Sig BDX Scope Review

[catorres1]

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The BDX system is precipitated on several concepts. Speed, connectivity, integration, flexibility, choice. All of these are achieved through the application of technology. For some shooters, this is something they don’t want. Others are comfortable with some, but not all, of what the system offers. And others see the entire system as a logical and welcome advance.

Regardless of where an individual stands, the BDX system is designed to allow each shooter to choose just how much tech they want in their kit, and select the appropriate components accordingly. It’s not an all or nothing system, it’s a system of options where the shooter gets to make their own decision on how they want to hunt and what role they want tech to play. With that in mind, the following covers how far you can go in integrating the entire solution by utilizing a BDX scope, if that is what you want. That may not be appropriate to everyone’s mind (indeed, the integrated scope/RF system cannot be used in Idaho or Oregon at this time, but according to Sig, is legal in every other state, including Colorado). But the following hopes to let you know what your options are so each individual can decide how far they want to take it.

As I mentioned in my review of the 2400, both the 2400 and 3000 BDX’s can connect and work in tandem with the phone app, a Kestrel, or a Foretrex 701 to provide shooters with a flexible ballistic solution that fits their needs. When connecting to the Kestrel or Foretrex, we have access to a system that provides shooters an accurate solution for as far as you can range, limited only by the subtension limit of the scope’s reticle.

But though I will be speaking to the 2400 and the 3k integration, the scopes will also connect with the lower line of BDX RF’s like the 2200, you just can’t connect to a Kestrel or Foretrex, so your ballistic solution is limited to 800 yards. If a BDX scope is utilized, the data flow communication is complete going from rangefinder, to ballistic solver, to BDX scope, where the holds are indicated via illuminated dot automatically.

Basically, when the RF and the scope are paired, the scope will illuminate one dot on the vertical stadia, showing where to hold for elevation based on the calculated ballistic solution from the RF or Kestrel. It will also illuminate another dot on the horizontal stadia, showing how much to hold off for wind based on the same solution. For the wind, you can set it to show a dot on both sides so it is direction agnostic, or it can be set to show based on the wind direction communicated to it by the RF/Kestrel.

Hold points move proportionally based on magnification as well, so that no matter what power you are dialed to or change to (even after the solution is communicated), the holdover/wind distance is always proportional. Sig calls this their digital focal plane because, while the reticle is in the second focal plane, by utilizing automatically adjusting hold dots, BDX scopes act a bit like a FFP scope in that subtension values remain the same, no matter the magnification.

The BDX scopes can also be used with benefits without a BDX rangefinder. By connecting the scope to the app, you can upload one of up to 25 custom curves that you create into the scope. Using the curve, 8 hold points can be custom designated by the shooter to match their load or their needs. In setting this up, the shooter has two main choices. The first is by range. In this case, you designate the range you want each dot to be set for, then the app calculates the drop based on your curve and the environmentals and turns on the appropriate dots to correspond to the needed holds for those ranges. So you could have dots for 300, 350, 400, 500, 550…up to eight choices in whatever increments you want, with the maximum range being 800 yards. The maximum number of hold points is 8, but you can have as few as you like.

This method really makes sense for hunters that need a fast but flexible solution. All you need to do is get an angle modified range from your RF (whatever brand), then hold on the appropriate dot and send it, just like other BDC scopes. The big difference is that since the dots are not static, they will work no matter what or how conditions change. Whether it’s magnification, environmentals, a new load…your holds can be updated. While not quite as fast as the full BDX system, it does allow you to work with data from whatever RF you choose to use, and does not rely on Bluetooth for its function once it has been initially setup. It makes distance based BDC holds work much more effectively and flexibly.

The other choice for holds is simple MOA , and despite the dials being MOA only, Mils. Again, the shooter can go into the app, set it to Mils or MOA, and then designate the distance between hold dots. So, for example, you can set each dot to be 2 MOA apart, or maybe you want 2 MOA for the first 4, then 1 MOA for those following. Whatever you decide, you have up to 8 dots that you can designate. I personally find this system less useful for general use, but it could be useful when shooting beyond the range of how far the scope can dial, at least if you are working in MOA. Theoretically, you could max your dial elevation out, and then utilize MOA dots to get the additional holdover you need to make the shot.

