# Sighting in at 50 for 250?



## Bo0YaA (Sep 29, 2008)

Ok so I've got my wifes 7-08 shooting around 1/2" groups and 100 and now its time for me to actually take her out and adjust the gun to her rather than me. Normally I would adjust my group at 100 yards to reflect whatever range I want my 0 to be, then double check at 200. Because my wife isn't an experienced shooter, I was thinking of trying the method of sighting the gun in at 50 to reflect the 0 I'm looking for. From everything I've been reading, if her POI at 50 is 1.7 inches high she should be dead on at 250 based on the velocity and BC of the bullet we are using. I will have her shoot a few round at 200 just to check but I was curious if anybody has used this method before and how reliable it was. 

For those wondering why I would do it this way rather than the standard way? My thinking is giving her the ability to establish confidence in her own ability and in the rifle shes using. We all know how easy it is to shoot small groups at 50 yards. If she was to shoot at 1/2" group at 50, right at 1.7" high her confidence level would grow leaps and bounds that she she could shoot a deer at 250 off a good rest.


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## wyogoob (Sep 7, 2007)

That's a great way to do it, especially for youngsters or people like me that have some eyesight issues.

I was weaned on shotgun slugs and centerfire rifles with iron sights so for years we sighted in at 25 yards and then a longer distance dependent on the caliber and whether the gun had iron sights or scope. You didn't have to worry about wind drift and it was easy to see your hits on the target with binoculars. I would use this chart from Weaver, circa 1970. It shows the popular calibers of the day, kinda interesting:



Now I use a slightly different approach using a computer ballistic program. Say I want a 250-yard zero with my .308 150 grain Partitions going 2700 fps. I punch in all the stuff i.e. weather, scope height, BC, blah, blah, blah. The ballistic program then says for zero at 250 yards the load will be zero at 28 yards. So I sight the gun/loads in at 28 yards - match bullet holes at 28 yards. After that I'll shoot the longer distances and fine tune if I need to.

Uh...did I tell ya I missed my ram?


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## DallanC (Jan 13, 2009)

As the author of PointBlank Ballistics, I'll be blunt and say if you want to know where your bullet is hitting at XYZ yards, you need to set up a target at XYZ yards and shoot it.

Ballistics are only approximations, there are alot of variables in play... but with good data, computer models can be extremely accurate. I get people all the time asking what their drop will be for their 270, without giving me information like what bullet is it, what velocity is it... /sigh.

People still dont understand the mechanics all too well. Goobs chart above were really useful when most bullets had similar, lower Ballistic Coefficents. Today, its amazing the drop difference in say a 277 Accubond and a 277 LR Accubond. You want to model proper drop you have to get very specific on the information you are inputting into a system.

That said, for simple fun "whatif" scenarios, I have 3 flavors of PointBlank people can use, all are completely free. There is the online only version, there is a PC version and I have somewhat bare bones Android version out there I published more as a resume entry than anything. Play with any of those, if you have questions on ballistics I'm happy to answer them here or over at the 'Nut.

Online Web Version: http://huntingnut.com/index.php?name=PointBlankOnline

PC Version: http://huntingnut.com/index.php?name=PointBlank

Android: https://play.google.com/store/apps/details?id=com.huntingnut.com.pointblankballistics&hl=en

-DallanC


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## Bo0YaA (Sep 29, 2008)

Dallan, just so ya know, I am a huge fan of your program and use it every single time I have a question regarding ballistics. In fact, I used it to come up with the 1.7" high at 50 should put me close at 250 based on all the info I plugged in.


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## DallanC (Jan 13, 2009)

Great, always glad to hear when someone finds it useful. Surprised alot of people still dont know about it. Sierra Bullets used to tell people about it when asked for software suggestions.

I've seen screen shots of PB data results posted in various magazines discussing bullets and ballistics.


-DallanC


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## Bo0YaA (Sep 29, 2008)

So now that you know what program I'm using, providing all the info I input is correct, do you believe I will be close enough to the numbers it claims at 50 vs 250?

One question I have always had about the program is this. Is there a way for the program to calculate the difference between the sight in elevation and actual shooting elevation as well as temperature when sighting in vs hunting. Or, is the difference insignificant enough that it is unnecessary. 

I didn't know you had a smart phone version, I will have to check it out. I've always used Strelok+ in the field.


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## gdog (Sep 13, 2007)

When's the iPhone version coming out?


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## DallanC (Jan 13, 2009)

It will work, the reason I dislike it is a small error at 50 yards is a big error at XYZ yards. Use the ballistics, play around, learn the behavior of your rifle and ammo... BUT at some point everyone who has a "XYZ yard zero" better double check that zero by actually shooting at that range.

My muzzleloader has a 130 yard zero, with a PBR of 150... I confirmed this by shooting paper at 130 yards and making fine adjustments.


-DallanC


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## wyogoob (Sep 7, 2007)

DallanC said:


> As the author of PointBlank Ballistics, I'll be blunt and say if you want to know where your bullet is hitting at XYZ yards, you need to set up a target at XYZ yards and shoot it.
> Yes, did you read my post?
> 
> Ballistics are only approximations, there are alot of variables in play... but with good data, computer models can be extremely accurate. I get people all the time asking what their drop will be for their 270, without giving me information like what bullet is it, what velocity is it... /sigh.
> ...


Thanks

.


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## DallanC (Jan 13, 2009)

wyogoob said:


> Thanks
> 
> .


Are we in some kind of competition or something I am unaware of? Slow day in wyoming I guess.

-DallanC


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## wyogoob (Sep 7, 2007)

DallanC said:


> Are we in some kind of competition or something I am unaware of? Slow day in wyoming I guess.
> 
> -DallanC


Every day's a slow day in Wyoming.

.


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## wyogoob (Sep 7, 2007)

DallanC said:


> As the author of PointBlank Ballistics, I'll be blunt and say if you want to know where your bullet is hitting at XYZ yards, you need to set up a target at XYZ yards and shoot it.
> 
> Ballistics are only approximations, there are alot of variables in play... but with good data, computer models can be extremely accurate. I get people all the time asking what their drop will be for their 270, without giving me information like what bullet is it, what velocity is it... /sigh.
> 
> ...


DallanC's program is a good one. I used it for some odd-ball calibers back when he first posted it on the UWN. I liked playing with the graph thingies.

.


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## LostLouisianian (Oct 11, 2010)

wyogoob said:


> Every day's a slow day in Wyoming.
> 
> .


Wyoming...where men are men and sheep are SCARED !!!!


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## wyogoob (Sep 7, 2007)

Bo0YaA said:


> So now that you know what program I'm using, providing all the info I input is correct, do you believe I will be close enough to the numbers it claims at 50 vs 250?
> 
> One question I have always had about the program is this. Is there a way for the program to calculate the difference between the sight in elevation and actual shooting elevation as well as temperature when sighting in vs hunting. Or, is the difference insignificant enough that it is unnecessary.
> 
> ...........................................................


Not to take anything away from DallanC's program but the Hornady Ballistic Calculator advanced program has entry boxes for elevation, temperature, height of scope, humidity, barometric pressure, wind, other stuff:
http://www.hornady.com/ballistics-resource/ballistics-calculator

Hornady also has the 4DOF Ballistic Calculator that calculates ballistics based on the drag coefficient. I haven't tried it yet:
http://www.hornady.com/ballistics-resource/4dof


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