Who said 6BR is easy to tune?

[BoydAllen]

For ever expert, there is an equal and opposite expert...

McMillan wrote an article some years ago explaining his strategy for reading mirage refraction.

You can practice whatever floats your boat, but every variable is a variable and has an effect. Pretending one doesn't exist is just blind ignorance.

If you are saying it exists but represents a small amount of group displacement, then please articulate how you quantify the effect and compensate for it. How much in MOA do you factually compensate from one day to the next?

Or are you saying that for no reason you are aware of, your rifle shoots in different places on different days and you just aim wherever you need to to center up your groups, when you are actually unwittingly compensating for mirage refraction each time you go to the range?

Do you compete in short range group? As you have said, some use mirage and others don't. My point was that considering mirage, when you have a set of flags in front of you is obviously not a requirement for winning matches given that Tony Boyer has far and away the most Hall of Fame points shooting short range group. Personally, in the field, I have never used a scope that was high enough power to accurately access the magnitude of mirage induced target displacement, so I never have worried about it when shooting ground squirrels out to several over 300 yards. Beyond this, I have helped many improve their accuracy, virtually all to groups under a half inch, in many cases significantly under, all without consideration of mirage except for the instruction to never shoot in a "boil".

 

[Ccrider]

How much can you discern from 1 four shot group? Could be wind; could be mirage; could be scope failure; could be bag set up; could be ignition timing; could be bad Indian; could be bad arrow; could be not enough powder; could be seating depth; could be improperly formed brass.

Did I leave anything out?

 

[NorCalMikie]

Bullets stuffed .010 into the lands, starting load maybe 1.5 to 2.0 off max.
5 shot groups from the bench @ 100 yards.
Adjust powder charge up maybe 1/10th. till they all go into the same hole.
You change anything but the amount of powder and you end up chasing your tail. End of story.

 

[PracticalTactical]

all without consideration of mirage except for the instruction to never shoot in a "boil".

Again, back to the point I made earlier of using a reference scope on a tripod with a scopecam on it so you can visually see the effect of mirage moving the image of the target throughout your shot string. It does not matter what the mirage is doing at the time as long as you aim where the reference scope is pointing at that moment.

The real physical location of the target does not move, we just need to know where it really is relative to mirage refraction or mirage repositioning of the image of the target as seen from the firing point.

I am yet to see anyone but myself use a reference scope on a tripod with a scopecam, but I hope you understand what I mean by reference scope on a tripod with a scope cam, because it changes all the old school rules and provides a sense of certainty that you cannot have otherwise.

 

[BoydAllen]

Again, back to the point I made earlier of using a reference scope on a tripod with a scopecam on it so you can visually see the effect of mirage moving the image of the target throughout your shot string. It does not matter what the mirage is doing at the time as long as you aim where the reference scope is pointing at that moment.

The real physical location of the target does not move, we just need to know where it really is relative to mirage refraction or mirage repositioning of the image of the target as seen from the firing point.

I am yet to see anyone but myself use a reference scope on a tripod with a scopecam, but I hope you understand what I mean by reference scope on a tripod with a scope cam, because it changes all the old school rules and provides a sense of certainty that you cannot have otherwise.

I understand and I understood. Do you have a set of wind flags? Have you been to a sanctioned benchrest match? There is no rule that prohibits what you are doing. If they are shooting better than you, you might consider why that is, and that their method works. Mirage flow is caused by the wind. In effect mirage can be your last (in position) wind flag, but you can get the same information from flags. because the same wind that changes the flow of mirage also moves the flags. If the wind becomes strong enough mirage is blown away, but the flags will still show what the wind is doing, providing the ribbons are sufficiently heavy so as not to go horizontal and flapping, at which point differences in velocity become largely indistinguishable. In highly variable wind conditions with a setup that lends itself to being shot free recoil (no contact other than the trigger) you can actually aim when the wind has cleared the mirage and wait to shoot when it is at a lower velocity. I am not necessarily recommending that approach, but it can be done.