Sig 4.5-14x44 BDX scope, Sig 3000 BDX RF Binos, and a Kestrel, together provide a fast solution in the field
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To summarize Sig’s digital focal plane and the ballistic reticle options, the points adjust based on magnification and, of course, can be changed as necessary, and each one can be individually designated and turned on and off. So conceivably, you could set your scope up one day with MOA or Mil dots at whatever increment you want. The next day, you could have holdovers for specific distances for that particular rifle and load. And all would automatically adjust according to the loaded curve and environmentals (for distance based holds), as well as the magnification setting of the moment.

BDX scopes also have an integrated digital cant indicator in the viewfinder. When the scope senses that it is off cant, a dot on the far edges of the horizontal stadia will blink, indicating that the rifle needs to be leveled upwards on that side. The cant indicator can be configured by the user with various settings as to the level of sensitivity where it will be activated, including an automatic mode that adjusts sensitivity based on the distance of the shot (not available when using MOA or distance holdover mode). Obviously, off is an option as well.

Sig has also included an interesting way of communicating to shooters when a shot is outside a defined envelope of lethality. Called Kinethic, it uses ballistic data to indicate to the shooter via a blinking dot that their shot may be too long for an ethical kill. That threshold is set by the shooter at whatever threshold they want, using either energy or velocity as the determining data point, and automatically updates based on the environmental conditions. So, for example, at sea level you may be good for a 700 yard shot by your standards, but that might increase to 900 yards as you increase elevation etc. Whatever you set it to, Kinethic adjusts and keeps track to let you know when the range it has received falls below the limit you have set. Like everything on this scope, this can be turned entirely off as well.

This review would likely turn into a book were I to go through all the features in exhaustive detail. but suffice it to say, there is a reason why Sig chose to call their optics division ‘Electro Optics’, and the BDX scope is an example of their focus on using technology, integrated into their optics, to push the boundaries of their products’ performance and capabilities. But what also keeps popping up the more I use the scope and system is it’s really also about options. Indeed, everything that the system offers can be turned off and disabled, and the scope is backed up by smart power management options as well as ‘no power’ options, so you are never left entirely depending on the tech.

 

[catorres1]

Sig BDX Scope Review Continued

Optics

At this time, the scopes in the BDX line are variants of the Sierra 3 scopes. The scope I had for testing was their 4.5-14 x44, which as a 30mm tube. They also have a 3.5 -10 as well as a 6-18 in the line, but I requested the 4.5-14 as a good middle of the road range for hunting and some longer range shooting.

The scope is much the same as their Sierra 3 scopes, so it shares the basic characteristics. All the BDX scopes are MOA at this time, though future scopes might have a Mil option, I don’t know. Clicks are the standard .25 MOA, and the turrets on this model are covered, but have regular finger adjustable dials underneath that can be reset to zero, but there is no zero stop. This model has the parallax adjustment on the left side where the power dial is for the BDX system, and BDX scopes are IPX-7 rated.

Parallax adjustment is on the left turret, along with the power selector for the illuminated reticle/BDX system. Elevation and windage dials are capped​

I was pleasantly surprised when first using the scope, the glass was clear with good color balance, lacking the blue color hue that the RF exhibits. There are thin lines that traverse the bottom half of the scope, ostensibly to enable the hold dots on the stadia, but they are barely visible and disappear once you get used to them.

To test the scope’s brightness and clarity, I set it up along with a Zeiss HD5 3-15x42, and a VX6 3-18x50. All three scopes were set to 14 power and were parallax focused on a standard eye chart at 100 yards. We began testing on an overcast day 30 minutes before sunset and ran through to 30 minutes after sunset, and I brought my teenaged son with me as a second set of much-superior eyes to get his opinion as well. As has pretty much always been the case, his recorded observations about what he could see verses what I could see through a given optic was about 1 line deeper on an eye chart, but our rankings of the scopes in order of performance were consistent.

