NP-2DD Reticle in F class

[dieselten]

IMO NF could take the bottom dot and get rid of it

I never use it, but it seems some find it usefull!

My book says it's 4 MOA @ 22 power....which is the Range Finding Setting.

Taildrag, at what yardage?

I also did some searching as the NF web site doesn't offer the same info there any longer but found it here:

http://www.longrangesupply.com/index.php?main_page=index&cPath=1_35

If you scroll down to the NP-2DD this is the same as what my booklet states:

A secondary .125 M.O.A. diameter dot is located 4 M.O.A. below center at 22x. This dot is a 500-600 yard holdover point for most flat shooting cartridges. This simple and effective reticle performs in long-range situations while maintaining quick target acquisition capability for short distances.

That web site is wrong. You can download a reticle map directly from Nightforce. At 22x the lower dot is 8 moa, at 11x it is 16 moa, and at 42x it is just barely over 4 moa. Another problem is that the power ring on Nightforce Bench Rest scopes is rarely (if ever) accurate. I mapped my reticle to both a grid target at 100 lasered yards and to a collimator map to confirm, and the power ring was off by a significant amount. After confirming power ring location for each setting I used a silver sharpie to put reference marks on the ring. Also, the gaps around the center dot are great for wind holds, just keep track of the exact gap size and use the sharpie marks for reference.

 

[DennisH]

Just to make sure and put my mind at ease:

30X at 600yds, the bottom dot equals how many MOA's?

And, again at 30X-600yds, 1 MOA = (how many inches on the target) ? Top dot

If there is a formula, please let me know.

Thanks, Dennis

 

[XTR]

I use the reticle for F-TR and love it. According to the manual that came with my 32BR the distance from the center dot to the lower dot is 12.6 MOA@ 15x, 8 MOA a@ 22x, 5.7 MOA @ 32x or 4.3 MOA @42x


It is designed to be used as 8 MOA at 22x in their SFP scopes, the sales literature claims it to be "the 500-600yd holdover for most flat shooting cartridges." I have no idea what that actually means. If I loaded my 7mmRM with 162 A-max's and pushed them 3000fps it would be about right for a 500 yard hold.


Yes there is a formula, this is a SFP reticle so the reticle subtension changes linearly with magnification so 12.6 MOA @ 15x will be 6.3 MOA @ 30x. Distance is irrelevant because MOA is an angular measurement.

I'd never buy this reticle to do hunting holdovers. For that I'd either get a SFP that had a good grid at max power (like my Swaro BRX) or I'd get a FFP scope.

 

[Forum Boss]

Bob...there is nothing wrong with your idea to use the NP-2DD "over and under dots" as you state! Try it, and if it works for you, fine. However, like the other responders to your question, I would not bother to use it; rather, just click up/down the elevation going from 600 to 1,000 yards.

There is one exception though where I regularly use the lower dot! That is for 1,200 yard shooting...a fad at the Midwest Palma Championships held annually up at Lodi, WI. Here I fully employ your idea. Following the 1,000 yard match, I click up 2-3 minutes of elevation depending on the load being used for my 7mm RSAUM, go to 42 power, and use the "lower" dot. For me, the lower (and smaller diameter dot) at 42 power provides a pref errable aiming dot for the much diminished size/appearance of the 1,000 yard target face (conditions permitting). In this instance, I'm really not too lazy to just "click up", I'm after "uncovering" the 10/X rings as much as possible as they are obscured by the larger upper dot, by using the smaller aiming dot, and to more better hold on on the rings horizontally for windage purposes.

Danny Biggs

[br]
What could this newbie Biggs guy know? He only has one post!

Sharp eye, Steve. For those who did not understand the irony in Steve's post -- Danny Biggs is one of America's very finest F-Class shooters. He has won major titles in both F-TR and F-Open. Here's Danny in Sacramento:

 

[DennisH]

Still wondering, shooting my 308 . . . .

And, again at 30X-600yds, 1 MOA = (how many inches does this equal on the target) ? Top dot

 

[Steve Blair]

Sharp eye, Steve. For those who did not understand the irony in Steve's post -- Danny Biggs is one of America's very finest F-Class shooters. He has won major titles in both F-TR and F-Open. Here's Danny in Sacramento:

[br]
Absolutely right, Paul. Danny is a fine shooter from whom I've learned valuable lessons just by watching. At the Berger Nationals this year, Danny had (for him) a bad day on Sunday and still beat me. Not that beating me is much of an accomplishment but his scores are still good when he's shooting off his usual pace.

