SIGforum.com Main Page Mason's Rifle Room The Nightforce “Wedge Prism” for increasing elevation optically: What do the long range shooters think?
Main Page Mason's Rifle Room The Nightforce “Wedge Prism” for increasing elevation optically: What do the long range shooters think?Page 1 2
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| Freethinker |
I just got this notice from Mile High Shooting Accessories. It’s an optical device that’s mounted in front of the scopesight to effectively add ~50 minutes of angle to the elevation setting for extreme long distance targets. (It’s also available in a 100 MOA version.) I’m curious what the experts think of such a thing, and especially what effect it might have on the view through scopesights with very high quality glass. I’m also curious how it works optically if anyone can provide an explanation. https://www.milehighshooting.c...2742932e7f59c3967460 I seem to recall that another company already has a similar device on the market, but IIRC, it is a much more complex unit. (It’s not, BTW, something I’m thinking of acquiring myself because I would have no use whatsoever for it, so it’s not necessary to ask, “Why do you want something like that?” Asking a question does not imply an intent to buy.  )Added: I find that the Axeon company makes something similar, and for less than a tenth of the price of the Nightforce offering. Axeon has two versions, one that fits over the bell of the scope, and one like the NF that sits on a rail in front of the scope. I could find only one review of the Axeon that mentioned optical viewing quality and the device’s effect on precision—neither of which was very encouraging, at least not in the bell mount version. The reviewer said that the view was “blurrier,” and the one test group fired with the device alternating without was far larger than without. So, my question about the NF at a K-note still stands. It’s a far more impressive-looking device and the fact that each unit is evidently individually calibrated is encouraging, but there’s still the issue of whether it degrades the image quality of our super high definition glass, and whether it provides precise repeatability. ► 6.4/93.6 ___________ “We are Americans …. Together we have resisted the trap of appeasement, cynicism, and isolation that gives temptation to tyrants.” — George H. W. Bush | ||
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| Member |
A grand for what looks like a lens protector? They can keep it | |||
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| Freethinker |
It's not, and I was seeking responses from people who know it's not. ► 6.4/93.6 ___________ “We are Americans …. Together we have resisted the trap of appeasement, cynicism, and isolation that gives temptation to tyrants.” — George H. W. Bush | |||
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| Member |
I know what it is. I have no experience specifically. But I would say that if I'm out of elevation as a principle I'm doing something to fix it that isn't optical but physical like more rail or more scope. Adding more in the optical path seems totally counter intuitive when you have this specific issue . “So in war, the way is to avoid what is strong, and strike at what is weak.” | |||
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| Freethinker |
We must admit, though, that physically adding 100 or even 50 MOA to an existing setup might be difficult. I’ve seen pictures of scope mounts that place them several inches (a foot?) above the receiver because merely increasing the angle between the scope and bore gets to the point that the barrel blocks the view of the target. The other company I was thinking about that produces high quality optical devices for raising the effective elevation of the sight is tacomHQ. If I read their descriptions correctly, they can raise the effective elevation of a conventional sight by as much as 600 MOA, and that seems to me to be in that foot-high scope mount range. Surprisingly (to me, anyway), the prices of many of their devices aren’t any more than what the new Nightforce devices’ are, and the NF offerings are simple optical prisms (as I understand them). In fact, there must be some reason why the company believes they can get more than 10 times as much money for them as the similar Axeon devices. Hence my question about the type of device in general. ► 6.4/93.6 ___________ “We are Americans …. Together we have resisted the trap of appeasement, cynicism, and isolation that gives temptation to tyrants.” — George H. W. Bush | |||
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| Member |
On a scale of 1 - 10.... This is a NOPE!! covered in NOPE sauce. Essentially, you want to take a "precision instrument" with verified scales and adjustment that are mated with tolerances to ensure there is linear or scaled movement; then corrupt that system with a device that is "mounted" in some manner to optically change it's function. Pass. Long range shooting is a science of arc or degree measurements that have increasing values of error as the distance increases. So what is 1/4" of error at 100yds becomes 150ft at 2000yds. Validated, reproducible, error free results don't come in a package that "mounts" to an exisiting precision device. Andrew Duty is the sublimest word in the English Language - Gen Robert E Lee. | |||
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| Member |
