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Long Distance Shooting Discuss tools, techniques, tips and theories of long distance shooting

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  #1  
Old 03-27-2017, 10:06 PM
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Default SFP vs FFP for long range

So this is less of a question and more of a helpful hint for people trying to get out to extended long range. To some people this will be obvious to others it's something they won't have considered. Either way it's good info. I'm using a 308 as an exaggerated example.

Lets say that you have a FFP scope with an advertised 30 mils of travel like a SWFA 5-20x50 HD, you put it on a 60 moa riser and zero it at 200 yards. If you were shooting a berger hybrid at 2560 fps at 3,000 ft of elevation that means you can dial out to a mile before you run out of elevation. You can hold over 10 more mils for a total range of 2,000 yards. That's it, you're done unless you want to pick a spot somewhere up the mountain to hold on. And I've done that, it's a real PITA.

Now, lets say you were shooting the same rifle, but with a SFP scope like the SWFA 3-15x44. Well that's where things get interesting. You still dial up to a mile, but depending on your magnification you could hold over much much further. If the substentions are calibrated for 15x then they're five times as large at 3x. One mil of holdover becomes five. At 3x instead of 10 mils of holdover you've suddenly got 50 mils to work with.

Of course, you're now going from 15x to 3x magnification but surprisingly even at over a mile it's not that hard to pick up a three foot wide target at that magnification.

Just some food for thought for shooters that want to try their gear at longer ranges but can't afford premium FFP optics with tons of travel or don't shoot larger calibers like the 338's or 375's.
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Old 03-28-2017, 6:35 AM
Socalmp5 Socalmp5 is offline
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I went to the socal match and the winner had a $250 sfp scope with 140 moa of travel lol
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Old 03-28-2017, 10:33 AM
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First: I won't advocate anyone use 3 power during a 2k match.

I just want to point out that a good FFP scope should have graduations all the way to the bottom of the scope. If the field of view is the same; both SFP and FFP scopes will have the same hold over at the bottom of the scope.

IMG_0111.jpg

Cheers,

Last edited by focus; 03-28-2017 at 10:40 AM..
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Old 03-28-2017, 12:31 PM
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Quote:
Originally Posted by Socalmp5 View Post
I went to the socal match and the winner had a $250 sfp scope with 140 moa of travel lol
That's kind of amazing.

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Old 03-29-2017, 12:33 PM
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I think a FFP has its purposes and IMO, the PRS, FClass and Benchrest games do not really need them.

For one, most are not ranging with their scope. If you are ranging with the scope, then a FFP is needed. But, many of the matches are fixed distances.

Two, when trying to use the higher magnifications on a FPP scope, the crosshairs often cover tiny targets.

I agree with you on the SFP scope. My ballistic app (Strelok), actually has many of the crosshairs loaded on there. I can then dial a yardage and click on a button to show where my hold off is on the crosshair at a particular magnification for a SFP scope.
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Old 03-29-2017, 2:07 PM
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The problem with this method is the reticle calibration is lost and ELR is a situation where you need it the most. The magnification markings are nominal and not exact. 3 might be 2.5 or 3.37.

Even if they were exact, you don't have a method for lining them up with the required accuracy. If you used a test target and precisely measured range to calibrate the reticle at 2 different settings, you might be able to get it down into the 2.9 to 3.1 range, but it would take adding marks to the scope and then taking your time lining them up in the field. With a factory gun, you won't even be able to get it even that close with a tall target test. 30 mils up might be 29, or it might be 31.

It trades field of view for magnification and leaves you with a set of arbitrary marks that are only going to apply at the range you're currently shooting and until you adjust the magnification again. It's good to have a reference mark near what you're trying to hit, but not much more is accomplished.

It works better when you favor field of view for other reasons. Closer targets, hunting, or you're turning the magnification down to increase the image brightness. Picture milling an IPSC target at 500 yards. It's far enough that a correction is required, but not so far that the correction needs to be very accurate if all you want is to dump the target.

Forget developing ballistic solutions with data obtained using a scope this way.

It's at its best when sighter shots are allowed, but you're still hosed when you change magnification.
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Old 03-29-2017, 5:28 PM
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How about this way instead:

Say you need 74 MOA of elevation adjustment. In a SFP scope, dial as much on your scope as you can (let's say you bottom out around 50 MOA). If I have a reticle that has 5 MOA hash marks going all the way to 40 MOA, I would dial 44 MOA on the turret and then hold on the 30 MOA hash mark. This would effectively give me my 74 MOA of adjustment.
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Old 03-29-2017, 5:54 PM
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Quote:
Originally Posted by ShaunBrady View Post
The problem with this method is the reticle calibration is lost and ELR is a situation where you need it the most. The magnification markings are nominal and not exact. 3 might be 2.5 or 3.37.

