Q: Tango Fire 4000 or Sightlok RF-1: which should I buy?
A: For most shooters, a handheld rangefinder in a Sightlok RF-1 mount. Paired with a $130 Sig Sauer KILO2200, the Sightlok RF-1 setup wins 6 of our 8 categories and ties 1. The Tango Fire 4000 wins 1. See the verdict.
Q: How did you compare the Tango Fire 4000 and the Sightlok RF-1?
A: We judged both on eight criteria and named a winner for each one:
Q: What’s the best alternative to the Tango Fire 4000?
A: An increasingly popular solution to the “WMLRF problem” is mounting a handheld rangefinder to your rifle using a Sightlok RF-1 rangefinder mount.
The approach has some disadvantages. Overall, however, it’s a more flexible, modular, and cost-effective solution that, depending on the rangefinder you deploy, can actually deliver more accurate results in the field.
The finished setup looks like this:
The Sightlok RF-1 protects your rangefinder from recoil, bumps, and scratches. A polymer hood protects the rangefinder as a whole, and hard rubber covers protect the laser aperture and eyepiece.
Q: What are some advantages of the Sightlok RF-1 vs the Tango Fire 4000?
A:
Quick Detach to range objects you don’t want to point your muzzle at
Keep rangefinder warm in your pocket until needed to avoid cold weather failures
Use superior handheld lasers with superior ballistic software
Roughly $1000 cheaper
Q: What about recoil? Can’t it damage my rangefinder?
A: Handheld rangefinders are designed to survive drops of about 3 feet, and the impact from a 3-foot drop can generate several thousand psi of pressure. The RF-1 spreads recoil so evenly that no spot on your rangefinder takes more pressure than your thumb puts on the range button, a few dozen psi at most. A few dozen psi is well under 1% of the pressure your rangefinder is built to survive in a 3-foot drop. At that margin, the chance of a .308 shot damaging a healthy rangefinder in the RF-1 is effectively zero. In two years of selling the Sightlok RF-1, no customer has reported a rangefinder damaged by recoil. Read our full analysis of the recoil question and watch recoil test videos.
What about recoil? Won’t my rangefinder be damaged if I mount it to my rifle?
To understand the probability of damage from recoil to your rangefinder, we must take into account how much force is being applied by common rifle cartridges like the .308, how that force is distributed, and roughly how close that comes to the amount of force necessary to actually damage your rangefinder.
How much force?
The amount of force is not that great. For example, in the case of a .308, the cumulative force of the recoil is about equal to the force of you picking up your rangefinder and squeezing it hard for a few thousandths of a second.
How is the force distributed?
Beyond the actual amount of force is an even more critical factor: How the force is distributed. The Sightlok RF-1 uses 3M impact-absorbing rubber to hold the rangefinder and evenly distribute the recoil forces while simultaneously shielding sensitive areas like the buttons, the laser aperture lenses, the ocular, and the ocular lenses from impact. Lastly, when the rangefinder is held in the RF-1 mount, recoil force travels straight back along the bore axis, rather than to corners or edges where impact forces can cause more damage. The result of these mitigating factors is that recoil generates about the same amount of pressure on your rangefinder as you exert when you press the range button.
Typical standards for rangefinder durability
Handheld rangefinders are designed to survive drops of about 3 feet, and the impact from a 3-foot drop can generate several thousand psi of pressure.
How close does recoil come to causing damage?
The RF-1 spreads recoil so evenly that no spot on your rangefinder takes more pressure than your thumb puts on the range button, a few dozen psi at most. A few dozen psi is well under 1% of the pressure your rangefinder is built to survive in a 3-foot drop. At that margin, the chance of a .308 shot damaging a healthy rangefinder in the RF-1 is effectively zero.
No reported failures
In two years of selling the Sightlok RF-1, no customer has reported a rangefinder damaged by recoil.
Recoil tests on video
Below, a US military rifleman tests the Sightlok RF-1 with recoil from two common cartridges.
Sig Sauer KILO1000BDX versus .308 rifle recoil:
Sig Sauer KILO1000BDX versus 6.5 Creedmoor rifle recoil:
Q: What about the rangefinder remote? Don’t I lose that feature with the Sightlok RF-1?
A: Yes, you do lose that feature. The Tango Fire 4000 has a wired remote. A Sightlok RF-1 setup typically does not have one (unless you are using a rangefinder with a wired remote like the LE032). This means rather than triggering your rangefinder with your right hand by pressing a remote switch near the trigger, you typically mount your rangefinder on the left or top of your scope, and press the range button with your left hand while holding your rifle with your right. This works fine if you shoot off a tripod, bipod, bag, etc., but it’s a disadvantage if you shoot with nothing to support your rifle except your left arm. The Tango Fire 4000 wins this category: see category 5.
