ceneter hold vs. six vs. sub-six vs load

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ceneter hold vs. six vs. sub-six vs load

Post by LongSlide on Sun Aug 16, 2015 5:22 pm

Not sure if this belongs in fundamentals, equipment, or ammunition; Moderators feel free to move it to the appropriate sub-forum.

I was curious if people's experiences validate or refute the information below.  Basically, I read that some shooters can get a common zero between 25 and 50 and others can not.  I would be interested to find out what others have found on the subject.

I was reading this thread, hold dead center, which got me thinking about getting a load and sight picture that worked for both 25 and 50.  So I ran the numbers for poi at 25 and 50 using a 200gn H&G #68 with various holds (six, sub-six, and deep sub-six).  I assumed that this would be for iron sights only (what I use) and because who would use a six o'clock hold with a red dot clown ?  Other assumptions are that line of sight is 1" above bore.

I went to this site, Ballistics Calculations, to get velocity and drop measurements out to 50 yards for loads from 650 fps to 900 fps.  One of the assumptions I made was the H&G #68 had a G1 BC of 0.127, which was the only number I could find for that style of bullet.  Anyway, I computed my own drop numbers from the average velocity and found my numbers showed about 0.1" more drop at 50 yards than the ballistic calculator; I'm not sure why -- maybe there is some lift caused by the bullet's attitude or something else I'm not aware of.  I decided to use the ballistic calculator's drop numbers and then see where poi was relative to a B-8@25 and B-6@50.  I ran the numbers using the zero set for 50 yards (calculating back to 25 yards) and again with zero set at 25 yards (calculating out to 50 yards); in general, the numbers agreed, but then the math is essentially the same, so no surprise there.
 
Dead Center Hold:
A common zero is well above 900 fps.  Using my drop numbers, it's even above 1200 fps;  although, 1200 fps would get you 0.27" high at 25 if you zeroed at 50.  I wonder what 200gn@1200fps would do to your timed fire scores?

Six O'Clock Hold:
A common zero doesn't appear until above 900 fps (appears to be somewhere around 960 fps).  Doesn't really matter because I loose my front sight with this hold as my eye jumps to the bull.

Sub-Six with 1" White Under the Bull for both:
Common zero is at 805 fps +/- 15 fps.  The numbers I'm getting indicate that if you zeroed at 50, the slower you are to 805 the poi relative to the X at 25 will impact higher.  And vice versa if you zeroed at 25, slower than 805 and impact will be lower at 50.

Sub-Six with 1/2 Bull Relative to 25 and 50:
Common zero is at 750 fps +/- 20 fps.  Just to be clear, this is a sub-six hold with a sight picture with 1/2 of a bull's worth of white space.  So, for 50 yards it would be poa is 4" under the bull, while for 25 yards it would be 2.77" under.  This is what I like to do; it seems to work for me because of the relative sizes (i.e. solid angle).  Interestingly, 4.0gn Bullseye under 200gn H&G#68 gives me 750 fps at 10 feet! Smile

Deep Sub-Six with a Full Bull Relative to 25 and 50:
A common zero doesn't appear until below 650 fps (appears to be somewhere around 620 fps).  Interestingly, if your load ran 750 fps at the muzzle (4.0gn BE, like me Smile ) you would be 0.8" low at 25 if you zeroed at 50 and, conversely, you would be 1.57" high at 50 if you zeroed at 25.  This is not the load for me.

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Re: ceneter hold vs. six vs. sub-six vs load

Post by john bickar on Sun Aug 16, 2015 5:53 pm

tl;dr

Your zeroes are your zeroes. Write them in your shooting journal.

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Re: ceneter hold vs. six vs. sub-six vs load

Post by james r chapman on Sun Aug 16, 2015 7:14 pm

hmmm, I always just turned the sight up or down...

It took me years to realize what KISS meant....

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Re: ceneter hold vs. six vs. sub-six vs load

Post by LongSlide on Sun Aug 16, 2015 8:15 pm

Well, yeah, I'm all for simple.  But what's simpler than not having to adjust your sight?

