Applied Ballistics correction value math help!!

[Bart B]

Originally Posted by LouBoyd

But D2 changed as you focus a scope to new parallax settings as the target distance is changed.

I've never had a rifle scope that focuses to any parallax settings. Nor do I think any scope does that. Do parallax settings have any unit of measurement? Does parallax stay the same once set? I don't think so.

Parallax is apparent movement of the reticule on the target image caused by the shooter's aiming eye being off the scope's optical axis behind the eyepiece and the scope's not focused on the target. When the aiming eye's on the scope's optical axis, there will never be any parallax between target image and reticule regardless of what range the scope's focused at. And parallax varies with how far the aiming eye's off the optical axis as well as the difference between target range and the range the scope's focused at. The only thing that adjusts where the eye's at is the shooter moving his eye. And his eye ain't connected to the scope's focusing adjustment.

[bigngreen]

OK, I think I got it I agree it's a small value but I can measure it and verify it so why not, it was not long ago when Coriolis was the big non issue and guys shouldn't worry about it but when you look at it is a factor that one can dial so it needs to factored in when ELR shooting. If I'm shooting far enough to see a difference in the correction the program gives me so I want to nail it down.
I tested optics that were way more of, this Sightron Slll is the tightest I've tested so far.
My test rig allows me to set up the optic in the rings it's going to be mounted one the rifle with so I can test the value of the turrets, set it to dial vertical and lock it in the rings then set the scope level then transfer it to a rifle ready to rock.
The rig has allowed me to dial up and down 80+MOA and check repeatability multiple times with accuracy at 300ft from the target face to the center of the turret, I repeated the test at different power levels and it does not change the value.
I tested an optic that was way of but I've worn 4 barrels out shooting under it and I know what it is, in a half hour with no shots fired I tested it and it came out to the same value I've been using from trial and error. So if I test every optic I instal it will just make life go easier and barrel life can be used on important things!!
I know if your value is of you'll fight velocity and BC trying to get the trajectory right but it will screw with you till you find the value!!

[Mikecr]

I think it's important to ballistically account for scope adjustments in the field(for single shot kills).
So I test adjustments & set level like bigngreen.
So far I've found (3)Mk4s to be MOA(to the best of my measure), and (2)NF NXS to be ~1.09 IPHY.

[elkaholic]

Originally Posted by bigngreen

OK, I thought I had this all straight but then I started reading and figuring and one thing lead to another and now I don't know what I know.

I tested an optic by turning it up 120 clicks which puts me at 30 whole numbers of some value I'm trying to determine, the optic moved 31.5 inches so I took and divided actual movement of 31.5 inches by dialed movement of 30 and it came out at 1.05 which I'm thinking is what my actual turret movement is in since it was done at 300ft and MOA should be 1.047 at that distance. So I'm thinking that's .003 over correcting at 300ft for MOA and so the correction factor would be 1 minus .003 which is .997, but then I read the directions and they seem to have you dividing dialed value by actual value and that is your correction factor which comes out as .952 so I think that's it but it does not look right!

JacknSD put it like this in another thread trying to help but my brain ain't gettn it so I though I best move to another thread!! Maybe I need the why you did it the way you did written out? Thanks for helping!!

"If you meant 30 MOA moved it 31.5 inches at 100 yards then it would be: .997

30*1.0471996=31.415988

31.415988/31.5= .997

So almost no correction seems to be needed. "

All I have to say about this problem is "I WANT YOUR SCOPE"!.........RICH

[Eaglet]

Originally Posted by elkaholic

All I have to say about this problem is "I WANT YOUR SCOPE"!.........RICH

That's it! I want it too!