I do not think that a gps is a good rangefinder. The first question you must ask your self is what degree of accuracy are you looking for. Using one of my favorite 150 grain loads from my .270 Winchester I find that the bullet drops 4-inches between 400 yards, and 425 yards. Between 700 and 725 yards the drop is over 10.5-inches.
You find your self tucked under the edge of a tree canopy, mid-slope looking across a drainage. Your inexpensive gps unit is only receiving three satellites. If the unit is not loaded with a Topo software programs with maps for the area you have lost the battle. If your gps is loaded with Topo software you can guess the location of your target, and using the Panning Arrow option and scroll to that location and determined the distance. But you might have to do a little math in the process.
A given is that the longer a gps has been in a stationary position the more accurate the reading. Setting in my computer room I just turned on my Garmin 76CX(advance chip), it is currently receiving seven satellites, and giving me accuracy of + or – 37 feet. As it sets in place the accuracy should increase. But do you have that much time? The key to getting any timely reading in the field is to have the gps fired up when you leave your vehicle. That way can lock on to some satellites and lock down its location on Earth. I have set my Garmin 76C(discontinued) in the same chair. The chip in the 76C is comparable to what you would find in many of today’s inexpensive units. When doing side-by-side testing with my older Garmin Legend it was comparable. The 76C just sound a tone and I received a pop-up saying that I had poor satellite reception. I am only receiving one strong satellite signal. Being inside a home with a tree canopy on the outside blocking the sky challenges a receiver. Another issue is that satellite reception changes all the time because of the obit pattern of the satellites. I do believe that reception has improved in that last 12 months.
So if your unit tells you that your accuracy is + or – 37 feet that gives you a target area of 74 feet or 24.6 yards.
I think a gps can give you a very general idea of the range. A hunting partner and I was looking at a distant side hill and trying to guess the range. I grabbed my gps and scrolled across the map and came up with a distance over 600 yards to the ridge top which was best defined area on the map. I then scrolled down the side hill to the location I was looking at. It gave me a reading of about .3 miles or 528 yards. I have not been back to that location since my wife gave me a rangefinder, so I just went to Google Earth and obtained a measurement of .23 miles. Or 404+ yards.
A few years ago I was out shooting in a remote area. I measured the distance with my gps. Later in the day another shooter drop by and he asked how far I was shooting. He then pulled out his laser range finder and said I was off about ten yards.
My wife gave me a Nikon Laser 800 rangefinder for Christmas. I find it easy to use, and I have been running around getting the range of deer and other objects. I am trying to develop techniques so that I can take advantage of the technology if needed during deer season. In many cases I believe determining the distance across a canyon ahead of time is wise.
The Nikon is easy to use. Just look through the glass, push the power button and the crosshairs come up. Put the crosshairs on the target and press the power button again and it gives you a reading in yards or meters. I have found that keeping the crosshair on distant game can be tough if I am a little shaky. It is best to use a rest if available. I have found that if a deer is standing in a tree/brush line that a reading on a surface close to the critter will get me very close. I take both my gps and rangefinder on my daily walks so that I can practice with them. Based on my experience a gps does not hold a candle to a rangefinder when it comes to determining and accurate distance. One of my questions is has the advocate of using a gps as a rangefinder used it along side a rangefinder for any period of time.
At this time if I was looking to buy a small gps with high sensitivity I would go for the Garmin Legend HCX. But I would also buy a 2 GB Micro SD card for around $24 and Garmin’s new Topo 2008 software. You can increase your options going into higher price ranges.
BUT if you are looking for a rangefinder, buy a rangefinder. I thought I could use a gps as a rangefinder, but having spent days since Christmas doing a side-by-side comparison the gps does not cut the mustard as a rangefinder, it is a more accurate range-guesser.