As for "every zero is a personal zero", that's kind of the point of the post. I'm trying to feel out whether people have been successful at finding a common zero.  If they haven't, is there a reason?  I mean everyone, everywhere is subject to the same laws of physics.  So are there shooters that found a common zero?  

When I look at the computations, I see the numbers that represent both sets of online posters, those that do and those that don't find a common zero.  I'm just trying to find out if those computations reflect reality.

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Re: ceneter hold vs. six vs. sub-six vs load

Post by john bickar on Sun Aug 16, 2015 8:31 pm

Lemme guess: are you, by chance, an engineer?

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Re: ceneter hold vs. six vs. sub-six vs load

Post by john bickar on Sun Aug 16, 2015 9:05 pm

It does make a difference, because I've seen this about a thousand times before, and I can spot it from a mile away. No ad hominem at all.

The fundamental science of pistol shooting is psychology, not math or physics. Forget everything you think you know about learning other things, because this one is different.

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Re: ceneter hold vs. six vs. sub-six vs load

Post by john bickar on Sun Aug 16, 2015 9:20 pm

And I apologize if I come across as cranky; I am truly trying to save you some wasted effort.

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Re: ceneter hold vs. six vs. sub-six vs load

Post by jmdavis on Sun Aug 16, 2015 9:31 pm

He just might be trying to save you from going down a rabbit hole. In the end it doesn't matter what you hold or what you load. It matters what WORKS for you. 

I shoot pistol and rifle and my mentor shot pistol and rifle. It took years and repetition from a couple of national champions for one of his pieces of advice to make it through my thick Computer engineering skull. I've found that advice to be true for pistol and rifle. "You don't pick THE hold. You pick the hold that works for that day or match." If your 6 starts becoming a flat tire, adjust to your flat tire zero and the same for sub 6. With the dot it is different, but with irons, the conditions determine the hold.

Sorry if I derailed your topic further, and the idea is interesting. But will the idea make you a better shooter.


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Re: ceneter hold vs. six vs. sub-six vs load

Post by james r chapman on Sun Aug 16, 2015 9:33 pm

My understanding of your premise is you have to load to a velocity to match your zero's instead of establishing the most accurate load in your gun and dealing with the sight adjustments necessary to stay in the x ring at the variable distances.

am I close???

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Re: ceneter hold vs. six vs. sub-six vs load

Post by LongSlide on Sun Aug 16, 2015 9:36 pm

Timing is everything: this was meant in reply to John B.

Well let's chalk this up to a simple misunderstanding.  I do want to learn from the masters and clearly you have that credential.  However, I would still like to find out if others have found a common zero for 25 and 50.  If not, I would like to know that as well.

Anyone out there with a common zero for 25 and 50?


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Re: ceneter hold vs. six vs. sub-six vs load

Post by james r chapman on Sun Aug 16, 2015 9:43 pm

I believe Rob once posted that he had a common zero using different weight bullets for each yardage....

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Re: ceneter hold vs. six vs. sub-six vs load

Post by LongSlide on Sun Aug 16, 2015 9:49 pm

james r chapman wrote:My understanding of your premise is you have to load to a velocity to match your zero's instead of establishing the most accurate load in your gun and dealing with the sight adjustments necessary to stay in the x ring at the variable distances.

am I close???
Now we're talking....

To be frank, I assumed that "the load" which solved the math problem would be accurate in the pistol.  But I see your point.  If a load is not accurate, it's not accurate.  Point taken and it's a good point.

And yes, what you inferred is what I was implying, other than the "you have" to.  My premise is "why not" match the load so you don't have to adjust the sights.  Of course, notwithstanding your first point, if a load is not accurate in your gun, no math problem is going to fix that. 

Now, 4.0gn BE under 200gn is a classic, so it might not be that much of stretch to assume it could be accurate in most guns. 

Again, this is exploratory based on an idea that turned out to work mathematically.

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Re: ceneter hold vs. six vs. sub-six vs load

Post by SteveT on Sun Aug 16, 2015 9:52 pm

I never got an answer out of a ballistic calculator that explained why I have to move DOWN 4 click when I go from 25 yards to 50 yards and back up when I go back to the short line, though I didn't try that hard. I shoot a deep sub-6. 

