Balistic calculator in scopes, or for that matter in general.

Jump to latest Follow Reply
Peashooter

Peashooter

Member
Apr 9, 2021
4,603
4,448
Denmark
So my friend got the Himicro Alpex lite, and i just picked up the LRF for my oneleaf NV500 scope.

BUT !

We both run into problems with the damn thing actually working.
We can of course enter all the needed parameters, Checked and triple checked, but outside ( further out ) the zero distance we are both shooting too high VS what the scope suggest.

My friend shoot the 13.43gr KO slugs, and i have been giving the JSB Heavy a spin in lack of Hades pellets.
In my friends case the BC is right there on the tin, but i had to dig a little around in the interweb to find a BC for the JSB pellets ( 0.031 )

I have to admit this is a bit confusing for me, and for my not at all technically inclined M8 more than that.

So we can Zero for 30 M and everything is dandy, but then ranging and shooting to 50 - 55 - 62 M and suddenly our shots land 2 to +5 CM too high.
We have not tried shooting shorter than the zero distance.

PS: We are of course not ranging for something behind our targets, they are all large enough that we are not doing that mistake.
Ands we have verified distances with leupold range finder.

The way i see it my only option are to " tune " the BC until it fit CUZ clearly the scope think my shots drop a lot more than they actually do.


Thoughts ? Hints ?? Wisdom,,,,, much welcome.
 
Okay i will have to admit i put in a BC for the JSB Heavy pellets of 0.028 and it should have been 0.031, so in my case that might be the problem.
But on my friends scope there is for sure not a wrong BC entered unless JSB printed a wrong one on the tin.

Height over barrel ( center 2 center )
Height over sea level ( 65 M ) ( official cartographic source )
Barometric pressure
Air humidity
shot speed
ASO

It should all be correct

Air pressure for instance a average of the range weather stations reading ( yes we have that ) and online sources.

Really trying very hard here to use the correct values for the math going on here.

At these moderate distances we are shooting fairly level too, it is after 60 M our range go up a little, so shooting to the very back you are shooting at a 7-8 deg or so up angle.
If anything the 30 M zero distance might be a little down aim, like a few degrees.
 
Last edited:
Upvote 0
Peashooter said:
Indeed a FX chrono and on my rifle also my FCM ( Franken Chrono Moderator ) with the natechrony steadyshot measuring the speed and my rock steady fire position.

All parameters seem so good to go, thats why i do not get it.
Click to expand...
I would put the same data into a different ballistic app. Compare to your scope’s app.

They should both predict approximately the same corrections at all distances. If the other app is correct, but not your scope app, it’s possible that the problem is with the scope app. If neither matches your real world results, it’s likely you are doing something wrong.
 
  • Like
Reactions: Motorhead
Upvote 0
Yeah i am not sure changing to that more correct value is going to be better, but will give it a try tomorrow even if weather is helluva bad, and really i should be building on the shot shed instead.
But figure i can " waste " a hour doing that.

Also contemplating zeroing on a further distance to see how the system cope with shorter than zero scenario.
 
Upvote 0
A update on this.

I did my Zero at 56 M, entered a more valid BC number for the JSB Heavy pellets, and put in the actual scope height over barrel CUZ i had played a little with that.
And wouldn’t you know things are now fairly close to bang on, at least from 28 M and out to 75 M which even on a good day is a stretch for .177 Heavy pellets, mind you there was some wind during this so will have to verify on a more quiet day.
But feeling confident.

In regard to my friends Alpex lite scope, it seem others have ballistic calculator issues too, actually my friends indicate 180 degree wrong, so it it say you need 1.2 MOA hold under for a distance, you do 1.2MOA hold over and then you are pretty much bang on.

PT my friend have just made a couple of zeroed profiles for the few distances he like, and then put his ballistic calculator on pause.

I did manage to kill a few of the "killer snails " last night, they are not very big so my Maverick are working just fine
 
Upvote 0
Peashooter said:
A update on this.

I did my Zero at 56 M, entered a more valid BC number for the JSB Heavy pellets, and put in the actual scope height over barrel CUZ i had played a little with that.
And wouldn’t you know things are now fairly close to bang on, at least from 28 M and out to 75 M which even on a good day is a stretch for .177 Heavy pellets, mind you there was some wind during this so will have to verify on a more quiet day.
But feeling confident.

