SFP POI 2 questions

[D Lee]

Will try to make these SFP scope questions as simple as possible. Pls understand, NOT asking to compare MIL / MOA / FFP / SFP.


Here are the HYPOTHETICAL particulars at the bench.


1. SFP scope – 6x24x50 – Xmas Tree Reticle.

2. Scope on 24x at 100 yards.

3. Under MOA groups follow.

4. I use the tree reticle hashmarks for 300, 400 & 500. ALL POI’s line up nicely. Yes, I know, only in a perfect world. Remember, I said hypothetical )

So far – so good.


4. Turn the power down to 6x (or 8x, 10x, 12x etc).

FIRST QUESTION: Will my POI change at 100 yards at the lower power levels?


SECOND QUESTION: At the lower power levels – will my tree reticle hashmarks / POI’s still work at 300, 400 & 500 yards?


Just answers to those 2 questions would be most appreciated.


Thanks.

 

[jfk69]

1.) Maybe. Sometimes a change in zoom will cause a minor change in POI.

2.) No

 

[MThuntr]

1) No...if that happens get a new scope
2) No...that's the advantage of using a FFP vs SFP

 

[Marshfly]

Will try to make these SFP scope questions as simple as possible. Pls understand, NOT asking to compare MIL / MOA / FFP / SFP.

The answer to your second question is the exact reason most of us have switched to FFP.

I would be dialing for elevation, ESPECIALLY on a SFP scope. Ignore your reticle.

 

[D Lee]

The answer to your second question is the exact reason most of us have switched to FFP.

I would be dialing for elevation, ESPECIALLY on a SFP scope. Ignore your reticle.

Thanks. Understood on your FFP AND SFP comments. Helpful. Went to FFP - came back to SFP in spite of its disadvantages (?). Works better for me personally. New to all this "dialing..." a work on progress for sure.

As for folks answering my 2 questions? YOU DID. Thank you.

 

[SomeJackassOnAForum]

Will try to make these SFP scope questions as simple as possible. Pls understand, NOT asking to compare MIL / MOA / FFP / SFP.


Here are the HYPOTHETICAL particulars at the bench.


1. SFP scope – 6x24x50 – Xmas Tree Reticle.

2. Scope on 24x at 100 yards.

3. Under MOA groups follow.

4. I use the tree reticle hashmarks for 300, 400 & 500. ALL POI’s line up nicely. Yes, I know, only in a perfect world. Remember, I said hypothetical )

So far – so good.


4. Turn the power down to 6x (or 8x, 10x, 12x etc).

FIRST QUESTION: Will my POI change at 100 yards at the lower power levels?


SECOND QUESTION: At the lower power levels – will my tree reticle hashmarks / POI’s still work at 300, 400 & 500 yards?


Just answers to those 2 questions would be most appreciated.


Thanks.

First ?: You may see a slight shift in your POI because your reticle now covers 4x as much space on the target. I would say that you're more likely to experience a shift at 100 yds from looking at the target at 6x zoom instead of 24x zoom due to your ability to precisely aim at the same point being affected by the lower mag than by anything inside the scope or even the reticle.

Second ?: How useful your tree is depends on whether your tree is a ballistic compensating tree or a Mil / MOA tree.

If your tree is a drop reticle set up for a given cartridge, it will only have any functionality at all at max power.

For an MOA or Mil tree, your values at any power will be (Max Power / Current Power) x Value at Max Power = Value at Current Power

So a 1 mil hold at 24x becomes a 2 mil hold at 12x and a 4 mil hold at 6x. (same ratios for MOA as well, of course)

In other words, if you have a Mil or MOA based crosshair and you learn your yardage corrections in mils or MOA, you can use the reticle at any power, as long as you know what power you're on. However, your 300 yd hold at 24x will not be the same as your 300 yd hold at 6x.

 

[WSMHNTR]

1. No it will not change center reticle POI (Or at least shouldn't)
2. If your reticle sub tensions are 300, 400, 500 at 24x they won't even be close at the lower magnification. This is where FFP shines over SFP scopes but they can be very fine and hard to see on low power under less than ideal lighting conditions.

 

[D Lee]

SFP............. 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 is still valid - yes?

Thanks.

 

[ScreamingPotato]

SFP............. 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 is still valid - yes?

Thanks.

The tree can still be useful at all powers if you take the time to calculate and document what's what.

 

[LongWayAround]

SFP............. 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 is still valid - yes?

Thanks.

No.

Your reticle subtensions are only valid on the power specified by the manufacturer.

On any other power, you will have to use some jackass's math to convert them.

 

[D Lee]

LWA...
Thank you. THAT answers my question. I was hopeful...but you confirmed what I thought.

WSM...
On low powwr, can't see the reticle against a dark background...why I went back to SFP.

Much appreciate all the responses.

 

[Macintosh]

vortex Viper PST Gen II| 5-25x50 SFP.
On max magnification 25 , zero on 100 yards i do on 100 - 10s
200 yards -10 s
300 yards -10 s
But on 400 yards I can’t hit the target it goes down like 15 inches .

Its not clear to me what uou mean. Could you explain this^?

What is “s”? “10s”?