 

[PracticalTactical]

I understand and I understood. Do you have a set of wind flags? Have you been to a sanctioned benchrest match? There is no rule that prohibits what you are doing. If they are shooting better than you, you might consider why that is, and that their method works. Mirage flow is caused by the wind. In effect mirage can be your last (in position) wind flag, but you can get the same information from flags. because the same wind that changes the flow of mirage also moves the flags. If the wind becomes strong enough mirage is blown away, but the flags will still show what the wind is doing, providing the ribbons are sufficiently heavy so as not to go horizontal and flapping, at which point differences in velocity become largely indistinguishable. In highly variable wind conditions with a setup that lends itself to being shot free recoil (no contact other than the trigger) you can actually aim when the wind has cleared the mirage and wait to shoot when it is at a lower velocity. I am not necessarily recommending that approach, but it can be done.

Boyd,

Clearly you are convinced of your own superiority and reject anything that conflicts with your opinion even when your opinion is not based on mechanical fact.

Nothing in my post made mention of wind flags because it is not relevant to the point I'm making. My point is inside what you see with your wind flags... You have to look even closer.

You might consider that you have convinced yourself that what you do and what you have seen done for the past 40 years is the only best way it can ever be done, and to that point, you reject any notion of any new perspective that may deviate from your traditionalist bias.

If Henry Ford asked you what you wanted, clearly you would have asked for a faster horse.

Just because you are fully committed to your long standing practices does not mean that someone who looks outside your box does not have something better that can be used in addition to whatever any target shooter wants to do.

You don't have to try it, I really don't care, but don't try and elude to the point that you are out front and I'm chasing you on my point.

The target image absolutely moves due to mirage refraction and you don't really ever know where it moved from or to without what I have described.

If you just don't undusted what I'm describing, fine. If you just don't want to try it fine. Leave it at that.

 

[jimmymac]

Its has been my experience that a wind direction change will follow a mirage direction change and not the other way around.

 

[BoydAllen]

Boyd,

Clearly you are convinced of your own superiority and reject anything that conflicts with your opinion even when your opinion is not based on mechanical fact.

Nothing in my post made mention of wind flags because it is not relevant to the point I'm making. My point is inside what you see with your wind flags... You have to look even closer.

You might consider that you have convinced yourself that what you do and what you have seen done for the past 40 years is the only best way it can ever be done, and to that point, you reject any notion of any new perspective that may deviate from your traditionalist bias.

If Henry Ford asked you what you wanted, clearly you would have asked for a faster horse.

Just because you are fully committed to your long standing practices does not mean that someone who looks outside your box does not have something better that can be used in addition to whatever any target shooter wants to do.

You don't have to try it, I really don't care, but don't try and elude to the point that you are out front and I'm chasing you on my point.

The target image absolutely moves due to mirage refraction and you don't really ever know where it moved from or to without what I have described.

If you just don't undusted what I'm describing, fine. If you just don't want to try it fine. Leave it at that.

My answer was primarily to explain why I disagree with your conclusion that mirage is the main reason that people may not be able to shoot under one half inch. I used examples to illustrate my point. I have high magnification rifle scopes and have a lot of experience viewing mirage while shooting. Some very successful shooters use mirage in conjunction with flags to make judgements about where to aim and when to shoot. Others who are equally successful do not. For many years, before I had any fancy equipment, or high magnification scopes, I was able to tune my varmint caliber rifle to shoot under 1/2 inch. If being able to see mirage was a major issue, I would not have been able to do that. This is not a matter of opinion. It is a fact.

 

[Mauser06]

I'm not familiar with F class bipods....just the regular "tactical " type.


I know shoulder pressure and loading the bipod can do exactly what your target shows. You have to handle the gun consistently.

Maybe not the issue. But I can shoot vertical by varying degrees of bipod loading....I've learned how I like to shoot after some of this...I load it but not a ton. I shoot on varying surfaces..even with rubber feet, I can't load as hard off say a car hood as I can with spiked feet planted in the ground. So I load but slight. Just a nice pressure every time so I can get that same loading off aby surface I might shoot from.

 

[Dusty Stevens]

Boyd,

Clearly you are convinced of your own superiority and reject anything that conflicts with your opinion even when your opinion is not based on mechanical fact.

Nothing in my post made mention of wind flags because it is not relevant to the point I'm making. My point is inside what you see with your wind flags... You have to look even closer.