Overall, we both scored the VX6 as the sharpest and clearest, being able to read deeper at any given light level than the other two under all light conditions. Next, surprisingly to me, was the Sig. And just behind was the HD5. The VX6 held a solid 1-1.5 line advantage over the Sig from 30 minutes before to 30 minutes after sunset. The Sig, on the other hand, held a much smaller, but consistent advantage over the HD5. Generally, about a half a line advantage (ie, could read half the letters but not all). This stayed pretty consistent through to the end of shooting light. Bringing up the rear, but not by much, was the HD5. Not that it was poor, I have used this scope hunting hogs into the night enough to know that I could easily take shots past shooting light with this scope, so its performance is more than enough to get you to shooting light for most game animals. But the fact that the Sig exceeded it, though marginally, was unexpected considering the price point of the base (non-BDX) Sierra scope. I would be very interested in seeing some of Sig’s top end glass, like a Tango 6, to see how it does in comparison. But as it is, we did not see any indications that the current BDX Sig won’t get the job done to past shooting light.

One other point about the optics that should be considered is around flare and haze control. I have been in several situations with other scopes where, due to internal design and/or the coatings, stray light becomes a significant problem depending on your angle to the sun. This is particularly evident at the end of the day when the sun is low on the horizon. What can result is very strong veiling flare, such that you cannot actually see through the scope without dialing mag down significantly. The scope my son had originally had such terrible veiling flare that the guide we were with thought it was broken and suggested we switch rifles. You literally could not see at all. We later switched him to a Leupold VX3i, and the problem was solved. From what I have seen so far, this is not a problem for the 4.5-14x44 BDX scope. I can’t say how the other models, especially those with the larger objectives, would fare, but this model, even when I have tried to blow it out, handled it just fine.

Accuracy

All the tech involved here is useless if it does not provide sufficiently accurate holdovers in the reticle. In addition, what happens if you don’t have a BDX RF? And what happens if the battery dies and you are running old school? To find out, we headed out to the private range where we do some precision rifle training to put the scope through the paces. We tested using the full system, so 3000 BDX communicating holds to the scope (one run using the AB ultralite, one run using AB Elite via Kestrel); using distance hold overs; using MOA holdovers; and using no tech, simply dialing the solution indicated by the Kestrel.

Because this is a private range used heavily for training law enforcement and others, we did not have the luxury of waiting for good weather, so it was a bit tricky with 5-15 MPH gusting winds that changed seemingly randomly from no value to half value. To make it worse, the range is not laid out like many other ranges with all the targets lined out in one direction on a flat plane. In this case, they are in slightly different directions, between random breaks of trees, sometimes in gullies, sometimes in the open, sometimes completely surrounded by trees, so all shots are made from a hilltop.

Targets are set out in realistic hunting scenarios in small openings in the thick cover with variable wind blocks that makes accurate wind calls challenging. The large row on the left runs to 540 yards. The far clearing in the upper left is 1390. The closest clearing on the right runs to 700 and the upper right clearing is 1125​

All that is to say, getting the wind right at this range is always a bit of a challenge, and this day, it was particularly tricky, so we limited our test data to the last plate before 1125, which was the 700 yard plate. Targets were at 150, 200, 300, 400, 500, 540, and 700.

BDX scope with 3000 BDX and Kestrel 5700 and AB Elite

For the first run, we ran it with everything: BDX scope connected to the 3k BDX binos, which were connected to the Kestrel for its solution. The Kestrel was setup to utilize AB’s custom drag model for the 145 ELDX that my son uses in his .270 Winchester Weatherby Vanguard. Shooting from prone off a bipod, we found the holds to be dead on all the way out to 700 yards. Now and then the wind would shift and gust unexpectedly, but bullets still hit plates with windage being off a bit, but elevation was excellent. Overall, communication worked excellently out to about 9 yards or so, with the proviso that you needed to have direct line of site between the RF and the scope, the holds were right, and the workflow was super-fast and efficient.

