Rangefinders are not on every hunter's must have list of hunting tools. However the last ten years, as prices have dropped and ease of use increased, has seen a surge in the adoption of rangefinders among hunters. Manufacturers have noticed the increased interest among hunters and have produced a steady stream of new ranging devices over the last couple of years.
In 2006 Leupold entered the rangefinder market with their RX line of ranging devices. The RX series are named much like the VX line of popular Leupold scopes where an increase in roman numerals signifies an increase in sophistication and cost. The RX-I is an entry model that is stripped down and offers basic ranging features. The RX-II is similar in shape, weight, and size but has a built in inclinometer that helps to calculate ballistic range to a target. The RX-III and RX-IV are a different shape and size and offer an extra button to help toggle and set the various ranging modes of the device. The RX-III and RX-IV both have an illuminated display, while the RX-IV alone offers a built in compass. Maximum ranging distance is 750, 750, 1200, and 1500 yards as you move up the scale in model number. However, effective ranging on a non-reflective target, such as deer, will be more like 500, 500, 700, and 800 yards for the same models.
We chose to review the RX-II rangefinder because it is the least expensive model (street price of ~$300) which includes an inclinometer. To the best of our knowledge the RX-II is the least expensive consumer rangefinder that offers the ability to measure the shooting angle between you and your target. As seasoned bow and rifle shooters know shooting on an angle affects the ballistic distance to your target. The Leupold RX-II attempts to correct for this fact to give you a better estimate of the range to target, which they call True Ballistic Range (TBR).
Knowing the angle between you and the target is important, because only the horizontal leg of the triangle formed between you and the target is important in calculating bullet drop. Line of sight (LOS) on an angle is always longer than the horizontal distance, which is established by the Pythagorean theorem. As an example the Leupold literature with the RX-II notes that a 400 yard LOS shot on a 30 angle (decline or incline) will have a TBR of 364 yards. This can make a large difference in projectile drop depending on velocity.
Leupold takes this one step further by telling you how much correction you need in either minute of angle (MOA) or inches for your particular cartridge or arrow speed at a given distance (with angle correction if necessary). Arrow speeds are broken into three groups, less than 215fps, 215 to 250 fps, and greater than 250 fps. Rifle cartridges are broken into seven groups that also gives you the distance at which you must zero your rifle in order to get the right drop correction for a given range. Leupold even gives a nice chart that helps you to pick the right ballistic group for reloaders that use velocity/bullet-weight combinations that do not easily correspond to the standard charts.
In our testing, the RX-II delivered accurate measurements of LOS and TBR. We used the range finder on a range where known distances corresponded accurately to the read out on the RX-II display. The incline or decline measurement also corresponded well when shooting a range up or down hill. The drop adjustment calculations were also accurate for a given cartridge, which is not surprising since Leupold worked with Sierra's Infinity Exterior Ballistics program to develop the drop adjustment calculations. The Infinity program is well known for delivering accurate ballistic calculations.
View through the RX-II. The rotary menu is on the outside of the ocular ring. Setting different modes causes different tabs to be displayed. Currently the mode is set to Bow mode with B arrow speed and LOS on.
All the sophistication of the RX-II comes with a big downside: complexity. The features of the device must be set and navigated through while looking through the ocular on a rotary menu. The rotary menu in itself is rather clever for organizing the many functions of the device, however the constant toggling of one or both switches can make it difficult to figure out which mode you are in and switching out of it. The RX-II even has 13 different reticles, which is complete overkill since you have to toggle through them when working your way through the settings. One simple duplex reticle would have been sufficient for our testers.
The RX-II comes with a crib sheet of sorts that is conveniently tucked away in the carry pouch. The card describes how to navigate the device and the ballistics tables if you should need to reset them in the field.
It is fairly easy to accidentally hit the mode button while ranging, thus putting the device into a different mode. This can be annoying once you have taken the time to configure it and then have to put it back in your carefully selected mode. It would be nice to have a lock function on the RX-II, such that once you have selected the configuration you want it can't be accidentally put into another mode without unlocking first.
Unfortunately our initial test sample had a broken inclinometer. It simply would not read angles and gave strange LOS readings. Fortunately, Leupold's tech support was easy to work with by phone and verified that the inclinometer was in fact broken. The device was sent back under warranty. The RX-I and RX-II offer a one year warranty, while the more advanced models offer a two year warranty.
View through the broken RX-II. Notice that unlike the photo above the inclinometer would not display an angle. It just appeared as "--".
You must approach the RX-II from the outset that you're going to read the owners manual and become proficient in operating the device. You may also want to consider the RX-III or IV because it offers separate power, set, and mode buttons that make it easier to navigate and use the rotary menu. In short the RX-II is not for the technically faint of heart, if you have a hard time setting up a VCR or DVD player we recommend you steer clear of the RX-II and pick a simpler rangefinder. On the other hand, if you're willing to get past the difficulty of figuring out how to configure and use the RX-II it offers a great value with superior ranging and ballistic information for either the bow or rifle hunter.
For more information about Leupold laser rangefinders visit www.leupold.com .