Maths question for someone with brains ?

[Jon A]

Yes, as Britz said, you can just divide the dope the computer gives you, in MOA by 1.09 going by those numbers. Or if you have a program that will let you, simply change the click value to match. For example with this one THIS on (listed in the sticky at the top) on the first tab under MOA Value put 1.143 "/100 yds instead of 1.047 and it'll figure your dope correctly. Some programs will let you do that, some won't.

I still recommend doing the yardstick thing (doesn't have to be a yardstick either, just something large measured exactly) because you can get much more accurate results.

 

[Eaglet]

Down Under Hunter,​

+1 to what Jon said.​

That number (25) is pretty interesting. If at 100M you move up 20 MOA's and the impact moves 25 inches, then your scope moves the impact point up 1.25" = 1 1/4" at 100 M per MOA. That means that if you have 4 clicks to one MOA, then 1 click at 100M would equal 0.3125". 4x20=80clicks,
80 x 0.3125 = 25" inches.​

All this translates to say the in your scope 1 Click = 0.29847 MOAs at 100M. Punching this information and velicity and the conditions, LoadBase says the following:​

Note: 20 MOA puts your out to 803M.
16.1 MOA puts you out to 700M. I used a scope height of 2.3".​

 

[Down Under Hunter]

Eaglet, Britz and Jon A

Very well explained !

I'll send the scope back for a fix up after I get done with April hunting season.

At least in the meantime I have my drops worked out to 700 and confirmed with the PDA so in the meantime I'll run with that.

This explains my grief of the last few frustrating practice sessions ?

Basically for every 10 moa dialed I would be getting an extra one !

Also my 100 zero was 1 inch high of centre. So there is our difference !

Many thanks again guys. I'm due for better days from now on !

This stuff is a constant learning curve

DUH

 

[P KUNDA]

Download Pejsa balistics from Benchrest Central for free

Happy Easter all !

The question is this-

I have my rifle zeroed at 100 meters.

If I dial 20 moa up, how many inches should the group move up at 100 M ?

My brain is hurting trying to work this out !

Remember to convert the yards to meters.

Cheers

DUH

,,,,,,,,,,,,,,,,,

Peter

 

[P KUNDA]

Download Pejsa balistics from Benchrest Cental for free

Happy Easter all !

The question is this-

I have my rifle zeroed at 100 meters.

If I dial 20 moa up, how many inches should the group move up at 100 M ?

My brain is hurting trying to work this out !

Remember to convert the yards to meters.

Cheers

DUH

,,,,,,,,,,,

Peter

 

[davewilson]

the real beauty of shooting two groups,one at 100, and another at the same distance after cranking the scope up 20 or 25 MOA, is not only can you tell how far the turrets are moving the point of impact, but you can also see if your scope turrets are tracking on a straight line up and down. this is how i set my croshairs when mounting a scope. keep turning the crosshairs until both groups are perfectly verticle from each other.

 

[Down Under Hunter]

Dave,

One other little curve ball I forgot to mention. When I shot the rifle for its 100 m zero I did not pay enough close attention to the large black spot on the target. In fact the 100 M zero was 1" high.

Due to time constraints and family demands I have little time to shoot the rifle this week to check this stuff, but after reading your posts I have been running some numbers on exbal. Just trying to see if all the math conclusively proves that the scope clicks are inaccurate and the 1 " high 100 M zero is where it all is going wrong.

I unfortunately dont have the time to play with the gun too much as hunting season starts in one week so I'll run with the numbers below. I wont be shooting past 500 M in this season anyway. Then I will make all corrections needed for the rest of the year.

Facts are these

1. When at 100 lasered meters and dialling 20 moa up I have 25 " of group elevation. ( This is above the 1 " high 100 M group )

2. Scope and mounts are good.

3. Groups are super.

I need the following confirmed ups on a NXS 5-22

200m- 1.25 up

300m- 3.25

400- 5.25

530- 8.5 up

Can anyone tell me what my zero would be being 1 " high at 100 M ?

338 edge (2870 fps estimate) 300 smk .768 bc. 20 ft above sea level BP 30.0, RH 46 % temp 76 f ? 2.1 " above bore. These numbers get me close.

If I can work out my the correct zero, stretch the sight in zero on exbal to this and see where the numbers were at ?