 

[XTR]

Just to make sure and put my mind at ease:

30X at 600yds, the bottom dot equals how many MOA's?

And, again at 30X-600yds, 1 MOA = (how many inches on the target) ? Top dot

If there is a formula, please let me know.

Thanks, Dennis

It is pretty obvious here that the basic concept of a minute of angle and the effect of magnification has evaded a few people. It is geometry folks.

One (1) MOA = 1/60 of a degree, there are 360 degrees in a circle.

This is a 2FP scope, so the magnification causes a linear change in the distances subtended by the reticle.

As stated earlier, according to the manual that came with my 32BR the distance from the center dot to the lower dot is 12.6 MOA@ 15x,
8 MOA a@ 22x,
5.7 MOA @ 32x or
4.3 MOA @42x

So do the math, 12.6÷2=6.3 MOA from the top dot to the lower at 30x

Note: If you wanted 28X you'd take 12.6÷(28÷15)= 6.75 MOA at 28x (That part is Algebra 1)

Now to determine the distance subtended by the arc of 6.3MOA you do a little geometry.

There is a basic number used in shooting that 1 MOA = 1 inch at 100 yards, and it's close, but not quite, the MOA is an angular measurement of an arc and not a straight line, at 100 yards it doesn't make much difference but at longer distances it gets a little off.

The actual distance is determined by taking the circumference of the circle whos radius is defined as your shooting distance and dividing it by 21600 (360 degrees * 60 min/degree)

So for a circle of 100 yards 1 MOA = 2Ï€r/21600 = {2*3.14159*(100*3*12)}/21600 = 1.047 inches at 100 yards

For 600 yards its 6 * 1.047 = 6.28 inches per MOA

So if the reticle subtends 6.3 MOA at 30X the distance between the dots at 30X is:


6.28" @ 100
12.56@ 200
18.84 @300
25.73@400
31.41@500
37.70@600


Do you get it now?

To make this even more confusing there are some scopes (Not too many) that the turrets and the reticles are calibrated in IPHY or "Inches Per Hundred Yards"

Next we can have a discussion about mils and mils vs MOA, but before we do that I'd suggest a trip over to Snipers Hide and a quick search in the Optics forum.

 

[DennisH]

So for a circle of 100 yards 1 MOA = 2Ï€r/21600 = {2*3.14159*(100*3*12)}/21600 = 1.047 inches at 100 yards

For 600 yards its 6 * 1.047 = 6.28 inches per MOA

So if the reticle subtends 6.3 MOA at 30X the distance between the dots at 30X is:


6.28" @ 100
12.56@ 200
18.84 @300
25.73@400
31.41@500
37.70@600


Do you get it now?

To make this even more confusing there are some scopes (Not too many) that the turrets and the reticles are calibrated in IPHY or "Inches Per Hundred Yards"

Next we can have a discussion about mils and mils vs MOA, but before we do that I'd suggest a trip over to Snipers Hide and a quick search in the Optics forum.

XTR, this is exactly the information I am looking for! THANKS . . . If I were a little bit more of a math wizard, I am sure I would have come up the the same answer as you did! At 30 power, 6" per MOA was perfect.

Now I know why my correction calculations go to &^%#* when I change to 22 power when the mirage is heavy! I will have to calculate this . . . . . as soon as I figure out your formulas

Thanks again, Dennis

 

[DennisH]

@ XTR,

Using your calculations, @ 22 Power, 600 yds, 1 MOA should equal 8.318182 inches on paper.

12.2/(22/15)=8.318182

I took business math : , geometry and Algebra II didn't go over to well!

Dennis

 

[XTR]

The problem with 2FP scopes is getting the actual power as opposed to the power marked on the ring, which may or may not even be close.

What you're trying to do is the reason that First Focal Plane scopes are the norm in "tactical" shooting. The reticle subtensions don't change with magnification, the reticle gets bigger with the image, the problem with them for target shooting is that the reticle usually gets to big that t blots out the aiming point for target shooting.

 

[boa454]

i have the NP-2DD on my 22-250ai and i use the centre dot for my 200m zero and the bottom is near spot on for a 600m zero....thats what works for me on our range anyway

 

[highlife]

http://bulletin.accurateshooter.com/2012/04/np-2dd-tip-from-danny-biggs/

 

[DennisH]

@ boa454

i have the NP-2DD on my 22-250ai and i use the centre dot for my 200m zero and the bottom is near spot on for a 600m zero....thats what works for me on our range anyway

What power setting are you using?

 

[boa454]

I generally leave it on 14x that's using Sierra 52gn HPBT @ 3800 fps