Leupold RX2800 TBR/W Rangefinder
By Major Rob Robinette
I'm a huge fan of the RX2800 rangefinder. It is an amazing value for a serious long range rangefinder. Not only will it really range beyond its 2800 yard factory spec but its glass is so good it also acts as a 7x spotting monocular. It functions as a ballistic calculator for shots inside 600 yards and uses a built-in inclinometer to compensate for uphill/down hill shooting. You can of course input the rangefinder's range and incline numbers into a ballistic calculator for a more precise shooting solution than the RX2800's built-in calculator.
When wind display is turned on the elevation will be shown for about 1 second, then the wind will be displayed with a "W" in place of the "E" shown above. If you miss the elevation display just push the power button again to get another reading.
If you are lucky your load is listed in the owner's manual TBR/W PERFORMANCE GROUPS: LOAD TABLE (page 21 of the owner's manual) but for most of us our load won't be listed. To set up the ballistic calculator to match our rifle and load we must match our load ballistics with the RX2800 TBR/W Load Group Selection Table (shown below from page 25 of the owner's manual).
Here's how to determine your "Load Group Number" to make the RX2800's ballistic solution as accurate as possible. The RX2800 uses Load Group Numbers to categorize rifle ballistics. To find our Load Group Number we'll compare our load's ballistics to the RX2800 Load Group Selection Table:
My 6.5Creedmoor Tikka T3x TAC A1 shooting Hornady factory ammo 147gr ELDM at 2665fps has a 600 yard bullet path height of 72.5 inches and 21 inches of wind drift at 600 yards. Using the 200 yard zero section of the chart puts me into Load Group 10.
Use your favorite ballistic calculator to work up three range tables:
1. Use a 200 or 300 yard zero, zero wind and 600 yards as max range. If you use a 100 yard zero then put a 200 yard zero in the calculator--we will correct for the 100 yard zero in the next section. If you use a zero greater than 300 yards then put a 300 yard zero in the calculator. Write down the 600 yard trajectory in inches.
2. Add a 10mph crosswind from 3 o'clock or 90 degrees and write down the 600 yard wind drift in inches. We do a separate chart to keep vertical wind jump out of our elevation number.
Note: If you use the Hornady 4DOF ballistic calculator you can select No Wind Trajectory and Wind Drift and add a 10mph crosswind and not have to do two range tables.
Don't use "Total Come Up" and "Total Windrift" because they contain crosswind aerodynamic jump and spin drift.
These numbers must be in inches to use the RX2800 Load Group Selection Table. I use the free online Hornady 4DOF calculator. Be sure and select the units as inches, not MOA or Mils.
With value #1 and #2 go into the RX2800 TBR/W Load Group Selection Table (shown above) and find where your numbers fit in. You have to match the zero range (200 or 300 yards), #1 trajectory and #2 wind drift in the chart. When you match all three you get the "Load Group Number" you will enter into the RX2800's setup menu. Turn the RX2800 on then hold the Mode button for more than 2 seconds to enter the setup menu. Press the Mode button to move between fields and press the Power button to select values to set your Load Group Number.
For example, my Tikka T3x TAC A1 in 6.5 Creedmoor zeroed at 200 yards with Hornady 147 ELDM factory ammo generates a muzzle velocity of 2665fps. This load gives me 72.5" of bullet path height and 21" of wind drift at 600 yards. That puts me into Group 10
100 Yard Zero Correction
If you are like me and don't use a 200 or 300 yard zero that the Load Group Selection Table needs we can calculate a correction to compensate (I am amazed Leupold didn't include a 100 yard zero in the Load Group Selection Table).
Again use your favorite ballistic calculator to create two range tables selecting mils or MOA as the units:
1. Use a 200 or 300 yard zero (whatever is closest to your actual zero), zero wind and 600 yards as max range. Write down the 600 yard trajectory in mils or MOA.
2. Use your actual zero, zero wind and 600 yards as max range. Write down the 600 yard trajectory in mils or MOA.
No Wind Trajectory at 600 yards with a 200 yard zero is 3.36mil.
Subtract #2 from #1 to get the correction. You will need to add or subtract this value to the ballistic elevation displayed in the RX2800. Add the correction for a zero less than 200 yards and subtract the correction for a zero greater than 300 yards.
For example, I zero my rifle at 100 yards so I subtract #2 3.36mil from #1 3.73mil to get the correction of 0.37mil. I round that up to 0.4mil and add 0.4 to the RX2800 elevation mil display to compensate for the 100 yard zero. The elevation correction is the same at all ranges.
Wind
The RX2800 wind solution is for a 10mph direct crosswind and does not need to be corrected for your zero range.
Use half the displayed crosswind solution for a 5mph direct crosswind. Double the solution for a 20mph direct crosswind.
Use this wind clock to adjust winds other than a direct crosswind:
US Marine MCTP 3-01E wind clock system.
If the wind is in our face or back (12 or 6 o'clock) we disregard the wind correction.
If the wind is a crosswind from 2, 3, 4 or 8, 9, 10 o'clock we use the full wind correction from the rangefinder.
If the wind is from any other direction (1, 5, 7 or 11 o'clock) we cut the wind value in half.
The RX2800 ballistic solution is plenty accurate for hunting at 600 yards or less. For longer ranges I use the very accurate Applied Ballistics Mobile app.
The RX2800 can be set for yards or meters and can display ballistic numbers in MOA or Mils. Both are set in the setup menu.
P.S. I love this freakin' rangefinder.
By Major Rob Robinette
US Army and Air Force (Retired)
Major Robinette was a Battalion Marksmanship Champion, Squadron Rifle Team Captain, Range Officer and F-15 pilot. Rob also spent 10 years as a federal law enforcement officer. He holds a Federal Firearms License and is the owner of Nolichucky Guns. He enjoys all forms of rifle and pistol use.