I am an engineer but I agree with John, all the physics in the world won't help you shoot 10's. It's all in your head.

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Re: ceneter hold vs. six vs. sub-six vs load

Post by LongSlide on Sun Aug 16, 2015 10:07 pm

SteveT wrote:I never got an answer out of a ballistic calculator that explained why I have to move DOWN 4 click when I go from 25 yards to 50 yards and back up when I go back to the short line, though I didn't try that hard. I shoot a deep sub-6. 

I am an engineer but I agree with John, all the physics in the world won't help you shoot 10's. It's all in your head.
Actually the math problem I solved indicated why that might be the case.  Depending on where you zeroed (25 or 50) and what muzzle velocity and trajectory (determined by BC), you could either move up or down when moving between 25 and 50; it all depended on the particulars.  That's why I think you see so many differing accounts on the forums.

For example, with a "deep" sub-six (one full bull -- 5.54" white space below the bull) and a zero set at 25 yards, a velocity of 750 fps, I'm calculating that you'll be 1.57" high at 50 yards (assuming BC=0.127).  So, you would have to go down in clicks.  The number of clicks would vary with your velocity;  the common zero looks like it would be around 620 fps and faster velocities would result in increasing height above zero at 50.

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Re: ceneter hold vs. six vs. sub-six vs load

Post by LongSlide on Sun Aug 16, 2015 10:18 pm

jmdavis wrote:He just might be trying to save you from going down a rabbit hole. In the end it doesn't matter what you hold or what you load. It matters what WORKS for you. 
...  But will the idea make you a better shooter.
Yes, in retrospect, he probably is.  But it's just a question.  Why not ask a question and see if it pans out?

As far as making me a better shooter, I kind of think of that as being separate.  There are so many things that I could improve on that I recognize and not related to this.  But, assuming the math matches reality, it gets rid of one more thing that I have to improve on.

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Re: ceneter hold vs. six vs. sub-six vs load

Post by Rob Kovach on Sun Aug 16, 2015 11:07 pm

I did pare some of the non bullseye related back-and-forth out of this thread.

James R Chapman is correct. My lead/red dot load has 1 zero in MY gun, but it was 100% by accident. I don't make my ammo to match what my sights want, I make my loads so they give me the best score possible.

If it just so happens that your ammo that helps you score your best also has the same zero from the long to the short line, that's merely convenient. There are no awards for accomplishing this.

John Bickar is right: there is no room in the mind of a bullseye shooter for this much analysis. I'm what Lanny Basham would call "active minded". My performance pivots on whether or not I can use my shot process to drown out all of those questions about if there is a better way to get good at this sport.

For that reason I'm leaving this thread in the "fundamentals" section.

Make it easier on yourself by doing ammo development completely separately from training.

I don't recommend 2 different loads for long vs short line unless the gun really shoots better that way. I've seen more people screw up a match by showing up with only "long line" ammo or "short line" ammo, and they didn't have a zero for the other stages of the match--or their mind is convinced that they couldn't compete without the "right" stuff.

The sight screws are always with you, and screwdrivers are everywhere.

On my irons I mark the screw and sight with a metallic sharpie line that marks my "normal" 50 yard zero, and a sheet on my box says "down 3 clicks" for my current load and short line zero. I also have the number of clicks to bottoming out the sight in case I have a doubt.

I think that YOU MUST work through this question on your own until YOU are satisfied. Your mind won't be quiet enough on the firing line if you dont.

Don't be offended for being called an engineer. It's nothing disparaging. We see many engineers enter this sport, and many of them struggle with questions like yours. The inquisitiveness that makes them good engineers creates a lot of obstacles that makes it hard for them to succeed until they work through all of the things they have been wondering about.

Does that make sense?

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Re: ceneter hold vs. six vs. sub-six vs load

Post by C.Perkins on Mon Aug 17, 2015 5:52 pm

I do not know if I am answering your question but will tell you what I see while shooting my pistols with their respective loads.

Iron sights with Beretta 92FS for EIC matches:
 Line of white at 50yds.
 Sub 6 at 25yds.
 No sight adjustment.

