Ballistic calculators disagree with my actual elevation amounts - help please!

[Ronws]

Blunt because it is the internet?

Probably so. Is that a reason to be blunt? Or do people sometimes lack communication skills?

But also, yeah, we all can be misunderstood in our intention in saying something.

I was in another forum on a different subject and this one guy came off as a pompous ass in writing. But he was soft-spoken and engaging when speaking in a video.

 

[GrahamC]

So coming back to this quite some time later as I think I now understand the problem as to why at 200 yards I had to dial down 0.25MOA from my 100 yard zero which makes no sense.

Having recently changed my scope on my AI I had to re-zero at 100 yards, which I did on a wind free day. After establishing this I then shot a string of 40 rounds which on the electronic target were all scored in the 1 inch center ring. Sounds great, BUT looking through my scope I could see a large hole in the target on the edge of the center ring at 11 o'clock. So actual POI did not tally with what the electronic target was telling me.

The electronic target sensors are in the corners of the large backing board, the actual target is smaller and should be correctly centered but as shown recently, wasn't by maybe 0.5 to 1 inches.

So I expect the original variance was that either the 100 or 200 yard target wasn't correctly centered hence the -0.25MOA oddity.

I still see deltas between what ballistics apps suggest for elevation vs. reality (e.g. at 600 yards AB Quantum suggests 12.8MOA, real life is 13.5), however it's close enough to get me on target. As I'm using a chrono and weather meter I expect this is either variance on round to round velocity of inaccurate BC at different distances.

 

[smoothy8500]

actual POI did not tally with what the electronic target was telling me.

Yeah, if you had said in the first post that E-targets were being used, a few of us would have asked "did you calibrate the targets?"

ShotMarker and Silver Mountain have to be calibrated, because the electronics will say "center" where it "thinks" is center. You would check your electronic scales to confirm 49 grains is really 49 grains when reloading, right?

Electronics are great, however, you always "trust" but verify.

 

[Taylorbok]

That is more discrepancy than I'd like to see at that distance. I'd say something is still off or maybe your zero is still off, not sure if you ever corrected that issue.

If it works for you that's fine.

 

[GrahamC]

Yeah, if you had said in the first post that E-targets were being used, a few of us would have asked "did you calibrate the targets?"

Fair comment. The range technicians manage the electronic targets, we're not allowed into the butts so have no access to them. One would hope that they calibrate them correctly but with 108 targets on the range (admittedly not all electronic) calibration may be ... variable.

I didn't mention electronic targets at the time as it didn't occur to me that they may not have stuck the target in the right place!

 

[cas6969]

I shoot at a range with known distances from 100....

Old thread. Didn't read any of it.
But a couple years ago I couldn't figure out where the error was coming from and it was driving me nuts. I was overlooking the simplest thing, that the known distances were wrong. Looking for tiny complex errors, I was missing simple ones.

 

[JerkyFreak]

For a shooting discipline with sighters, it doesn't really matter. You shoot your sighters and adjust from there.

It has also become more common for f-class the adjust the target so that the actual shots are either 1 to 1.5 moa high or low. In this way the shots do not shoot away the scoring rings at 3 and 9 o'clock the shottists use as aiming points.

 

[GrahamC]

Old thread. Didn't read any of it.
But a couple years ago I couldn't figure out where the error was coming from and it was driving me nuts. I was overlooking the simplest thing, that the known distances were wrong. Looking for tiny complex errors, I was missing simple ones.

Have measured the target distance from the 100, 200, 300 and 600 yard firing points with a laser rangefinder and they're accurate to with 1-1.5 yards. At least part of that discrepancy can be explained by the fact I was measuring from the bench which is behind the actual front edge of the firing point.

So a valid point but not a factor for me in this case.

 

[Partsunavailable]

Sounds like you found a big source of your error. Glad you stuck with it and gave us an update. I wouldn't have thought about an electronic target problem. I'm also guessing that you've come a long way in your ballistic education in the last 6 months if you are still analyzing this issue.

 

[GrahamC]

That is more discrepancy than I'd like to see at that distance. I'd say something is still off or maybe your zero is still off, not sure if you ever corrected that issue.

If it works for you that's fine.

When I saw the POI through my scope I did adjust and felt confident that POA and POI were then correct. The discrepancy is only at longer distances and I agree isn't ideal but if it enables me to get on target I can then adjust.

 

[GrahamC]

Sounds like you found a big source of your error. Glad you stuck with it and gave us an update. I wouldn't have thought about an electronic target problem. I'm also guessing that you've come a long way in your ballistic education in the last 6 months if you are still analyzing this issue.

Thanks.

Have I come a long way? Dunno. I do have a better appreciation of the complexities than I had last year.

Last month I did an F Class training course (out of interest, it's not really my desired discipline and my kit isn't right for it) and they started us off on establishing a 100 yard zero. Some people took 10-15 rounds to establish that. I only had to fire 3 shots to confirm

 

[smoothy8500]

It has also become more common for f-class the adjust the target so that the actual shots are either 1 to 1.5 moa high or low. In this way the shots do not shoot away the scoring rings at 3 and 9 o'clock the shottists use as aiming points.

We do the same, and quit calibrating the targets due to the constant changing of POI/POA on the screen.

With that said, shooters should be skeptical of using an E-target to establish a hard zero, unless it's their own target with confirmed calibration.