You might consider that you have convinced yourself that what you do and what you have seen done for the past 40 years is the only best way it can ever be done, and to that point, you reject any notion of any new perspective that may deviate from your traditionalist bias.

If Henry Ford asked you what you wanted, clearly you would have asked for a faster horse.

Just because you are fully committed to your long standing practices does not mean that someone who looks outside your box does not have something better that can be used in addition to whatever any target shooter wants to do.

You don't have to try it, I really don't care, but don't try and elude to the point that you are out front and I'm chasing you on my point.

The target image absolutely moves due to mirage refraction and you don't really ever know where it moved from or to without what I have described.

If you just don't undusted what I'm describing, fine. If you just don't want to try it fine. Leave it at that.

What if you set up your reference scope during a right to left steady then the mirage stops and goes to a boil or nothing? Your reference scope is wrong at that point. BR shooters have to identify whats what on the fly often keeping an eye on it while loading and putting 5 shots down in only a few seconds. Remember, we’re not trying to hit an exact point and it doesnt matter where the group forms on the legal part of the target. So if you start your group in a mirage flow that refracts your target 2” away it doesnt matter, as long as you know its still doing the same thing.

 

[PracticalTactical]

What if you set up your reference scope during a right to left steady then the mirage stops and goes to a boil or nothing? Your reference scope is wrong at that point. BR shooters have to identify whats what on the fly often keeping an eye on it while loading and putting 5 shots down in only a few seconds. Remember, we’re not trying to hit an exact point and it doesnt matter where the group forms on the legal part of the target. So if you start your group in a mirage flow that refracts your target 2” away it doesnt matter, as long as you know its still doing the same thing.

The reference scope always points to where the target was relative to the image from the firing point when you zeroed it up. That relationship remains constant no matter what else changes, or where the target image refracts.

Now regardless of where you need to hold to compensate for the effects of wind, you should always aiming for where the reticle is pointing relative to where the target image appears to be in the reference scope at the moment.

The point on the target you are trying to aim for is wherever the reference scope is pointing at that moment.

The longer you think about this, the easier it is to get your head around it and keep up with the changes in real time. I started doing this 25 years ago without the scope cam, but the scope cam makes it so much easier because the reference scope does not need to be perfectly aligned with my left eye.

I am by no means a regular 100-200 yard bench rest shooter, but the last time I did using my F Class rifle, at the end of the match, there was a bunch of regulars standing around admiring my targets on the wall, when I walked up. I said, I thought you guys were good at this, and one of the guys responded saying ya... We thought so too.

All I can say is this compensates for the old saying, lights up, sights up. This reference scope lets you see that in real time.

 

[BoydAllen]

The reference scope always points to where the target was relative to the image from the firing point when you zeroed it up. That relationship remains constant no matter what else changes, or where the target image refracts.

Now regardless of where you need to hold to compensate for the effects of wind, you should always aiming for where the reticle is pointing relative to where the target image appears to be in the reference scope at the moment.

The point on the target you are trying to aim for is wherever the reference scope is pointing at that moment.

The longer you think about this, the easier it is to get your head around it and keep up with the changes in real time. I started doing this 25 years ago without the scope cam, but the scope cam makes it so much easier because the reference scope does not need to be perfectly aligned with my left eye.

I am by no means a regular 100-200 yard bench rest shooter, but the last time I did using my F Class rifle, at the end of the match, there was a bunch of regulars standing around admiring my targets on the wall, when I walked up. I said, I thought you guys were good at this, and one of the guys responded saying ya... We thought so too.

All I can say is this compensates for the old saying, lights up, sights up. This reference scope lets you see that in real time.

Now that you have added context, for that application I can see it. I presume that you add your wind hold to your mirage offset unless you are doing the wind with your scope. Score shooters are trying to hit a specific spot and with target service delay you can only shoot so fast. For short range group we are trying to do something quite different. If conditions allow we shoot as fast as humanly possible, while glancing at 4 or5 flags before every shot. We want the smallest group. It can anywhere within the scoring rectangle.

 

[moorepower]

I will head another direction. I love N140, but at that cold of temps, the barrel is warming up and the longer the round sets in the chamber, the more the velocity comes up. A stretch, but it could be part of the issue. I have a UHMW under my bipod to let the rifle do what it wants to do, and it seems to help vertical.