Applied Ballistics Shoot Thru Target Challenge

[Spin Drift]

If a load shoots 1/2 Moa at 100 yards, theoretically it should shoot 1/2 moa upto transonic range? Of course I'm removing shooter error and wind here.

Not necessarily. If your load has any spread in velocity (all loads do) this problem will magnify more and more the further down range you get. I don't think this really shows up at 100 yards.

Sit down with your favorite ballistics calculator and play with changing the velocity by 10 to 30 fps and see what change that equates to at long range. Most people don't have a load with an extreme spread under 10 fps (I'm not there yet either, ES of 15 is my best 5 shots tested so far). There are probably a lot of guys on this forum with less than ten but this forum has an unusual collection of talented handloaders and some of them have the best equipment this game has to offer.

There are of course many more factors to this and maybe Bryan or someone will delve into that.

When I first started loading, lot of "experts " told me to test my loads at longer ranges(200 to 500) because what works at 100 yards may not work at 1000. But based on this thread if average dispersion of a given load is 1/2 moa it should stay 1/2 moa till it hits transonic range? So can I say it doesn't matter if I develop load at 100 or 300yards, if it groups good at short range it will group good at any range as long as shooter is upto task?

I think you have gone backwards with this. I think the point of this thread is to prove or disprove that if a group for example prints 1 MOA at 300 yards it cannot print more than 1 MOA at 100 yards. This discussion does not at all suggest the opposite which would be that if a group is 1 MOA at 100 then it should be 1 MOA at 300.

This doesn't mean for a fact that you cannot do load development at 100 yards. There are different schools of thought on this. Dan Newberry has a system he uses to develop loads at 100 yards. You can read about it if you Google 'Optimal Charge Weight'. I have been experimenting with this system but I am not far enough along into it to say that it works for me or not.

Testing at long range is very good advice, no other method can prove that your load works at long range other than to test it at long range. You may be able to develop a good long range load at close range but to truly test it you have to shoot it long range. If you want to know what your load will do at 1000 yards you have to test it at 1000, there is no math or formulas that can be a substitute for real world results.

 

[calgarycanada]

Thanks for the info.
I guess I should have added that experts that suggested load development at longer range did not explain 'why' part of it in detail. Lot of them believe there is something supernatural powers : between 100 and 200 yards that causes some loads to shoot good at 100 but bad at 200+ yards, one of the reasons being bullets going to sleep.
And that's why I asked on this thread, because if bullets are leaving the barrel within 1/2moa there is nothing making them go over MOA between 100 yards and 300 yards other then shooter himself, wind or ES/SD. That was my point.

Good point on ES/SD, I always do my load development through chronograph so those numbers are available to me all the time. I have used OCW method in past.
So I guess if load shoots good at 100 yards with good ES/SD it should shoot well at longer ranges if shooter is Bryan Litz (real expert)?? Or is there any other factors that change this?
The thing is, my load development range is only 200 yards and longer range is only available to me at matches. So I just wanna make sure that when I shoot crappy at longer range it's always me and not my load and/or equipment.

 

[Bryan Litz Ballistics]

So can someone please re assure me here, especially Bryan.
If a load shoots 1/2 Moa at 100 yards, theoretically it should shoot 1/2 moa upto transonic range? Of course I'm removing shooter error and wind here.

When I first started loading, lot of "experts " told me to test my loads at longer ranges(200 to 500) because what works at 100 yards may not work at 1000. But based on this thread if average dispersion of a given load is 1/2 moa it should stay 1/2 moa till it hits transonic range? So can I say it doesn't matter if I develop load at 100 or 300yards, if it groups good at short range it will group good at any range as long as shooter is upto task?

This is a good question, but to avoid derailing this thread, I've started another on bullet dispersion: http://forum.accurateshooter.com/index.php?topic=3863237.0

The intent of this thread is to plan and execute live fire testing on a 'shoot thru target' in search of converging groups.

-Bryan

 

[Joe Grad]

What are the typical manufacture focus distances for scopes w/ non-adjustable parallax? If it's say 150 yards, couldn't you shoot "loose" groups at 100yrds due to a swimming retical that looks identical to the "tight" groups at 200. Maybe the same could happen with a scope that has an adjustable parallax that isn't set correctly?

 

[Bryan Litz Ballistics]

Parallax is certainly an optical mechanism for this to happen (smaller angular groups at longer range). Typically, I think fixed parallax scopes have the parallax set for infinity.

With parallax being understood/accounted/adjusted for, some claim that bullets still fly converging flight paths.

That's what this thread and the shoot thru target is all about; to see if bullets really *do* fly like that, or not.

Parallax can certainly be a reason why many people think they do, but there are some who've claimed to manage parallax and still see the convergence.

-Bryan

 

[Joe Grad]

I figured infinity as well until i saw this...Tim O'Connor from Leupold is talking here about fixed objective scopes being set mainly to 150yds for a "standard rifle scope" ...

https://www.youtube.com/watch?v=6ziKTDIMCig


If reliable sources have adjusted for parallax errors... then trust me I'm with you. It's certainly worthy of some experimentation!!!

 

[NINERUN]

I run into guys shooting better at longer ranges often. BUT I dial the magification down from maxed out to 8-10x at 100 yds and this usually corrects it.