Thread: Tall target test

i can only say it works for me, i certainly don't say anything about what Greg D does, that would be crazy, certifiable . .. i dont have a concrete bench to put the scope in a special jig or anything like that, wish i did, i work with what i have.

i dont shoot at 1000yds . . . mostly its subsonic, rimfire and centerfire out to 350-400yds with come ups of 65MOA or 260clicks or more . . . the shooter is always the weak link, you need the shooter for load development, finding a good zero, varifiying POI at distance etc etc . . . but then say ' the shooter cant be trusted to do a simple ladder test to me . . is crazy . .. but i would say that, being crazy myself.


thats all i am saying.

R.

Originally Posted by rossi.45

i still have verify everything at the ranges i shoot, still have to fiddle with the balistic app to make everything fit . . . but i enjoy doing it . .. i am crazy, but it keeps me off the street, keeps me shooting . . thats good.

R.

But you are doing exactly what I say in the film (?) - quantifying the total error.
Or did I misunderstand something? Are you identifying the exact error between the actual scope clicks and the manufacturers claim? If no, we are doing the same thing.

cheers Norway . .. i will have to get back to you when i have enough time to give a full explanation . . . what i will say now, is i think Brian Litz is on the right path ( it does have merit ) but he doesnt go far enough for my liking . . . i shoot every 5MOA untill i run out of elevation or paper.

R.

Norway- How come you're not allowed claw hammers?

A claw hammer ruptures the troll skull and the area require fluid sanitazion by public officials.
A blunt hammer implodes the troll brain without seepage and you can just leave them until daylight and cart them away as solid stones.

Clear as mud

i must say Norway i find your jokes about as clear as some of your videos . . . maybe just a cultural thing . . anyway.

a benchrest shooter once wrote there have been more good barrels changed because of faults with a scope than shooters realise . . . i took that on board and decided i would do my best to test with the limited gear and knowledge i have.
i look to people like Brian Litz . . . sorry for the constant name dropping, but it is important that we keep in mind where the advice is coming from . . its not just internet opinion . . its coming from the Man.

i go a few steps more than Litz . . because i like to shoot, a lot, to test myself, can i keep the bullet holes going up the line . . and of course test the scope all the way thru the elevation, not just a couple of places and devide the result.

once i have the result i use that value on my app . . then i fine tune the BC & velocity to reconcile the different range POIs for a broad rang of conditions

my next project i will be dialling up +100MOA so i better have my shit together . . . maybe i am wrong, could be, its happened before, but i do enjoy the journey

R.

Yes, then I understood correctly. That is quantifying the total error.

I am not concerned about what Litz is saying. Me and Litz agree. The benchrest guy is likely writing about scope repeatability, which I do not question.
If your scope cannot hold zero, the group will open up. If you are shooting at a fixed range, the tall target test (measuring the angle of the click correction) does not matter as you only need to know how many clicks to dial the bullet into that range and for the scope to hold zero. (Knowing the required comeups for the range vs knowing the actual adjustment angle for the scope)

I am saying when you have a +/- 1 meter range error built into the laser rangefinder it is matemathically impossible to calculate a fixed number, you will end up with a bracket. If you must multiply 1 (click) with an unknown number between 99 and 101, then you cannot know the correct answer is 100. It could just as easily be 99 -99,1 -99,2 etc etc.

Also, if your bullet impacts one bullet diameter high or low (which most would consider a perfect hit) you introduce a measurement error much larger than the laser brings to the test.

So no, I do not believe a tall target test by shooting will say anything PRECISE about the scope adjustment angle per click.
I believe you can find if the scope is repeatable and if the shooter can avoid canting.

Mr Litz is demonstrating a method for general consumption - and a very definite improvement over knowing nothing about your scope's tracking. It addresses the issue of cant and gives a rough idea of the accuracy of the turret adjustments, while still being simple enough to perform so as to hopefully not put folk off giving it a try. Consider though that what he recommends in the videos and the way he tests his own scopes may be two very different things.

The most revealing approach is to use a method that eliminates all but the one variable that is of interest - say in this case the accuracy of the tracking. I was about to say best but if you want only a rough idea of the accuracy of the tracking then the tall test is certainly easy enough to perform. And it may be quite rough, depending on the sort of groups the rifle shoots on the day.

It isn't that difficult though to clamp a scope rigidly enough to get good data on the tracking. It is less problematic to do this with the scope alone though and not having it mounted on a rifle.

http://www.nzhuntingandshooting.co.n...tml#post238269

I have a very good peaty Islay here that will explain it all and solve the worlds problems by the time we consume it.

Originally Posted by Gibo

Could it be your bc?

Would that be Lagavulin, Laphroaig, or (preferably and) McCellands? The Islay strain is surely my favorite...

In an earlier post I mentioned my come-ups were accurate to about 700 yds, then past there I was hitting high. So I've just done my version of the tall target test. I "tied" the rifle down to the table and had a target at 100yds. I put up a target with inches marked out.
5 MOA moved 5.5"
10MOA moved 11"
15MOA moved 17"
20MOA moved 22.25"

So it has a pretty consitent error. 1MOA in my scope is 1.1" rather than 1.047"
At 20MOA the error was the most so 22.25@/20MOA = 1.1125"
So in shooter I've applied a correction factor 20MOA should be 20.94". So I went 20.94/22.25 to get 0.94112360.
Without the correction factor at 980yds I had to go up 25.1MOA, with the correction factor I only have to go up 23.6MOA, so 1.5MOA less. Which amounts to 15.3" at 980 yds, which is about how high I was on the target.

At 700yds without the correction the come-up was 14.7MOA, with the correction factor up 13.9MOA so 0.8MOA difference or 5.8". Shooting at a rock I obviously didn't notice it. (The 980yd target was a large plywood sheet, so I could measure it)