BDX scope with 3000 BDX and AB Ultralite

For the second run through the plates, we disconnected from the Kestrel and let AB Ultralite provide the solution. We knew this would work out to 500 plus yards because this is pretty much the setup we used in January to make shots on Aoudad out to 571 yards. In that case, we were using this same scope, but had the 2400 BDX with us, but the ballistics engine is the same. Ultralite uses G7 for it’s BC’s, and many bullets, this one included, are selectable as presets. Oddly, I noticed the G7 it populated with was different than what Hornady specified, but we went with it nonetheless, and it worked fine on the Aoudad. However, once we got it on steel at longer distances, we noticed that the solution had us hitting just a bit high consistently. By the time we got to 700, we could see it was off by a pretty consistent .5 MOA (as much as we could tell within the accuracy envelope etc.). To adjust, we did what I do with my Leicas, which is start to tweak the BC until it matches the proven drops provided by the Kestrel. It did not take too terribly much, but we did eventually get it pretty much on. We re-ran the tests from 300 to 700 and it worked like a charm.

 

[catorres1]

Sig BDX Scope Review Continued

To try and figure out what was going on here, I looked at the aero jump and Coriolis numbers that the Kestrel included in it’s solution, and they were near zero based on our DOF etc. So that does not appear to be the reason the drops were off just a bit. So I suspect that the CDM’s for that particular bullet are just that much more consistent and accurate and that is where the disparity is. It’s just a guess, but with my Leicas, when using the onboard ballistics, I have to make the same type of adjustment to the BC (upward) for my heavier ELDX’s. In the case of my Leica, I am usually off closer to 1 MOA at that distance, so Ultralite is about .5 MOA closer to the mark, but in both cases, it just illustrates the importance of truing your data. Sig clearly recognizes this, as the app actually has a somewhat automatic truing feature that we could have used. It lets you designate your impact difference at a given distance, and it automatically adjusts velocity to match what you are seeing on target. We tweaked BC out of habit, but either way we got it done, but it also goes to show how useful it is to have access to a more robust ballistic solution when you start to stretch those distances. Sig’s 2400 ABS has had that capability for a while, but new players like the BDX, the Vec X and Leica’s 2800 take a different route to providing that complete solution.

BDX scope using distance-based holdovers

A feature of the BDX system is allowing the shooter to decide what tech they want to use, or not use, both in terms of amount and brand. So we wanted to test how the scope would work if you did not have a connection to a BDX RF, either because your RF could not broadcast or maybe you are using another brand of RF. Once we had the BC worked out, we gave the plates a run, again, out to 700 yards. As expected, it was a simple task of knowing the distance and holding on the right dot. Of course, you have to remember how you setup each dot, but if you utilize the scope in this manner consistently, it should be second nature. Either way, in our test, it was on without fuss to 700 yards.

BDX scope using MOA-based holdovers

The BDX system also allows shooters to set up to 8 dots in the scope to a desired increment in terms of MOA or Mils. In order to test its accuracy, we set 8 dots up in 2 MOA increments and ran through the plates. Using this system, we had no problem making first round hits out to the 700 yard plate. What I like about this capability is that, like all the holdovers, with Sig’s ‘digital focal plane’, the subtensions automatically adjust to the level of magnification. So if you are using the dots to range, you can use it like a first focal plane scope in that regard. The dots can also be used to supplement your elevation by giving you holdover to add to your dialing, thereby allowing for longer range shots than would otherwise be possible.

Beneath the caps are finger adjustable dials that can be reset to zero. However, there is no zero stop, so you will need to keep track of your revolutions​

BDX scope dialing only

Finally, we wanted to see what would happen if all the electrics went out on the scope entirely and we had to use the scope like any other scope, without the benefit of any of the BDX tech. This was particularly important to me because I hate to have to depend on tech without a backup. When talking to Sig about this, they told me that the scopes did not have a bunch of elevation, they were not really designed with this in mind. However, what you have would track true.