FFS nobody, and I do mean nobody, goes to the range and decides, you know what, I need another 50MOA because instead of shooting 300 yards, I plan to shoot 1400 yards. I have no idea who shit this idea out, but precision options are precision because they are done in a precise setting, and sealed to keep shmutz off the lens, not slapped on in front of another scope on a whim because jimbob wants to see how far his ar can shoot. For $100 you can get a 20, 30 or 40 MOA scope rail to get you how far you need to go. For $300, you can get a good scope mount with an extra elevation added. If you want to shoot at extreme distances, buy the gear you need, and show up ready. I honestly can't believe this is even a thing, I mean every element you add after the objective degrades quality, especially if it is not sealed off. | |||
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| Member |
From those of us who have actually shot out to 2,000 yards: - the first sentence is generally correct - the second sentence is grossly overstated | |||
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Member |
I run 20 MOA rails on both my precision rigs. That will usually give me enough MOA, but wouldn't putting a 30 MOA rail do essentially the same? It's an honest question, not bashing the wedge as I know zero about it. | |||
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| Member |
The website says it is 50MOA and 100MOA. I think you meant to say "adding a 30MOA scope mount to a 20 MOA rail", in which case yes, the combined amount would be 50MOA at the SCOPE. | |||
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| Member |
I agree... i added the excessive value for reinforcement of the concept for those that haven't actually gone to extreme distances. The concept was what I was trying to achieve. Andrew Duty is the sublimest word in the English Language - Gen Robert E Lee. | |||
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| Member |
Duty is the sublimest word in the English Language - Gen Robert E Lee. | |||
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| Member |
I'm not an optical engineer, but my guess is that the lens (wedge prism) is canted slightly, thereby changing the slope of light entering the objective, and there for making the shooter aim higher to get the trajectory. Only problem is that is it based on the mount, and being in front of the scope, meaning the distance between the objective and wedge would need to be specific to align the light and get the correct MOA. In theory, it would either a) cut down on the light transmitted (due to optical element and the size, or b) make the outer rim of your scope view fuzzy. The reason I think this is a piss poor decision, that should have been released on April 1, so when people start to question in, they could have said it was an April fools joke, is that slightest change in how it locks into the picitinny rail could change the point of aim. | |||
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| Member |
For those who do not have experience with shooting at ELR targets, it is better to give realistic examples instead of grossly exaggerated figures. 1/4 MOA error at 2,000 yards is roughly 5 inches. 150 feet (1800 inches) of error at 2,000 yards is roughly 88 MOA. Such a comparison doesn't help inexperienced ELR shooters. A better concept would be to state that if an ELR rifle/ammo/shooter system is capable of 1/4" (1/4 MOA) accuracy at 100 yards, the ELR system may deteriorate to a 1-2 MOA capable (roughly 20 to 40 inches) at 2,000 yards -- in calm conditions. Wind at distance is a whole different ballgame. | |||
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| Freethinker |
Thanks for the comments thus far. Most of that is what I was (vaguely) thinking myself, but I try to avoid the temptation to answer my own questions when there are experienced authorities on the subject of things like extreme distance shooting and optics. One thing I should point out about the prism units made by Axeon and tacomHQ, though, is that both seem to be envisioned by the companies to be used not for extremely long distance shooting but rather for the much more modest purpose of effectively changing relatively short zero distances quickly and without modifying the sight in any way. For example, if using an Axeon device, flipping it up and down changes the zero from 100 yards to 330 or 530 yards, and then back to 100 yards (the load for that is not specified, however). I plugged some figures into the Applied Ballistics solver, and just as an example using the 308 Winchester Federal 168 grain Gold Medal Match load, the change in zero from 100 to 500 yards requires only about 13 MOA difference, and to 300 yards ~5 MOA. Those figures are obviously far less than the 50 or 100 MOA differences of the Nightforce devices. And another significant difference between using an optical device to change the sighting elevation and purely mechanical methods like elevation rails or mounts is that the mechanical methods are fixed. If we’ve added 50 MOA with a rail and scope mount, what do we do if we want to shoot back at 100 yards? Again, none of this is to imply that I’m going to spend $1K or more so I can hit those 1800 yard targets with my 308 Tikka. And if I need to hit targets at 300 or 500 yards with a rifle and sight zeroed at 100, I do know how to do that. But I am always curious about the new things I learn about shooting, and I appreciate others’ opinions and insights. ► 6.4/93.6 ___________ “We are Americans …. Together we have resisted the trap of appeasement, cynicism, and isolation that gives temptation to tyrants.” — George H. W. Bush | |||
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| Member |
That's where your own dope would come in to play. Same as having a 200 zero and using a scope with a Zero stop. | |||
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| Freethinker |
