Does anyone else make something like this?

[squirrelsnpr]

If this works as it says, it will help me out a lot. Seems like I'm always chasing my 0 depending on conditions. I hate guessing or firing a sighting round.

http://www.jbmballistics.com/ballisticomp/ballisticomp.shtml

From what I understand this device will retain environmental conditions from one day to the next and provide adjustments needed to re-zero your rifle depending on the environmental"differences".For example if you were shooting in high hummity and cold weather one day and zeroed your rifle and then shot in low hummity and hot weather the device would tell you to adjust the tuurets b/c you would have a point of impact that shifted up.

 

[PLeighton]

Re: Does anyone else make something like this?

Yup...

http://www.kestrelmeters.com/Kestrel-4500-NV-Bluetooth-Horus-ATrag-Ballistics.pro
MSRP $669

 

[prestong]

Re: Does anyone else make something like this?

Just get an iphone/ipad, it automatically obtains weather conditions via gps, and does all the bullet calculations.

 

[Chiller]

Re: Does anyone else make something like this?

absent the Kestrel

you are looking for "close" will have to do for conditions.

 

[squirrelsnpr]

Re: Does anyone else make something like this?

Chiller could you clarify for me?

My issue with current ballistic programs is that they assume your rifle is zeroed in the conditions you have just inputted. When the atmospheric conditions change your rifle is no longer zeroed. I have shot from month to month and have had my point of impact be off a full mill from 200 to 1k. Now that my zero is off the elevation on my dope card is incorrect. Does this make sense?

 

[gugubica]

Re: Does anyone else make something like this?

You need to be using density altitude, its just easier.

Asside from that, every program I am aware of lets you input your zeroing conditions and the current conditions, including the cheap programs for iphone and android phones.

I have 8 range cards for every caliber each with a different DA, it will affect bullet performance, so you need to account for it. Altitude, temprature, pressureand humidity changes will change your POIs at range, DA is one number that makes adjusting easier.

Another variable is changes in muzzle velocity with temp. This is recordable and trackable, so not a big deal either. Most modern powers are very temp stable and not a huge deal though. Varget has a 8 fps shift from 108 degrees to -16 degrees for me, so I don't account for it.

 

[Ratbert]

Re: Does anyone else make something like this?

I was working on making something like that a while ago, but lost interest when it became clear I was going to have difficulty finding an enclosure I liked without having to custom commission one. iPhones are fragile and difficult to use with gloves or in rainy or dirty conditions. If JBM has a rugged build quality to this and a reasonable price then it could be a handy little toy.

 

[PLeighton]

Re: Does anyone else make something like this?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MitchRE</div><div class="ubbcode-body">My issue with current ballistic programs is that they assume your rifle is zeroed in the conditions you have just inputted. When the atmospheric conditions change your rifle is no longer zeroed. I have shot from month to month and have had my point of impact be off a full mill from 200 to 1k. Now that my zero is off the elevation on my dope card is incorrect. Does this make sense? </div></div>
When a 100 yard zero is used, the POI shift from the conditions you zero'd in compared to conditions your currently in will be minimal and fairly predictable.
The two big things that I concern myself with are lighting conditions and whether or not I have a shift in my cold bore POI.
Other than those two things, at 100 yards pressure and temp will cause minimal shift. (Less than one MOA.)
So, if your zero was 100 yards, 12ft ASL, and it was sunny, all you should have to do is make the appropriate adjustment to your dope for the current conditions.

I use a Kestrel meter and old school laminated dope cards.
PDAs just were way too slow and distracting for my taste.
I use software to make my own cards for the conditions that I anticipate encountering and tweak as needed.
(The tweaks are typically no more than 1/2 MOA adjustment to my dope card and once the tweak is found I just add one or two clicks to my adjustment.)
As a backup, I also carry a Schwiebert Precision Ballisticard for M118-LR and an analog density altitude calculator for a base reference.
The process is much simpler than it sounds.

I've seen some good competitors left high and dry when their PDA / iPod whent tits up. (Cough, Cough, Sean Little...)

Electronic Doping vs. Dope Cards are a discussion for another thread though.

If this doesn't make sense to you Mitch, let me know and I will go into greater detail.

 

[Ratbert]

Re: Does anyone else make something like this?

I ended up doing pretty much the same as Dr. Phil.

I've got charts giving me DA from temp/altitude that I can check over the course of the day. Then I've used JBM to build drop/drift charts for my load from 200-1100 @ DA's of -2000 to +7000 in 1000' increments. Printed in 6pt type this entire chart fits on a sticker that goes on the back of my Mildot master.

The chart isn't terribly different that the Field Density Altitude Compensator, just not as fancy. But it is custom printed for my load and easily replaceable/adjustable if I discover more accurate real world data or change something about my setup (new barrel, different load, etc.)

 

[Ratbert]

Re: Does anyone else make something like this?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MitchRE</div><div class="ubbcode-body">
My issue with current ballistic programs is that they assume your rifle is zeroed in the conditions you have just inputted. When the atmospheric conditions change your rifle is no longer zeroed. I have shot from month to month and have had my point of impact be off a full mill from 200 to 1k. Now that my zero is off the elevation on my dope card is incorrect. Does this make sense?</div></div>

Most quality programs these days have separate fields for entering "Zero Conditions" and "Current Conditions." Even so, if you've got a 100yd zero that's shifting by a full mil month to month then I have to wonder if possibly there are not larger problems than changing atmospheric conditions at play.