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Got a New Toy

Florida BullfrogFlorida Bullfrog Posts: 3,104 Captain


ATN X-Site 4k Pro. Day/Night digital night vision scope. Of special interest to me is its built in ballistics calculator that will move my reticle to the correct point of impact for targets based on range. Airguns only shoot flat to about 65 yards then they start to drop dramatically. It works by first taking my ballistics data for my airgun (.308 97 grain bullet, 900fps muzzle velocity, .177 BC, 50 yard zero) and then ranging my target by either measuring the top and bottom of my target against a pre-set target height (I'm using the shoulder height of a deer) or by using an optional laser range finder that connects to the scope. The range finder is another $300 and adds nearly a pound to the weight of the scope, so I opted to just use the built in range estimator. 

I did find that for the range estimator to be accurate I have to lie to it. It looks like the calculation algorithm is off. I found that for the scope to correctly range a 3' tall target, you have to tell the scope the target is 1.3' instead of 3'. Then it will calculate the ranges with some degree of accuracy. If you use the true target height, it will add 100 yards or more to the estimated range.

Daytime picture is full color and very clear. 

Replies

  • swampdogswampdog Central FloridaPosts: 929 Officer
    Pretty interesting BF. The quiet report from an air rifle or silenced .22 intrigues me. 
  • Crkr23Crkr23 MelrosePosts: 40 Deckhand
    Could the algorithm calculation be off because of a meter to ft calculation or owner error, example the scope is showing .3 meter instead of 3 ft. .3meter would be a little over 1 ft.
  • Florida BullfrogFlorida Bullfrog Posts: 3,104 Captain
    edited July 1 #4
    The units should be set to imperial. When it measures distance it reads in yards as opposed to meters. It would be odd for the measuring distance to be in yards but the target size measured in meters. 

    I’ll look this evening. The display on the recorded screen is different than what you actually see on the scope. My HUD when looking through displays a compass and  a gyroscope and a lot more data concerning target, range, weather conditions, ect. It seems like it actually says feet somewhere for the target height. But I’ll double check. In fact just using logic it has to be feet. It has deer factory preset for 3.something for height and that can’t be meters or else it would be a 9-10 foot tall deer. 

    Most Amazon reviews indicate the scope’s rangefinder is crap unless using the add on laser. I think it doesn’t work for people for the reasons I’ve already stated. 

    It could be possible that the scope’s algorithm is only factoring in metric even when told not to. 
  • Florida BullfrogFlorida Bullfrog Posts: 3,104 Captain
    The more I think about it the more I bet you’re right. Its calculating height either in yards or meters even though its supposed to be calculating it in feet. If that holds out in testing it would be easy to dial in the precision of the range finder.  
  • Florida BullfrogFlorida Bullfrog Posts: 3,104 Captain
    It is in-fact supposed to measure target height in feet. Here’s the manual. The default height for deer is much larger than I remembered because they are measuring to the top of the head if the deer has it picked up, although I still wouldn’t know of a deer that has a head near 6ft high. Anyhow, this should be easy to test. I can measure my 100 yard gong target in inches then convert it to a yard and a meter decimal and input it in and see if it ranges true at 100 yards. If I can get it to work consistently without having to measure to the ground, a can just set the target size to that of a deer’s vitals and measure the vitals for a yardage estimate. 


  • pottydocpottydoc The thriving metropolis of Umatilla Posts: 3,870 Captain
    Brown bear is a little tough for a air gun, don’t you think?  :)
  • Florida BullfrogFlorida Bullfrog Posts: 3,104 Captain
    pottydoc said:
    Brown bear is a little tough for a air gun, don’t you think?  :)
    I think brown and polar bears, as well as the African big cats, are the only large dangerous animals I've never seen documented airgun kills on. I do know there are airguns that are strong enough to do it at close range because there are lots of documented airgun kills on other African dangerous game that would be comparable to a brown bear such as cape buffalo. But I suspect it isn't legal to use an airgun anywhere brown bears live. But as it is the scope isn't really a dedicated airgun scope. Its contemplated use is on normal firearms. Its just a natural pairing with my airguns for some discrete night hunting. 

    I didn't some testing this evening. It turns out the scope's rangefinding issue must be some sort of glitch or algorithm problem after all. I tried the relevant conversions and found that they didn't hold up. I could convert the target height to the decimals for feet to yards and meters and it was accurate at 100 yards only. At 65 yards the targets would read about 110-120 yards. 

    It did turn out that the box I've been using was 30 inches instead of 36. So I found a box that measured a true 36 inches and found that I got the most accurate readings came from setting the box height to 1.6 feet. That gave me consistent readings within a few yards of accurate at 65 and 100 yards. That's where I'm probably going to keep the target height set. That will roughly correspond to a whitetail from shoulder to hoof. 
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