Question on ZERO point

Gremlin · Posted: Sat Aug 01, 2009 11:17 am Post subject: Question on ZERO point

Hi guys.
I have a load that I would like to use for my 300wsm that is shooting 1/2 an inch low at 100 yds.
When I enter that into the data via the target (bullet impact point) the data still shows me as zerod at 100 yds but in fact I am low, so any down range data is going to be wrong.
How do you adjust the data to show that I hit the target 1/2 in low at 100yds
I could adjust the scope to bring it to a 100 yd zero but that wouldn't help me with the downrange point of impact question.
I just wanted to see where the bullet would hit given the half inch drop at 100yds.
Thanks

Pumpkinslinger · Posted: Sat Aug 01, 2009 6:00 pm Post subject: Re: Question on ZERO point

Fudge it by changing your "target distance" to something like 60 yards and see what you get.

Then my next questions are...

Why don't you just adjust the scope?

Why would you zero a .300 WSM at 100 yards?

English Mike · Posted: Sat Aug 01, 2009 7:28 pm Post subject: Re: Question on ZERO point

Pumpkinslinger wrote:

Why would you zero a .300 WSM at 100 yards?

Couldn't agree more.

2" high at 250 gives a hit in the kill zone of an elk all the way from muzzle to just short of 400.

whittling · Posted: Sun Aug 02, 2009 2:42 am Post subject: Re: Question on ZERO point

1/2'' isn't that bad .

chambered221 · Posted: Sun Aug 02, 2009 6:58 am Post subject: Re: Question on ZERO point

Mess with the “target zero distance” until you find your 100 yard figure at -0.5

Don’t worry about the 25 yard increments that are shown, target zero distance will still compute with other yardages but may not show your zero on the read out.

chambered221 · Posted: Sun Aug 02, 2009 7:12 am Post subject: Re: Question on ZERO point

That's harder to do than I thought !!! The closest I got with my load was -0.1

Pumpkinslinger · Posted: Sun Aug 02, 2009 7:42 am Post subject: Re: Question on ZERO point

Yep, somewhere around 60 yards was as low as I could get it, using a load for a 7.5 Swiss. That brings up something I'd like to see in the next version, the ability to have target distances under 50 yards. I load a lot of handgun and would find that pretty useful.

tikkat3 · Super Member Joined: Jul 30, 2006 Posts: 800

I've zeroed mine at 200.
It's 1" high at 100

Dawgdad · Posted: Mon Aug 03, 2009 7:17 am Post subject: Re: Question on ZERO point

Gremlin wrote:

Hi guys.
I have a load that I would like to use for my 300wsm that is shooting 1/2 an inch low at 100 yds.
When I enter that into the data via the target (bullet impact point) the data still shows me as zerod at 100 yds but in fact I am low, so any down range data is going to be wrong.
How do you adjust the data to show that I hit the target 1/2 in low at 100yds
I could adjust the scope to bring it to a 100 yd zero but that wouldn't help me with the downrange point of impact question.
I just wanted to see where the bullet would hit given the half inch drop at 100yds.
Thanks

A 1/2 inch at 100 yards is 1/2 moa shift. I believe that would carry out at distance so that if the table said you would be -4" at 200 yards you would need to take another 1/2 moa or 1" @200 to get -5".

I do this the other way when sigting in my service rifle iron sights My point of aim is 3 moa below my point of impact at all distances with a six o'clock hold on the standard targets. If I am sighted correctly at 100 yards, I do not have to correct for the 18" distance from the bottom to the center of the black at 600 yards. (3 moa). I just use the drop straight from the data table.

Conversely - since you are not correcting for it at the beginning you will need to adjust for it on the back end.

My real question is why do you have it set at 1/2 inch low at 100 yards? As others have said, that class of bullet is best utilzed by setting point blank zero to about 300 yards. Which is about +2.5" up at 100 yards. but we need to know your MV andBC to be sure.

Gremlin · Posted: Mon Aug 03, 2009 7:45 am Post subject: Re: Question on ZERO point

Dawdad-
I didn't set it up to shoot 1/2 in low ........it was bang on dead center for a previous load, different weight and brand bullet.
I was testing out two or three different loads for best group size and this 165gr barnes TSX just happened to hit that point on the target and a string of five shots went from right to left from center by 1/2 in apart but low by 1/2 in.
So I was just curious as to point of impact down range and couldn't .....still can't figure out how to enter the data into point blank so that I would get data that reflected my true point of impact on the target.
I will adjust the scope later for distance when I decide which load gives me the better group size Very Happy

If the computations take the impact point as low and figures out the math correctly then I won't worry about the data showing a zero of 100yards.
I just thought that when you enter point of impact on the enlarged target and then open the other screen it would read as 1/2 in low on the zero line but it still shows as 100yds zero both on the graph and on the data line.
No big deal I'll just adjust the scope. Very Happy

Gremlin · Posted: Mon Aug 03, 2009 7:51 am Post subject: Re: Question on ZERO point

Thanks to every one who responded.
all final adjustments to scope will be made for my distances after testing is completed for my best group sizes.
Bear, Whitetail Deer and Moose are the game of choice there is no Elk season yet in Ontario.
They (MNR) keep tellin us and I qoute "someday"
Thanks again

DallanC · Site Admin Joined: Jan 18, 2005 Posts: 3572 Location: Utah

Yup the others answered it. You need to fudge the target distance until you get a value at X yards you are looking for.

-DallanC

Pitt55 · Posted: Mon Aug 03, 2009 12:15 pm Post subject: Re: Question on ZERO point

I think maybe where you are confused is shots plotted on the target screen have no effect on the trajectory or data tables. The target screen is just to record groups. To get 1/2" low at 100 you have to change target distance on the data sheet till it shows 1/2" low at 100. Hope this helps.
Don

Pitt55 · Posted: Mon Aug 03, 2009 12:32 pm Post subject: Re: Question on ZERO point

I just tried my suggestion on one of my loads for my 300win. You can't go low enough with the target distance to get 1/2" low at 100. Closest I could get was -.01" magnum loads just shoot too flat.

Gremlin · Posted: Mon Aug 03, 2009 1:09 pm Post subject: Re: Question on ZERO point

Okay Now I understand!!!!!
the target has no bearing on the data it's just a still picture of my shots for personal reference....DUH!!!!! The light just went on.....hahahahaha thanks guys.. I can cancel that appointment with the shrink now..Whew!! Very Happy