Q: What about weight? Does the Sightlok RF-1 solution weigh more?
A: Slightly more than the Tango Fire 4000.
| Part | Tango Fire 4000 | Sig KILO2200 + Sightlok RF-1 |
|---|---|---|
| Rangefinder | About 14.8 oz for the whole unit | Sig Sauer KILO2200: 7.5 oz |
| Rangefinder mount | Sightlok RF-1: 7 oz | |
| Quick-detach kit | Not needed | Sightlok QD accessory: about 0.9 oz |
| Protective cover | Not needed | Sightlok polymer protective cover: about 2.6 oz |
| Total | About 14.8 oz | About 18 oz |
| Difference | The Sig KILO2200 + Sightlok RF-1 weighs about 3.2 oz more | |
You carry an extra 3.2 ounces, but reap the massive benefit of lower beam divergence from almost any decent handheld, which is a game-changer when it comes down to ranging a target in brush. The tradeoff is easily worth it.
👉 Read on for the head-to-head table and all eight categories.
Or jump straight to an answer: Is the Tango Fire 4000 worth it? · If I don’t already own a good handheld rangefinder, which one should I use with the Sightlok RF-1? · See all FAQs
For this comparison we paired the Sightlok RF-1 with a Sig Sauer KILO2200 BDX, which costs $130. We picked the KILO2200 because its real-world ranging performance is in the same class as the Tango Fire 4000’s, so the comparison is fair on capability rather than stacked with an expensive flagship.
If you already own a decent handheld (Sig, Leica, Leupold, Vortex, whatever it is), it very likely performs as well as or better than the KILO2200, and you only buy the Sightlok RF-1, QD accessory and cover. Everything below holds for that setup too.
Head to Head
| Criterion | Tango Fire 4000 | Sightlok RF-1 + KILO2200 | Winner |
|---|---|---|---|
| Price | $1,500 | $490 | Sightlok + Sig KILO2200 |
| Ranging trees | 1,500 yards | 1,600 yards | Sightlok + Sig KILO2200 |
| Ranging deer and elk | 1,200 yards | 1,300 yards | Sightlok + Sig KILO2200 |
| Beam divergence | Not published; field reports describe the same symptoms as the Vortex Impact 4000 | 1.4 MRAD, round beam pattern | Sightlok + Sig KILO2200 |
| Environmental sensors | None | None on the KILO2200; built into Sig BDX handhelds from the KILO3K up | Tie with the KILO2200 |
| Firmware reliability | Two unfixed bugs that can affect your firing solution | No known equivalent bugs | Sightlok + Sig KILO2200 |
| Wired or Bluetooth remote | Wired remote, instant | No remote: you press the range button with your support hand | Tango Fire 4000 |
| Range without pointing your muzzle at the target | No | Yes: you can quickly detach the RF-1 from the rail | Sightlok + Sig KILO2200 |
| Ballistic software | Applied Ballistics, moving to a cloud app | Sig BDX, actively developed | Sightlok + Sig KILO2200 |
| Company support and warranty | Poor, with documented complaints | Sig’s lifetime warranty, plus US-based Sightlok support | Sightlok + Sig KILO2200 |
The Eight Categories
1. Ranging Performance and Price: Sightlok RF-1 + Sig KILO2200 wins
Wildly optimistic range estimates from the manufacturer notwithstanding, in real-world ranging the $130 Sig Sauer KILO2200 outperforms the $1,500 Tango Fire 4000: 1,600 yards versus 1,500 on trees, and 1,300 versus 1,200 on deer and elk.
You’re paying $1,500 for a product that is functionally inferior to a low-end $130 rangefinder. Think of the Tango Fire 4000 as a $100 rangefinder in a $1,400 box.
The Sig KILO2200 + Sightlok RF-1 setup costs $1,010 less than the Tango Fire 4000. See the price tables.
2. Beam Divergence: Sightlok RF-1 + Sig KILO2200 wins
Visual Proof of the Problem
This night vision photo shows the Vortex Impact 4000’s 45° slash beam pattern. Tango Innovations doesn’t publish a beam divergence figure for the Tango Fire 4000. The Tango Fire 4000 shows the same real-world symptoms in the field, and we think it may actually share the same laser unit that’s used by Vortex.