We started by running the scope from top to bottom to see how much elevation we had to work with. In this particular scope, we had just over 50 MOA total elevation. While not a lot, it’s enough to get us well past the 700 yard plate easily. Depending on your setup and location (elevation etc.), 25 MOA will generally get you to 1000 yards, and this could of course be extended by using a canted rail. So while limited, it is probably sufficient for most shooter’s needs in a hunting scope.

To test tracking, we started at the 150 plate and ran it through the targets out to the 700 plate. First round hits were not a problem, impacts were where expected. We then ran it back down to the 150 plate and then back up to the 500 plate and again, no problem. We then returned it to the 100 yard zero and ran it through the whole course again using the full capabilities of the scope (RF indicated holds, and also distance based holds), and it was on. While certainly not a box test, we felt confident it would do the job.

Hunting Aoudad in Palo Duro Canyon gave us a great opportunity to test the BDX system under real world conditions​

Field test

As I mentioned, we actually used the system in the field before the full range test. While somewhat backwards in terms of testing methodology, we got the scope just days before we needed to leave to hunt Aoudad in the Texas panhandle, but we really wanted to give the system a real run in, and this was our last major hunt of the season. So we mounted the scope up on my son’s rifle, sighted it in and did some basic testing to make sure it was going to work and be accurate, then headed out a few days later to hunt. This was previous to us getting the 3k BDX, so we were using the 2400 BDX in tandem with the scope.

Without going too far into the details, I’ll just say that the system worked and, due to its speed, helped make sure my son’s hunt was successful. He was able to pull off a 571 yard shot, and then make an unexpected fast second shot at 270, the second shot made more possible by the speed of the system. Without it, the ram probably would have gone over the edge, but because he was able to just quickly range, drop the RF, and shoot where the dot indicated, he made a good shot and the ram never made it. Using the rangefinder to give him the distance was very important because distance cues in Palo Duro Canyon are totally different than where we live a few hundred miles south, and these hunts are very short, so you don’t really get time to become acclimated to what distances look like. The ability to use a rangefinder and still shoot very quickly under pressure made a big difference here, at least for my son. After our experience on that hunt, any doubts I had about just how effective the system is evaporated. While I maintained my concerns about having to depend on the tech (until my testing verified that the system had viable alternatives built in), I was convinced by its performance in the field.

My son hauling out the Aoudad ram he took using the BDX system in Palo Duro Canyon​

 

[catorres1]

Sig BDX Scope Review Continued

Final Impressions

When I got my first demo on the BDX system, I was really focused on the RF integration with the Kestrel, something I had really been wanting to see for a while. To be honest, when Sig showed me the scope integration during that demo, I basically dismissed it as unneeded, too much tech, and slightly gimmicky. A solution in search of a problem. But the RF’s were really exciting to me, so I obtained a 2400 and took it with me last season to really wring it out. I was impressed by it, and during that time, as I hunted with my sons, thought maybe the scope concept might be a somewhat interesting angle to explore, just to get a deeper feel for the whole system. I still thought the scope integration did not bring much to the table, but thought it might be useful for getting holds sorted when hunting with kids, but not much more. To me, the RF alone was the star. Having used it for several months now under various conditions, my opinion has changed. I am, frankly, quite impressed with the concept and execution of the BDX system as a whole.

Don’t get me wrong, I have some level of discomfort with a bunch of tech, and a great level of discomfort having to rely on it entirely. And working in marketing, I have a healthy distrust of all the useless ‘innovations’ that are constantly hoisted on to the market, hyped to make people buy stuff they don’t really need, and offering little to no real improvement over what they already have. But after seeing how the BDX system successfully compresses the workflow in action, my opinion shifted. In our experience this last season, it makes getting a shot off with fewer mistakes in terms of data entry and implementation easier, faster, and more secure.

