something like, "At first it was hitting about 2 inches low so I dialed the turrets to bring the POI up"? No one says "It was hitting 2 inches low so I dialed the turrets to move the POA down." Technically the latter is correct, but it sounds ridiculous because no one uses that language.

So knowing since the very beginning of the thread that the problem follows the scope, every question and suggestion had something to do with the scope. No one has been confusedly asking him to check the barrel's grub screws or the barrel band or anything of that nature. A gentle reminder that, "Hey you know it's actually a POA shift, not a POI shift" is all that was needed.

 

[Airgun-hobbyist]

Ill try to read everything here and understand it, all i want to know if the scope im using is broken or if this is normal with a sfp scope. When I put my ffp scope back on i hit where i aim on any magnifications, thats not possible with my sfp

It sounds like the scope is bad. There's a factory lifetime warranty, so sending it in would be ideal.