Iron sight with Ruger GP100 for D.R.:
 Line of white at 50yds.
 Sub 6 at 25yds.
 No sight adjustment.

Red dot on .22 Marvel conversion, .38 M52-1, .45 Clark long slide.
No sight adjustment between long and short lines.

There may be a sight adjustment on certain days because of weather and sun position at the long line but falls into place going to the short line.

With some experimentation, you can change point of impact by moving your left foot position(I am right handed) but that is another subject which can get a bit long.
I can move my point of impact left, right, up or down when needed and not touch the sights.

YMMV

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Re: ceneter hold vs. six vs. sub-six vs load

Post by LongSlide on Mon Aug 17, 2015 6:48 pm

Yes you did and thanks.  So for the Marvel, M52, and Clark, do you adjust your hold like you did for the Ruger and Beretta?

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Re: ceneter hold vs. six vs. sub-six vs load

Post by C.Perkins on Mon Aug 17, 2015 8:09 pm

LongSlide wrote:Yes you did and thanks.  So for the Marvel, M52, and Clark, do you adjust your hold like you did for the Ruger and Beretta?

The Marvel, M52 and Clark wear red dots.
So no adjust hold/aim as with iron sights.

Using a red dot.
If I look at my targets from the long line, the hits are usually center to 6' oclock.
My hits on target at the short line are usually center and maybe a bit toward 12'oclock.
We have a 10 ring around 3 and a third inches.
I try to keep it as simple as I can without trying to adjust the sights for that exact dead center X.(Too much crap going through my head, just as well adjust my left foot).
I cannot hold that good and accept my wobble to be 10 ring and not X ring.
To be honest on my best days, my wobble is 9 ring.(I am not a high master Smile
If I can shoot into the 10 ring at 50 and 25 yds  all is good.
I am not going to worry about the 1.5" variable between the two distances cause I have a hair over 3" to work with.

Many will not make sense of what I speak.
Does not matter.
It works for me.

That is the bottom line.
It works for me.

Find what works for you.

Clarence

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Re: ceneter hold vs. six vs. sub-six vs load

Post by DavidR on Tue Aug 18, 2015 11:07 am

The Problem of proper zero can be easily solved by using the proper tool. Laughing  


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Re: ceneter hold vs. six vs. sub-six vs load

Post by jmdavis on Tue Aug 18, 2015 12:06 pm

I thought that the proper tool was a swiss army knife.

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Re: ceneter hold vs. six vs. sub-six vs load

Post by LongSlide on Tue Aug 18, 2015 6:40 pm

DavidR wrote:The Problem of proper zero can be easily solved by using the proper tool. Laughing  

Smile  Or no tools at all. Razz

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Re: ceneter hold vs. six vs. sub-six vs load

Post by LenV on Tue Aug 18, 2015 7:24 pm

  Or no tools at all.

I am afraid I have bad news. If you find that perfect sweet spot you are looking for it will never last. The bullet may have the same zero for 25 that it does at 50. It may be the most accurate load for your pistol that you have ever found. But...The pistol won't be zeroed when you shoot it in a match. The light will be different or the altitude is different. Even outside temperature is different. Your adrenal levels could be skyrocketing and your grip is different. My point is...don't forget the screwdriver.

Len ( pretty much all of that has happened one time or another to me. I've even forgot the screwdriver)

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Re: ceneter hold vs. six vs. sub-six vs load

Post by LongSlide on Tue Aug 18, 2015 8:34 pm

You just watch Len, I'll get that perfect zero and shoot a 100!  With 10 X's!  You just wait and see!



Point taken Len.

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Re: ceneter hold vs. six vs. sub-six vs load

Post by jmdavis on Wed Aug 19, 2015 10:27 am

Zins said he just "puts the dot on the X and breaks the shot without the gun moving." 

I found that if I quiet my mind, put the dot on the X and break the shot without the gun moving, I do much better. If you can do that, you will find yourself shooting 100's and 100's with 10x. 

But you have to believe that you can do it and you have to stop thinking during shooting.  I don't know a lot about bullseye, but I know that much.

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Re: ceneter hold vs. six vs. sub-six vs load

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