Numerical Proof of the Problem
| Rangefinder | Beam divergence | Beam pattern |
|---|---|---|
| Tango Fire 4000 | Not published | Field reports describe excessive beam divergence and a diagonal beam pattern |
| Vortex Impact 4000 | 2.0 x 0.2 MRAD | “Slash-shaped,” canted 45° |
| Sig KILO2200 | 1.4 MRAD | Round |
Result of the Problem
Due to the excessive beam divergence, the beam hits more branches, grass and ground around the target, resulting in more false or blended readings than you’d find with better quality, lower beam divergence rangefinders.
Read what Vortex Impact 4000 owners report about the same problem.
3. Environmental Sensors: a tie with the KILO2200
The Tango Fire 4000 has no built-in environmental sensors, so you depend on your mobile phone or a Kestrel to get that data:
Tango Innovations says it doesn’t know why the environmental sensors were left out of the Tango Fire 4000, suggesting that the product was not only manufactured, but designed in China, so the “Designed in U.S.” label is probably disingenuous.
The budget KILO2200 has no environmental sensors either, so with the KILO2200 this category is a tie. Sig builds environmental sensors into every BDX-enabled handheld from the KILO3K up, so you can pick a handheld that has them. The Tango Fire 4000 has no version with sensors.
4. Firmware Reliability: Sightlok RF-1 + Sig KILO2200 wins
Owners reported two Tango Fire 4000 firmware bugs on Snipershide:
A continuous ranging bug that can stop your firing solution from updating. If you hold down the remote button or the range button for continuous ranging, after 2 to 3 ranges the Tango Fire 4000 can keep showing new ranges but stop updating your firing solution, with no warning. See the report here.
An inclinometer bug that can make the Tango Fire 4000 use your phone’s angle instead of your rifle’s. The bug happens with the BOSS phone app connected (see the report here). A firmware bug causes the Tango Fire 4000 ballistic calculator to use the angle you’re holding your phone, rather than the angle you’re holding your rifle, as the shooting angle. So, for example, if you’re holding your phone vertically, as one commonly does, the ballistic calculator thinks your rifle is pointing straight up in the sky rather than toward the horizon. Obviously this can lead to wildly inaccurate firing solutions.
A Tango Innovations representative follows the Snipershide thread, but Tango Innovations hasn’t fixed either bug. A manufacturer that hasn’t fixed the Tango Fire 4000’s bugs is a manufacturer you’re trusting with your firing solution.
5. Wired or Bluetooth Remote: Tango Fire 4000 wins
The Tango Fire 4000’s wired remote is its biggest advantage vs the Vortex because a wired remote works every time and there’s never anything to wake up or reconnect.
The Tango Fire 4000’s wired remote sits by your trigger hand. Press it and you have a range, with no pairing step and no battery drain from a standing connection. The Vortex Impact 4000’s Bluetooth remote either has to stay connected or has to re-pair before you can range.
A Sightlok RF-1 setup has no remote. You press the range button with your support hand. On a bipod or a bag, pressing the range button costs you a moment. If you’re standing, kneeling, or braced against a tree, your support hand is holding the rifle up, and you have to break your hold to range.
The missing remote is the one significant downside of our setup. Pressing the range button is faster than waiting on a Bluetooth remote to wake up and re-pair, but slower than a wired remote by your trigger hand.
If your priority is the absolute fastest range with your hand never leaving the grip, buy the Tango Fire 4000 and accept the rest of what comes with it.
6. Range Without Pointing Your Muzzle at the Target: Sightlok RF-1 + Sig KILO2200 wins
With the Tango Fire 4000, you have to point your weapon at whatever you want to range. This is a major disadvantage in the field. You can’t use the Tango Fire 4000 to scout a distance, confirm a range on something you’re not ready to shoot, or range near other people or livestock without pointing your rifle at them.
You can quickly detach the Sightlok RF-1 from the rail when you want to range a target you don’t want to point your muzzle at, and reattach when you’re done, while maintaining an accurate co-witness between your rangefinder and scope. No dedicated WMLRF can do this.
7. Ballistic Software: Sightlok RF-1 + Sig KILO2200 wins
The Tango Fire 4000 shipped with the “AB Synapse – BOSS” app, which is no longer in development. Tango Innovations is moving owners to Applied Ballistics Quantum, a cloud-based app. Depending on a cloud app means you need an internet connection to grab drag curves or new bullet data, often not practical when you’re out in the field.
Sig continues to develop and support its BDX app.
8. Company Support and Warranty: Sightlok RF-1 + Sig KILO2200 wins
Sig Sauer covers its rangefinders with the SIG SAUER Electro-Optics Infinite Guarantee™, a fully transferable lifetime warranty covering both structural and electronic components. Other handheld makers offer their own warranties.