In regard to my friends Alpex lite scope, it seem others have ballistic calculator issues too, actually my friends indicate 180 degree wrong, so it it say you need 1.2 MOA hold under for a distance, you do 1.2MOA hold over and then you are pretty much bang on.

PT my friend have just made a couple of zeroed profiles for the few distances he like, and then put his ballistic calculator on pause.

I did manage to kill a few of the "killer snails " last night, they are not very big so my Maverick are working just fine
Click to expand...
No insult intended @ Peashooter
There is a popular saying here in the U.S. that is applicable to all forms of data input.
From audio recording thru medical and rocket science it holds true.
Garbage in ,,,,,,,,,,,Garbage out


Now, if you will, tell us about the killer snails, please
Photos appreciated!

Just my 2 in a pod
Edward

Edward
 
  • Like
Reactions: Peashooter
Upvote 0
None taken.
As a old salty sea dog my skin is pretty thick, so people will have to really put a effort in to put a dent in my self esteem.

Sadly i dont think i remembered a single time to press record on the damn scope.
My M8 is a master record button presser but then in turn he always forget to zoom in just a little.

A butt shot again, but 13 grain slugs split these little mice so most of their inside are on the outside.

 
  • Like
Reactions: Pfddi and SilentSquirrel
Upvote 0
Peashooter said:
So my friend got the Himicro Alpex lite, and i just picked up the LRF for my oneleaf NV500 scope.

BUT !

We both run into problems with the damn thing actually working.
We can of course enter all the needed parameters, Checked and triple checked, but outside ( further out ) the zero distance we are both shooting too high VS what the scope suggest.

My friend shoot the 13.43gr KO slugs, and i have been giving the JSB Heavy a spin in lack of Hades pellets.
In my friends case the BC is right there on the tin, but i had to dig a little around in the interweb to find a BC for the JSB pellets ( 0.031 )

I have to admit this is a bit confusing for me, and for my not at all technically inclined M8 more than that.

So we can Zero for 30 M and everything is dandy, but then ranging and shooting to 50 - 55 - 62 M and suddenly our shots land 2 to +5 CM too high.
We have not tried shooting shorter than the zero distance.

PS: We are of course not ranging for something behind our targets, they are all large enough that we are not doing that mistake.
Ands we have verified distances with leupold range finder.

The way i see it my only option are to " tune " the BC until it fit CUZ clearly the scope think my shots drop a lot more than they actually do.


Thoughts ? Hints ?? Wisdom,,,,, much welcome.
Click to expand...

If you zero at 30m and your shots go hight at 50m+, your BC coefficient value is incorrect. I know you entered the manufacturer’s published value. Over the years I’ve realized those values are often “approximately” correct. Furthermore, nearly all ballistic calculators are for faster bullets. So you have to adjust your settings to compensate.

To setup my scopes, I zero my scope, adjust the scope height for distances shorter than my zero, and then adjust my BC coefficient for distances longer than my zero. Below is how…

After zeroing the scope (yours is 30m), I would take a shot at 25m and check the difference between my aim and hit point. If the pellet hit higher than my aim point, I’ll decrease the scope height a bit. If the hit point is lower, I’ll increase the scope height a bit. I’ll take another shot and do the whole thing again until the hit and the aim points are the same.

I’ll repeat the whole process at 20m, 15m, 10m. I know it sounds weird but, I often end up up to 1” off of what I measure as the scope height.

Once that is done, you have to adjust your BC coefficient.

In your case, the pellets hit higher at 50m. That means the pellet does not drop as much as your calculator thinks it should. The reason is simple; your BC coefficient is too low. So increase your BC coefficient a bit and take a test shot at 35m. If the hit point is lower than your aim point, you’ve increased your BC coefficient too high, decrease it a bit. Repeat the testing until the hit point and the aim points match.

Then repeat the same process at 45m, 55m, 65m, …

You are done!

In my backyard, using ATN, I can hit sub-moa up to 74yards.
 
  • Like
Reactions: Peashooter
Upvote 0
You must log in or register to reply here.
Top Bottom
Back
Home
Forums
Resources
Menu