Ballistic calculator for close/mid range pesting

[Floridaman2005]

I do have an ATN X-Sight 5 LRF 3-15X and a Thor 5 XD LRF 3-30X. Once I figured out how to set up their ballistic calculators, target practicing became so simple; I just measure the distance, point the crosshairs to the target and shoot. That’s it. No more manual clicks, or holdovers or anything else. The results are extremely reliable. I am really happy with the ATNs.

The problem is figuring out how to set up the ATNs. Ideally, you should be able to enter your projectile’s BC, your scope hight, and pellet speed, and you should be good to go. Well, I was not that lucky.

First, you cannot use the scope hight you measure. You have to find your real scope hight I’ve started from 26 yards (where the scopes are zeroed, and tested the daystates at decreasing distances, all the way down to 10 yards. I lowered the scope hight a bit if the hit point was above the aim point (and vice versa). In both of my daystates, the measured scope hights were almost 1” higher than the ATN settings (one was 0.9” and the other was 0.8”).

Then I had to adjust the BC. Normally, the manufacturer’s BC should be enough. Well, it turns out, ATN calculates the drop amount using some equations and adjusts them using a look-up table. Unfortunately, they don’t have any data for slow projectiles (pellets /slugs). So, the look up does not work well. To compensate, I’ve tested the daystates starting from 26 yards to 74 yards, at 10 yards increments. If the pellets hit above the aim point, I increased the BC a bit (ATN obviously thought, the pellets should have dropped more). If the pellets hit below the aim point, I decreased the BC by a bit).

At this point, my daystates and I can hit within 1” for distances up to 74 yards, and up to 5(ish) degree elevation change. Anything more than 5 degrees, the spread goes above 1” for distances more than 50 yards. I still don’t know why.

Great information. Thank you for that. This makes me more confident in my Athlon scope. While I like the idea of the point and shoot ballistic calculator scopes, I don’t want to have to finesse it into working properly. I used a free ballistic calculator program to calculate everything for me and then printed and laminated a dope chart with all of the distances I would be shoot at. It has all the mil holdovers/clicks that I would need and once I convert the chart to memory, a simple range finder should be sufficient.

Thanks!

 

[Pfddi]

@Floridaman2005 - I got an Element 1500 rangefinder that takes a BC from their free iOS/Android app and will automatically give you the holdovers when you range the target! You don't have to memorize it once it's loaded. It will hold 4 profiles so you could do 4 guns and switch the profile for the gun you are using that hunt. So far I have 2 profiles in it and took it to the range and it worked like a charm. The only drawback is the red reticle and writing - hard to see when it's really bright outside and you can't change it to black or another color.

 

[OldDude]

Great information. Thank you for that. This makes me more confident in my Athlon scope. While I like the idea of the point and shoot ballistic calculator scopes, I don’t want to have to finesse it into working properly. I used a free ballistic calculator program to calculate everything for me and then printed and laminated a dope chart with all of the distances I would be shoot at. It has all the mil holdovers/clicks that I would need and once I convert the chart to memory, a simple range finder should be sufficient.

Thanks!

I hope you don’t think I am a “know it all” but even with a dope chart, IMO, one should do something similar to what I described above.

In my experience, the BC numbers published by the manufacturers are some approximations. For example, JSB Match Diablo Hades Monster .22 I am using has BC 0.041 (measured by me), although JSB documented it as 0.033 (that’s what I found in the in the internet some time ago). That is kind of a big difference. But easy to adjust. After zeroing the scope, you just take a shot at a distance much larger than your zero-distance. If the pellet hits high, you increase your BC. Simple.

Same goes for the scope height. When a rifle’s zero distance is 100 or 200 yards, the scope height being off by 0.8” becomes negligible, especially when your target is a 5” circle. However, we the precision shooters, every minute variation counts (please, don’t say no. We, the most of the air gunners, are all obsessed with hitting submoa targets ). So, calculating the “true” scope height is important for shooting targets closer than our zero-distance.

In my opinion, if you want to be precise, you should test your pre- and post-zero distances and adjust your scope height + BC numbers. This is irrespective of using a chart or a scope with a ballistic calculator.

 

[TonyP]

a LRF rangfinder with balistic calculator or a digital scope are game changers.. I have a Element titan Range finder with balistics and it works mint. You can also import current weather conditions so your dope will always be on point. And for a digial scope i had a Zulus lrf and i currently have 2 Thermnights and they work amazing..

 

[OldDude]

I do agree wholeheartedly for LRF. However, I have to respectfully disagree with you on the digital scopes. I have not found a digital scope, which could rival a Swarovski or Zeiss (or Kahles or …). Their views become pixelated when zoomed in.

Unfortunately, Swarovski/Zeiss/… don’t have a scope with a range finder for air gunning (the Swarovski dS has an integrated range finder but its parallax correction starts from 50 meters).