SFP scope - POI???

[Taidog1]

I'm stepping from SFP into / learning dialing with MIL and FFP. I now have a question about my SFP hunting scope.

I've sighted in my SFP scope @ 100 yards (or 200) using the 15x power setting. Done. Good groups.

Now - I go to the range or field and change my power setting to 6x (or 4x or 10x). I don't touch my elevation or windage trurret. Will my POI - my accuracy - hold at 100? I'm not talking about bullet fps and trajectory ballistics - just POI at 100 at a diffent power setting. I've spent a lot of years believing I knew this. And I MAY be right that POI will hold at different power settings on my scope?? Right?? Killed a good bit of game at many yardages doing this. Always worked.

I just want to make sure I have this right.

Thank you. Much appreciated.

[Whynot]

I'm stepping from SFP into / learning dialing with MIL and FFP. I now have a question about my SFP hunting scope.

I've sighted in my SFP scope @ 100 yards (or 200) using the 15x power setting. Done. Good groups.

Now - I go to the range or field and change my power setting to 6x (or 4x or 10x). I don't touch my elevation or windage trurret. Will my POI - my accuracy - hold at 100? I'm not talking about bullet fps and trajectory ballistics - just POI at 100 at a diffent power setting. I've spent a lot of years believing I knew this. And I MAY be right that POI will hold at different power settings on my scope?? Right?? Killed a good bit of game at many yardages doing this. Always worked.

I just want to make sure I have this right.

Thank you. Much appreciated.

Yes- the center crosshair point of aim does not change when you adjust the power... doesn't matter if you are on lowest power or highest power.

What does change are the subtensions (the reference points below the center crosshair) as you change magnification. (if you only have a duplex reticle then this doesn't apply). But if you have a reticle that has different aiming points- be it a mil, moa, or bdc- then those additional aiming points and wind holds are only correct at one magnification.

Think of it this way- if you are looking at a target and from top to bottom it covers 4 moa lines at max power.... now you power down. Because you decreased power the target now appears smaller- but the reticle did not change so it now only covers 2 moa lines. That is how a sfp scope works... if it has a .2 mil reticle set to be correct on 20x then those reticle marks will actually become .4 mil if you adjust the power to 10x.

FFP changes the size of the reticle as you adjust the power- so if you are looking at a target that is 2 mil on 20x and zoom down to 4 power the target would still cover the same 2 mil on your reticle.

[Taidog1]

Yes- the center crosshair point of aim does not change when you adjust the power... doesn't matter if you are on lowest power or highest power.

What does change are the subtensions (the reference points below the center crosshair) as you change magnification. (if you only have a duplex reticle then this doesn't apply). But if you have a reticle that has different aiming points- be it a mil, moa, or bdc- then those additional aiming points and wind holds are only correct at one magnification.

Think of it this way- if you are looking at a target and from top to bottom it covers 4 moa lines at max power.... now you power down. Because you decreased power the target now appears smaller- but the reticle did not change so it now only covers 2 moa lines. That is how a sfp scope works... if it has a .2 mil reticle set to be correct on 20x then those reticle marks will actually become .4 mil if you adjust the power to 10x.

FFP changes the size of the reticle as you adjust the power- so if you are looking at a target that is 2 mil on 20x and zoom down to 4 power the target would still cover the same 2 mil on your reticle.

Whynot...

Thank you very much for the confirmation and plain language explanation. What you said after your text in red above..........I'm still learning. Definitely a work in progress. I'm sold on FFP MIL for LR "target" work - for all the good reasons.

Just not sure I need a FFP MIL scope for Hunting??? Over many long years, the game I've taken have been inside 400 yards. That said...knowing how to dial correctly would be an advantage down the road should I only have an ethical LR opportunity.

Have a good day.

Cheers!!!

[Taidog1]

WhyNot,

If I sight in using a particular power (be it 8x - 10x - 12x - 14x) as long as I'm on that particular power that I sighted in with - each of my hashmarks apply - yes?

Thanks.

[charlie b]

Yes.

[Taidog1]

Yes.

Hey Mr. Charlie...

Thank you.

I posted this same question on another forum - gentleman came back and said hashmarks are only good at the power level the manufacturer sets - typically max power? OK............................now what??

Just trying to better understand dialing with my SFP scope. I don't mind some trial and error on my own but appreciate all the help I can get.

If the hashmarks only work on the manufacturer's setting...so be it. I'll live with that and use some common sense hold-overs with the scope on a lower power out to maybe 400 yards and call it good.

If you are right Mr. Charlie, then I could sight in at a power level a lot closer to the hunting situation I would be facing. Say, maybe 4x or 6x - put it on that level and dial from there???????? IF I can do that???

Sorry if I'm confusing anyone trying to help.

THANKS.

[charlie b]

Just know that those hash marks will not be as marked on the scope (if it has any numbers).

Set the magnification you want. Zero it. Figure out which hashmark shoots at which range. Done.

Yes, you can calculate the range for each of the hash marks, but, you have to take the original mark measurement, then adjust for the new magnification. For example, if you have a hash mark that is 2MOA at 12x and want to use the scope at 6x, that hash will now be 4MOA.

The dials on the scope are a different animal. If you use the dials they stay the same no matter the magnification. Only the reticle is messed up when changing magnification.

Yes, it can be confusing. All that is why people who use these 'professionally' choose FFP scopes. They can also use 'bullet drop' reticles calibrated for their cartridges and not worry about magnification changes. A 1MOA hash mark is 1MOA no matter what magnification they use.

[charlie b]

I hunted with a plain duplex scope for so many years that this kind of stuff was not even a consideration.

Zero at my 'point blank' range. If the target was beyond that I'd have time to increase the zoom and dial in any elevation correction I needed. No hash marks to worry about.

[Taidog1]

I hunted with a plain duplex scope for so many years that this kind of stuff was not even a consideration.

Zero at my 'point blank' range. If the target was beyond that I'd have time to increase the zoom and dial in any elevation correction I needed. No hash marks to worry about.

For 6 decades...me neither. Shoot the flattest cartridge I owned and go hunt. No complaints. JOC did the same and look what he accomplished!!

I heard what you said above. Thank you. Plain language works better for me than math explanations. What is so simple for many just complicates things for me. Hopefully in time all this will make sense. :-) Hope to be at the range later this coming week.

Be safe and thanks again.

Cheers.

[charlie b]

YW, and good luck with your shooting.

[PhilC]

I hunted with a plain duplex scope for so many years that this kind of stuff was not even a consideration.

Zero at my 'point blank' range. If the target was beyond that I'd have time to increase the zoom and dial in any elevation correction I needed. No hash marks to worry about.

Yep, and I did the same when I was still hunting, my "point blank range" was also the max distance I was comfortable shooting.

[Taidog1]

Yep, and I did the same when I was still hunting, my "point blank range" was also the max distance I was comfortable shooting.

Amen Phil.

For LR Coyotes...it would be nice to know how to add another 200 / 300 yards with DRT accuracy. I have the gear. I'm the work in progress.