Are there ways Sig can improve? Of course. There are various things I mention about the 2400 BDX that I would like to see addressed, and some about the 3k BDX that I’ll cover when I finish reviewing it. Speaking strictly to the scope, I would like to see the tech moved upscale in their line. While the glass is up to the task, I prefer the glass on my VX6, for example, so seeing it move into their higher range would be great. Along with that should come higher power erector arrays, more elevation, and perhaps exposed but locking turrets with clicks that are more positive and a zero stop. Internal to the reticle, I’d like more than 8 dots to be available for holds, maybe 10 or even 20.

But most of these things are ‘would likes’, not weaknesses, at least when you are just looking at the scope. The system works as it is, and I suspect Sig launched it at the lower end to make it more financially accessible to more people. Overall, the system is well thought out, it does what it advertises and, in my experience so far, actually brings tangible benefits to the table for those that want to utilize them in whatever capacity they are comfortable with. The BDX system just makes the tech more streamlined, less fiddly, and less prone to data transfer error by letting all the stuff we are already using communicate. And it does it fast. Some people will be good with that, others, not so much. But regardless, I think there is value in each of the component parts, even as standalone devices, highlighting a notable strength of the system which is, however much of the solution you choose to utilize, the BDX system has something to offer.

 

[joshdidthis]

Great review! Been waiting to hear what the verdict is on this system for a while. It's amazing the technology they are able to pack into what appears to be a normal riflescope. I saw the kilo 2400 bdx and Sierra 3 bdx combo for like $850. Seems like it's an underrated system imo.

Sent from my SM-G950U using Tapatalk

 

[catorres1]

Glad you liked it! Yeah, I was pleasantly surprised by how useful the additional tech actually is. And I think there is a lot more than can be done, especially in terms of pushing the tech upwards in their line...coarse, the price would probably be a problem for someone in my tax bracket!

 

[realunlucky]

I'm curious if you knew off hand what the scope weights?

Sent from my moto z3 using Tapatalk

 

[catorres1]

Think it was right at 23 ounces IIRC.

 

[TNKnoxville]

Awesome review. I have the 3 x 10 and really like it!

 

[catorres1]

Glad you enjoyed it! I am pretty impressed with the scope, obviously. Been testing the 3k BDX for a while, but moved to a new house a few days ago, on some land. Been able to test a little more in a relaxed timeframe, extremely impressed with it's ranging performance. These two together make a pretty awesome hunting system!

 

[TTSX180]

Any new info on the zero stop, can’t seem to find anything.
Great review.

 

[catorres1]

Unfortunately, no, there is no zero stop on this scope. It was designed mainly for use with the holdover system, so they did not add cost by adding a zero stop on this scope. I would probably like to have it, as a backup to when I may not want or be able to use the BDX system, but I think most people would probably rather do without than have to pay additional for this feature.

 

[swampthing]

I am fairly new to this system but recently bought the 4-14 scope with the 3000 binos. I have compared the bdx scope to a zeiss v4 and a new bushnell forge. It wasnt quite as clear trying to read the writing on a target at 100 yards but it is very acceptable. I am really interested in hunting with this system. I am up in BC Canada and there is talk they may outlaw this system up here! I sure hope not! Your review was read several times before I bought this system and it helped me make my choice! Thanks

 

[catorres1]

You are welcome! BTW, I raised the BC issue with Sig last week, supposed to have a call sometime soon to talk more about it. Not sure what they will say, but I'll let you know if they know something we don't. Hopefully, more reasonable heads will prevail!

 

[swampthing]

You are welcome! BTW, I raised the BC issue with Sig last week, supposed to have a call sometime soon to talk more about it. Not sure what they will say, but I'll let you know if they know something we don't. Hopefully, more reasonable heads will prevail!

Thanks catorres!

 

[tdhanses]

Only problem I’ve had with Sig is optics fogging and crappy customer service.