Even if they were exact, you don't have a method for lining them up with the required accuracy. If you used a test target and precisely measured range to calibrate the reticle at 2 different settings, you might be able to get it down into the 2.9 to 3.1 range, but it would take adding marks to the scope and then taking your time lining them up in the field. With a factory gun, you won't even be able to get it even that close with a tall target test. 30 mils up might be 29, or it might be 31.

It trades field of view for magnification and leaves you with a set of arbitrary marks that are only going to apply at the range you're currently shooting and until you adjust the magnification again. It's good to have a reference mark near what you're trying to hit, but not much more is accomplished.

It works better when you favor field of view for other reasons. Closer targets, hunting, or you're turning the magnification down to increase the image brightness. Picture milling an IPSC target at 500 yards. It's far enough that a correction is required, but not so far that the correction needs to be very accurate if all you want is to dump the target.

Forget developing ballistic solutions with data obtained using a scope this way.

It's at its best when sighter shots are allowed, but you're still hosed when you change magnification.
Amen, finally someone that gets it. I got my head bit off saying the truth!

Go FFP if you can. I hardly dial my scope these days! It only sucks when you are powered down, then the reticle is too small for bad eyes like my dad's.

My wife thinks I only have 3 guns
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Old 03-29-2017, 5:58 PM
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Quote:
Originally Posted by ShaunBrady View Post
The problem with this method is the reticle calibration is lost and ELR is a situation where you need it the most. The magnification markings are nominal and not exact. 3 might be 2.5 or 3.37.

Even if they were exact, you don't have a method for lining them up with the required accuracy. If you used a test target and precisely measured range to calibrate the reticle at 2 different settings, you might be able to get it down into the 2.9 to 3.1 range, but it would take adding marks to the scope and then taking your time lining them up in the field. With a factory gun, you won't even be able to get it even that close with a tall target test. 30 mils up might be 29, or it might be 31.

It trades field of view for magnification and leaves you with a set of arbitrary marks that are only going to apply at the range you're currently shooting and until you adjust the magnification again. It's good to have a reference mark near what you're trying to hit, but not much more is accomplished.

It works better when you favor field of view for other reasons. Closer targets, hunting, or you're turning the magnification down to increase the image brightness. Picture milling an IPSC target at 500 yards. It's far enough that a correction is required, but not so far that the correction needs to be very accurate if all you want is to dump the target.

Forget developing ballistic solutions with data obtained using a scope this way.

It's at its best when sighter shots are allowed, but you're still hosed when you change magnification.
Very informative. Thanks.
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Old 03-30-2017, 4:05 AM
kcstott kcstott is offline
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I shoot my Mk 4 8.5-25X at 25X all the time. I have rarely dialed it back and i mean like twice out of 700+ rounds out of the rifle it's mounted to.

As for milling the 500 yard IPSC 100% target. well that's where knowing your holds comes in. Unless you are shooting PRS (Pretend we're Real Snipers) FFP is not needed in the civilian non LEO world. At least for me it's not. ShaunBrady statement of the lack of precision is dead on correct. And I'll add to it a bit. my scope says it's 25X but max listed at 25.1X so it all adds up in the math if you're trying to scale the reticle. minor error compound themselves though the calculation and get worse with range.

I find that hole idea a waste of energy and a exercise in frustration. from 100 meters to 600 meters I can shoot at full power and use my TMR lines to hold over. Now if you develop your loads properly. Stick with what you know shoots consistent out of your rifle and you have good real world dope you can just use the tick marks on the reticle to hold your shots if you are in a speed and distance shoot.
I'll give you a quick example. and i've worked this out with my rifle and i have field confirmation that my dope is correct and when i mean POI I don't mean i hit the 12" steel plate at X yards I mean I know where on the plate I hit at X yards. which is another thing..

On my rifle with my loads and at my 100 meter zero each half mill tick adds up to roughly a 50 meter step out to 700 meters and it's close enough for a hit on a 1 meter tall target. It's not X ring accurate but in a real world situation it would ruin a person's day if they were an enemy combatant. So the first half mil is 185 meters but round that off to 200 just to make the math and memory easier and add 50 for every half mil step thereafter until you run out out of reticle to use.

Now that's all well and good for short range. But this conversation said Long range and Extreme long range,

I've shot and connected at 1 mile both with a 300WM and a 308. my field of view at 1760 yards is near 25 meters wide i just can't see having to dial your scope back to get more hold over. i guess that's the "extreme" in long range. What i'm getting at is the farther you shoot the more your scope can see and the further you can hold over. if you need to dial down the power to get more elevation In my mind you are either shooting a high mag scope (reduced field of view) or shooting much farther then your equipment was set up for.
And FYI I'm not knocking what anyone does LR or ELR this is just how i do things.

Last edited by kcstott; 03-31-2017 at 3:24 AM..
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