Sig is incredible with support for electro-optics. If you have a problem with their rangefinders for example, you send yours in to them and they literally just send you a new one. This is a far cry from the kind of support you receive from Henrich/Tango & Co.
Tango Innovations has a poor documented support record. One commenter wrote: “I’ve been texting back and forth with Marcus with the Tangoinnos company… after reading this blog post I realize I’ve been gaslit.” Another owner reported a Tango Fire 4000 that wouldn’t hold zero and a support call that went unanswered for a day. See who is behind the Tango Fire 4000.
And as far as after-sales support goes with Sightlok, like Sig, we have an iron-clad guarantee on our product and we are an American company with American customer support agents and American engineering experts on hand to support our customers. The Sightlok RF-1 is engineered to survive military-level engagements. Put simply, should a problem arise, you’re in better hands with Sightlok and Sig Sauer than you are with Tango Innovations, and that’s particularly important when the price tag is $1,500.
We have yet to receive a return of a Sightlok RF-1.
What Does a Sightlok RF-1 Setup Cost Compared With the Tango Fire 4000?
| Part | Tango Fire 4000 | Sig KILO2200 + Sightlok RF-1 |
|---|---|---|
| Rangefinder | $1,500 for the whole unit | Sig Sauer KILO2200: $130 |
| Rangefinder mount | Sightlok RF-1: $200 | |
| Quick-detach kit | Not needed | Sightlok QD accessory: $90 |
| Protective cover | Not needed | Sightlok polymer protective cover: $70 |
| Total | $1,500 | $490 |
| Difference | The Sig KILO2200 + Sightlok RF-1 costs $1,010 less | |
The KILO2200 has no environmental sensors. For built-in sensors, choose a Sig KILO3K or higher.
What Does a Setup With Built-In Environmental Sensors Cost?
| Part | Tango Fire 4000 | Sig KILO3K + Sightlok RF-1 |
|---|---|---|
| Rangefinder | $1,500 for the whole unit, with no environmental sensors | Sig Sauer KILO3K: $275, with built-in temperature, pressure and humidity sensors |
| Rangefinder mount | Sightlok RF-1: $200 | |
| Quick-detach kit | Not needed | Sightlok QD accessory: $90 |
| Protective cover | Not needed | Sightlok polymer protective cover: $70 |
| Total | $1,500 | $635 |
| Difference | The Sig KILO3K + Sightlok RF-1 costs $865 less | |
If you already own a decent handheld rangefinder, you only buy the Sightlok RF-1, QD accessory and cover, $360 in all, and pay $1,140 less than the Tango Fire 4000. The cheaper option is also the better one.
The Verdict
Sightlok RF-1 + Sig KILO2200: 6 categories. Tango Fire 4000: 1 category. Environmental sensors: a tie.
1st place: Sightlok RF-1 + Sig KILO2200. The Sightlok setup wins ranging performance and price, beam divergence, firmware reliability, range without pointing your muzzle at the target, ballistic software and company support and warranty.
2nd place: Tango Fire 4000. The Tango Fire 4000 wins the wired or Bluetooth remote category.
Build a Better WMLRF Than the Tango Fire 4000
With the Sightlok RF-1, you can:
- Keep your rangefinder warm in your pocket until you need it
- Use almost any handheld rangefinder, so you’re not locked into one brand
See how to turn the rangefinder you already own into a better WMLRF than the Tango Fire 4000
Is the Tango Fire 4000 worth it?
No. See the verdict.
If I don’t already own a good handheld rangefinder, which one should I use with the Sightlok RF-1?
Pick a rangefinder based on how far you shoot. For ultra-long distances, you may need a Sig KILO8K-ABS or a Sig KILO5K. Most shooters can use almost any decent handheld rangefinder, and the rangefinder doesn’t have to be a Sig. Work out the distances and conditions you shoot in, and buy a rangefinder that handles them.
Who is Sightlok?
Sightlok publishes factual, unbiased reports and reviews on electro-optics gear, especially weapon-mounted laser rangefinders (WMLRF). We are the world’s leading independent expert on WMLRF options. We also design and build the Sightlok RF-1. We help you find gear that fits your needs and avoid gear that doesn’t.
Where does this information come from?
We base these reports on our own field experience with the products, on conversations with our customers, and on posts from respected members of forums like Snipershide, Rokslide and LongRangeHunting.
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The Sightlok RF-1 is a Picatinny / Weaver rail mount that turns the handheld rangefinder you already own into a weapon-mounted laser rangefinder.