If I was close, I thought I'd do as Jon A suggested and divide my exbal dope with the 1.09 suggested and see if I end up with the correct ups listed above ? Hopefully this will then support the scope clicks being wrong ?

Did that make any sense ?

I know I'm trying to cover too many bases at once, but I'm just trying to satisfy myself I have it nailed down now.

Maybe some of you boys who have more experience with exbal than me can see if I am thinking this through clearly ?

Thanks all for your welcomed assistance. I have more calculations and pieces of paper in front of me than you can imagine !

Happy Easter all !

DUH

 

[Eaglet]

Down Under Hunter,​

Your zero would be at 208 m.​

Look at this:​

At 100m 1 MOA = 1.1450"
20 MOA = 1.1450 X 20 = 22.9"
Now 22.9" + 2" = 24.9" So... I'd say that's close enough to 25.0".
Then I would say your scope is dead on!!! ​

 

[Down Under Hunter]

Eaglet,

Thanks for your thoughts.

As hunting season is only a week away I have the scope dialed accurately out to 940 M. After next week I plan on reshooting the 100 zero, do a ladder test, chrono the rifle, then take it to the range again for trajectory validation..

For what ever reason I cant get the pda exbal to match anywhere near the actual drops with a 2800-2850 speed. Always need a faster speed.

These are my drops tested and confirmed.

200 m 1.25 up, just high 1-2 "

300m 3.25 up, Just high 1-2 inch

400 5.25 up, Dead on !

530 8.5 up - DEAD ON !

700 M Got 15.75 up from exbal, divded by 1.09 = 14.5 up 3" high- Ill take it !

940 M Exbal gave 24 up so I divided that by the 1.09 as suggetsted to factor larger click values and got 22 up. Fired and landed at the base of plate. I would say 15 " low. The I ran out of rounds. I figure 23 up would be more like it. What do you think ?

Thanks boys, sorry to trouble you all but am rushing to get some drop numbers confirmed. I would not expect to shoot it next week past 600 anyway !

Cheers mates !

DUH

 

[Eaglet]

DUH,​

Are you still 2" hight at 100m?
When your talking about the values going up, are you talking about MOAs or the values on your turrets which are 4 clicks to an inch at 100 yards?​

 

[Down Under Hunter]

Eaglet,

The gun is still set 2" high at 100M.

When I talk aboout moa's I'm reading off the turrets, 4 clicks to an inch.
I plan on changing that immediately after my first season next week as I dont have time to verify the drops beforehand.

The values I list are MOA at 100 yards.- 1.25, 3.25, 5.25, 8.5, 14.5 and 23 ? as read off the NXS turret.

Can you see any pattern with this flight trajectory to suggest a prediated 2800 ish velocity with a 200 M ish zero. This is what feel Im dealing with. Until I can verify I'm trying to run some numbers and see if anything makes sense on exbal.

I ran a scenario that got me real close with 2940 fps and 140 M zero. But who knows. I'm happy to dial the above next week as they have all been confirmed on paper.

The one thing to remeber thoug is that 100M group moved 25 " up when 20 moa was dialed on the scope. This group was measured from the 2 " high group above the bull.

Thanks mate

DUH

 

[davewilson]

DUH, if you know what your drops are, why do you want the computer, especially if you're only shooting 600? i'd leave that thing at home and work off the drop chart.

 

[Down Under Hunter]

Dave,

I hear what you are saying mate !

I set this rig up for far greater shots though. This is just the first mission it will have. For what I want to do, I want the computer support to roll with conditions and corrections.

DUH

 

[Down Under Hunter]

Down Under Hunter,​

Your zero would be at 208 m.​

Look at this:​

At 100m 1 MOA = 1.1450"
20 MOA = 1.1450 X 20 = 22.9"
Now 22.9" + 2" = 24.9" So... I'd say that's close enough to 25.0".
Then I would say your scope is dead on!!! ​

G'day mate !

Just want to make sure I get this clear. Are you saying that with my 100 m point of impact being 2 " high, then after turning my NXS two full turns ( 20 moa or 80 clicks ) my group should have moved up 25 " above the first group ? Thus making the second group 27 " above the bull ?

If this is so, I feel much better about the scope clicks being correct. I just thought the group should only have moved the 22.9 ".

Hope you can clear that stupid look off my face.

many thanks

DUH