First Focal Plane Vs. Second Focal Plane

[barnesuser28]

I gave you one but I will elaborate.

A 8~32 NXS has 65 total moa of internal elevation. You mount it with a common 20 moa rail. This gives you 50 +/- moa of elevation dial up. Your reticle on full power is 20 moa for a total of only 70 moa. There is a rock ledge at 2100 yards with a visible dark spot that is screaming at you "come on, try me" your 338 LM with a 300 Berger needs 81 moa. You are short by 11 moa. But you have the option to dial back to 16x and now you have a total available moa up of 90 moa.

Not common, but yes it is a fact and I have been it that position before.

Jeff

That is the exact reason i chose the vortex 6-24 pst SFP, it has 65 MOA in adjustment and 10 in the reticle at 24x, if i back it off to 12x i have 20, 8x 30, and 6x at 40. The magnification ring has those spots marked on it and you turn it and you can feel a distinctive little stop where you need to be. My 284 win with the 162 A-Max will need about 75 MOA up at 1800 yards, so i will back it off to 12x and dial 55 MOA and use the bottom hash mark as a hold.

Riley

 

[orkan]

I encourage you to test that extensively when your scope arrives.

Most optics actual magnification does not precisely match the indications printed on the ring. Some not even close. So you must "calibrate" the magnification ring to the reticle. Here's an article that describes the process. (one method anyway)

How to Optically Check a Rifle Scope

Last time I did this test, we did it on a nightforce, leupold, vortex, bushnell, and a few other scopes. NONE lined up where they said they would be. Even those that did, the numbers had no "tick" marks to line up perfectly. As Broz pointed out, nightforce has a little "tick" line that lines up with their indicator at half power. Yet I would be very surprised if those are dead on either. The one we tested wasn't.

The best way to do it is to calibrate it, and put precise markings with little needle scratches. Then, if you confirm them to be correct, engrave them. Once it's calibrated, it's set for good. (provided the optic is quality and the reticle isn't moving around inside the erector)

EDIT: See this is what I'm talking about. Why wouldn't they design that reticle so that the holds continue down the entire stadia? Why stop it at 10 moa and go to a big thick black line? They could give you a lot more holds in that FFP to equal the holds you'd have available in the SFP if they just built the reticle differently.

 

[Pdvdh]

Yup. It's a lot simpler for a manufacturer to put a mark on a magnification ring than to calibrate it to ensure the mark is at the exactly correct location. Same with turret adjustment values. They ought to be tested before they're accepted as correctly advertised.

 

[barnesuser28]

I encourage you to test that extensively when your scope arrives.

Most optics actual magnification does not precisely match the indications printed on the ring. Some not even close. So you must "calibrate" the magnification ring to the reticle. Here's an article that describes the process.

How to Optically Check a Rifle Scope

Last time I did this test, we did it on a nightforce, leupold, vortex, bushnell, and a few other scopes. NONE lined up where they said they would be. Even those that did, the numbers had no "tick" marks to line up perfectly. As Broz pointed out, nightforce has a little "tick" line that lines up with their indicator at half power. Yet I would be very surprised if those are dead on either. The one we tested wasn't.

I have the scope already but havent tested it, i just took it out and saw an eagle WWAYY out there. I checked to see if i could quarter it, i could at 24x, then went on google earth and found the approx range, 3975 yards and i could quarter the eagle without much trouble. There is also a rock that is 1/4 moa high and 1/2 moa wide at 4,000 even and i could quarter it. The reticle i have is .06" at 100 yards.


Riley

 

[barnesuser28]

Yup. It's a lot simpler for a manufacturer to put a mark on a magnification ring than to calibrate it to ensure the mark is at the exactly correct location. Same with turret adjustment values. They ought to be tested before they're accepted as correctly advertised.

And i do do that, i got the scope for christmas and i havent had a chance to test it yet.

 

[Franklin]

Aaaah. I'm tracking now. I thought we were talking specifically about long range hunting, not just launching rounds at rocks for fun. I'm tracking, and agree, with that kit you would do just as you said.

However, with my Premier FFP, I'd simply back down the magnification a bit, and use my reticle for the hold. I have 65 mils (227 MOA) of holds available at 5x. An additional 28 mils available in my turret, for a total of 93 mils (325 MOA). Forgive the poor picture quality, but in the image below, you can see the hash marks every 5 mils along the entire vertical stadia, as well as windage stadia. If I dial .5 mils left, or right, I can use the tip of that stadia for a precise aim point.

Other FFP reticles have similar functionality.

Why would you need to back the magnification down on a ffp scope to acheive this????

 

[orkan]

Why would you need to back the magnification down on a ffp scope to acheive this????

Because at 25x it looks like the image below. Not as much FOV, and not as much reticle seen.

 

[rick523]

I have read every post,interesting. I will stick with both of my sfp nxs' The more important question on the table is, do we have to put in for a draw to attend this shooting match in Sept. or can we just show up? I will be in Wy. and would be willing to make the trip North.

 

[Pdvdh]

The more important question on the table is, do we have to put in for a draw to attend this shooting match in Sept. or can we just show up? I will be in Wy. and would be willing to make the trip North.

Shooting match? You mean shooting 'Duel'! Walk ten paces, turn around, point, shoot. gun) The guy that can only count to two always wins...

It's actually been a pretty healthy and interesting dialog. Many good points covered and debated - pros and cons.

 

[ishootkittens]

Hell, Im willing to take the trip from Virginia!!!

Thanks for explaining this to me guys. I really appreciate all the info!

 

[Tnwhip]

I have been watching this post because I just ordered a Viper 6x24 ffp. It will arrive tomorrow. It will be my first FFP scope. I have studied this subject for a year now I may not need the FFP but I have had several times hunting that I wish I had FFP. Now I will find out if it is worth the extra money. I hunt in the South over Bean fields. After a year or two of hunting with it I will know what I like, FFP or SFP. Sometimes you just have to see for yourself.

 

[orkan]

Sometimes you just have to see for yourself.

Truer words never spoken!

Yet that will mainly only tell you about that singular optic. Can't judge all FFP from looking at a single unit anymore than you can judge anything by a single unit. If that one doesn't work out for you, give me a call and I'll gladly help you find one that does.

 

[sp6x6]

I shoot a ffp. I picked a mark 4 TMR,small space at center of cross hair.Bought for the lighter weight on my packer.Not nearly the cost of the top end stuff.I love the scope.works great for my style.I hike dark timber all the time,year before last shot 6x6 with alder obscuring at 50 yrd.That is why I pack 338 for last 30 yrs.The cross hairs are thick to thin.Lets see my best year I harvested 26 animals.One was a B&C 51'' MT moose,passed 18 bulls, 330 6x6 at 680 yrds. And a 160 whitey at 34 paces.My last 15 elk,6x6gun).I really dont care what I have in my hand,LR, took the 30-30 out some elk hunting this season or bow.I just want to be out.Scope is like Ford,Dodge,Chevy.Pick what you like.

 

[aroshtr]

After all this discussion I now realize so many benefits of both designs, that I know I will be first in line when someone comes out with a durable 20-25x DualFP scope with 80-100 minutes of internal adjustments (as long as it is at a reasonable price point).

The only DFP scope I could find was a US Optics that was in 1-4x configuration.

Hopefully Vortex, Leupold, Nightforce, etc... are listening, and can see there would be a market for something like this.