Okay, I think I understand what you’re saying and understand how someone could do that (unless he was zeroed at +50 MOA and had a zero stop), but it would be far from ideal and would be very unlikely to use a center of the crosshairs hold—which is the whole idea behind at least a couple of these devices. Thanks, though, for the concept. And, oh: That’s one of the reasons I don’t have 200 yard zeroes, and especially not with zero stops.  ► 6.4/93.6 ___________ “We are Americans …. Together we have resisted the trap of appeasement, cynicism, and isolation that gives temptation to tyrants.” — George H. W. Bush | |||
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| Member |
Same here. I'm not smart enough to remember where my low hold would be. | |||
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| Member |
I shoot ELR, 1 mile and out, on a fairly regular basis so maybe I can help shed some light on this topic. These systems have been around for a while with the Charlie TARAC from tacomHQ leading the way for most guys that are serious ELR competitors. First, let's address internal scope travel. Every scope has a limited amount of OVERALL travel for the reticle. Let's say your scope has 100 MOA of internal travel and you are zeroing at 100 yards and have mounted a 0 MOA scope base. This configuration will allow you approximately 50 MOA of DOWN travel and 50 MOA of UP travel. If wanting to shoot at a distance that requires you dial 60 MOA elevation and you want to hold the center of your reticle on the target, you will not be able to do it. If, however, you use a 20 MOA scope base, you will "rob from the down and give to the up", meaning you will now have 30 MOA of DOWN travel and 70 MOA of UP travel, enough to dial and hold center reticle on your target at the longer distance. This scenario becomes more complicated when shooting BEYOND the available travel of your scope AND the elevation/cant of your scope base. Your options are to get a scope base with more cant so that your turret is bottomed out and you can still obtain a 100 yard zero or forego the 100 yard zero and get more cant than 50% of your scope's travel and zero at a longer yardage; it all depends on the distances you will shoot. This leads into the issues that arise with more elevation/cant in the scope base. By increasing the cant, the higher your scope's ocular will rise and the lower your objective will fall. This means having rings with enough height to handle the objective's fall and a cheek riser that will handle the ocular rise. And herein lies the purpose of the MOA/MIL shift type of prism. If set up properly, you can set your scope to zero, let's say 100 yards, and knowing the total internal travel you have available, get an optic enhancer that will take over from the most your scope will travel up in elevation an additional amount, in essence usually DOUBLING your scope's travel and allowing you to hold your reticle center on a target at long yardages. As an example, I sometimes run a Vortex Gen 2 Razor that has 28.5 MILS of internal travel. This means I have 14.25 MILs up and 14.5 MILs down. I shoot with a 50 MOA base (this equates to about 14.5 MIL) which puts me at the BOTTOM of my turret but allows me to zero at 100 yards and have my full 28.5 MILs of dialed UP elevation. This configuration lets me shoot to 2425 yards with the reticle centered on the target. If using the 100 MOA "Wedge Prism", I would dial back to zero on the scope and immediately have 29.1 Mil of elevation thus increasing my usable travel of the scope to 28.5 MIL + 29.1 MIL for a total of 57.6 MIL. This means that I could, with a caliber capable of going the distance, shoot 3325 yards without holding AND without changing my cheek rest or position behind the rifle. I know a few shooters who have 3 of the TARACs, one in 30 MIL, one in 60 MIL and yet another in 90 MIL. Using the rifle I listed above, this means that without a TARAC, my travel is 28.5 MILs. With the 30 MIL TARAC my travel increases to 58.5 MIL, with the 60 MIL TARAC my travel increases to 88.5 MIL and finally with the 90 MIL TARAC, I get 118.5 MILs of up elevation. While this sounds like a lot, it's only enough to get me to 4600 yards which is 2.6 miles (which is beyond the capabilities of this particular rifle/caliber). Changing rifles and calibers to one that is more capable of shooting 2-3 miles would be a help and using the same scope and TARACs, would have the ability to shoot beyond 5000 yards. Hope this helps...Semper Fi ____________________________________________________________ Money may not buy happiness...but it will certainly buy a better brand of misery A man should acknowledge his losses just as gracefully as he celebrates his victories Remember, in politics it's not who you know...it's what you know about who you know | |||
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| Freethinker |
Thanks for that discussion. I understood the theory, but examples, and especially what people are using are most useful. The TARAC is obviously usable if long range shooters are buying it for the purpose, so that answers that question. I’m still curious, though, about something with a prism rather than mirrors that the TARAC uses. Given the Nightforce prices and the general reputation of the company, I assume that they are decent products, but it would be interesting to know. What would the user of a scope with super high quality glass think about inserting another lens as a separate component mounted outside the scope in line with the optical path? ► 6.4/93.6 ___________ “We are Americans …. Together we have resisted the trap of appeasement, cynicism, and isolation that gives temptation to tyrants.” — George H. W. Bush | |||
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SIGforum.com Main Page Mason's Rifle Room The Nightforce “Wedge Prism” for increasing elevation optically: What do the long range shooters think?
Main Page Mason's Rifle Room The Nightforce “Wedge Prism” for increasing elevation optically: What do the long range shooters think?© SIGforum 2024