Zeroing Scope at 50 Metres: How to Compensate?

DarkAisling · #1 10-06-2011, 08:11 AM

If I zero my scope @ 50 metres, how will POI be affected at 100, 200, & 300? I would like the scope to be zeroed at 200 yards (yes, mixing units of measure). Will windage and elevation be affected, or just elevation?

Finnlight 25-06 with VXIII 4.5-14x40 B&C.

I don't remember what rounds I purchased for it (they're at home, and I'm not). They might be the the 117g Hornady Superformance SSTs? Or, maybe the 117g Hornady Customs? (Caber, what the heck did I buy?

).

densa44 · #2 10-06-2011, 08:14 AM

If you know what ammunition you have, there are excellent tables on line that show you where the bullet is all along its trajectory. I'll let the real experts explain how to use the tables. It has worked fine with my 223, we had to find the MV and bullet weight to pick the correct graph, but that was it.

DarkAisling · #3 10-06-2011, 08:29 AM

I do have a couple of ballistics apps on my iPad. "Ballistics" has Hornady tables. I'm a little fuzzy on how to work them, but I've figured out a little bit by fiddling with it for the Superformance. I understand the "drop" but not the "windage" numbers (but I think those might be related to another setting that I haven't figured out yet).

Looking at the table, it looks like a zero at 50 (yards) is also a zero at 150. The drop between 150 and 200 is -1.68 inches (seems like a lot). So, that would mean that I would need to be shooting 1.68 inches high @ 50 to be zeroed at 200. Right?

gitrdun · #4 10-06-2011, 08:35 AM

Zeroing the scope at 50 with the hopes of hitting a target
at 300 is a bad idea Shelley, especially with a rig and ammo that is new to you. You do realize that you have a private shooting range at your disposal.

DarkAisling · #5 10-06-2011, 08:43 AM

Quote:

Originally Posted by gitrdun

Zeroing the scope at 50 with the hopes of hitting a target
at 300 is a bad idea Shelley, especially with a rig and ammo that is new to you. You do realize that you have a private shooting range at your disposal.

Yes, I do.

Thank you! I am taking #1 son to the Edge for his birthday (so he can shoot some "evil black guns"

). I thought I might see what I can accomplish while he burns through a couple hundred bucks worth of ammo.

My actual goal is to zero at 50---hoping to be nicely on paper at 100---but I am thinking about all of the math involved, and how things change at distance.

Rod1960 · #6 10-06-2011, 08:45 AM

I can't say how accurate or useful it is but I like to play around on this:

http://ballisticscalculator.winchester.com/

FallAirFever · #7 10-06-2011, 09:00 AM

Shelley,
I went onthe Federal ammo website and did a comparision between a few of the loads they offer similar to yours. Here is the link (I hope) http://www.federalpremium.com/produc...e_compare.aspx

Looks to me like half an inch high at 50 will give you a zero of 200 and just under 7 inches low at 300. Of course this is only a starting point but should get you close.

Good luck, and have fun out with your son. I love taking my boys out shooting, I think they do to!!

Big Daddy Badger · #8 10-06-2011, 09:22 AM

I zero at 25 for (roughly) 200 then tweek to bring it home while shooting at 200.....300 etc

Works well for most centerfires...

Regardless of what range you use to getit on paper...you need to confirm at the distance you atre zeroing for.

Here is a table that I find handy....

http://www.chuckhawks.com/rifle_trajectory_table.htm

elkhunter11 · #9 10-06-2011, 06:53 PM

Quote:

Zeroing the scope at 50 with the hopes of hitting a target
at 300 is a bad idea

+1

Robmcleod82 · #10 10-06-2011, 07:02 PM

If your at the shooting edge get your rifle on paper, then you can use the private range at your desposal to get it set up right for 200. If your on paper at 50 yards you should still be on paper at 100 and only need to make minor adjustments

#11 10-06-2011, 07:34 PM

Big game Info has a good program. You'll need the ballistic co-efficient of the bullet, the muzzle velocity and grain of bullet. I've tested it with numerous types of ammo and she's pretty darn close.

gitrdun · #12 10-06-2011, 09:39 PM

Quote:

Originally Posted by Robmcleod82

If your at the shooting edge get your rifle on paper, then you can use the private range at your desposal to get it set up right for 200. If your on paper at 50 yards you should still be on paper at 100 and only need to make minor adjustments

You're absolutely right Rob. But I'm still trying to figure out Shelley's intentions in the long run. The point that I'm trying to make is that if you're shooting paper and you need a day out with the kid, then fine. But ballistically speaking, those ballistic calculators are nothing more than a theoretical basis on which to sight in a firearm. Many times over as I have checked these over against real time shooting, the ballistic programs have been proven to be off. Bottom line, there is absolutely no replacement for trigger time and target time. And why the heck wouldn't you wanna do that in the first place.

DarkAisling · #13 10-06-2011, 09:56 PM

Quote:

Originally Posted by gitrdun

But I'm still trying to figure out Shelley's intentions in the long run.

Shelley doesn't know either. She just improvises as she goes along.

Short term goal is just getting reacquainted with ballistics (I LOVE physics), and killing time while my eldest burns through the Shooting Edge's ammo like it's free. Hopefully when I'm done I'll be nicely on paper @ 100. If I can be on paper @ 200 I'll be deliriously happy.

Someone has suggested I enter the postal match (if I submit targets that I haven't hit do I still need a signatory?

), so I might desend on you for an afternoon to get her dialed in and see if I can hit anything.

gitrdun · #14 10-06-2011, 10:07 PM

Quote:

Originally Posted by DarkAisling

Shelley doesn't know either. She just improvises as she goes along.

Short term goal is just getting reacquainted with ballistics (I LOVE physics), and killing time while my eldest burns through the Shooting Edge's ammo like it's free. Hopefully when I'm done I'll be nicely on paper @ 100. If I can be on paper @ 200 I'll be deliriously happy.

Someone has suggested I enter the postal match (if I submit targets that I haven't hit do I still need a signatory?

), so I might desend on you for an afternoon to get her dialed in and see if I can hit anything.

Shelley, you come out and shoot with the boyz, bring the kid. I'll bring the red commie baby killer gun and plenty of ammo to make 'im smile. You'll get a chance to stretch your Finnlight's and your's legs out to ranges that you thought out of range. You'll be amazed at the differences with the ballistic programs and what YOU and your rig print on paper. Of course, there will be refreshements afterwards.