Sighting 30-06 4" high at 100 or 320 yard zero for deer

I wounder what if any drop there is from shooting in the cold, it's one of the reasons I was told to be high when sighted in.

Stevel said:

Thanks for all the replies. This situation is for an open space rifle in 30-06. For woods hunting I use a rifle zeroed at 100.

For the times I hunt open fields I sight in 2.5" high at 100. Some of my rifles have an inch+ shift between cold bore and hot which has caused me to hit high (once), but it still dropped right there. Add in temp differential and you can get another inch plus of deviation.

I've never shot a deer past 200 yards and doubt I will. But the situation had me thinking: if I sight in for mpbr at +2.5" with a warm gun, the cold bore could be +3.5" to +4.0". Even if the gun is shooting a little high, it still places me in the vitals out to a farther distance than I would take game.

If mpbr for a whitetail with an 8" vital zone, though I think 6" is a better figure to use, isn't it more difficult to judge mpbr and cold bore adjustment together? What if you are shooting past mpbr? Then you need to estimate a holdover.

Wouldn't it be more repeatable to set your maximum rise close to the 6" and aim at the lowest vital spot (the heart)? Well yes it would.

If you are 30-300 yards having a consistent point of aim just behind the front leg would put the bullet placement at the heart or lungs and help the shooter with consistency.

Like most things in hunting, people have things that work for them. Sometimes ideas look great at first but others have reasons they may not be so great.

Thanks again for the replies.

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I always sight my hunting rifles using cold bore shots. It's kind of unfair, but I can shoot to 520yds off my back porch. Rifles that shift much from cold bore to shot number 3 don't make it to the woods. If it takes more than 2 shots, I failed as a hunter.
I think you're definitely on the right track with 2.5 high.

Stevel said:

Thanks for the reply. The point of the technique is that you have the same point of aim, which is the heart. The bullet will then hit anywhere from point of aim to +5.7" which still has you through the lungs.

It actually takes away the need to hold over unless you are out past 320 yards. In which case I will hold off shooting. Others may not.

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I see. I either break their neck, or shoot high shoulder. It's more a difference of aim point to yours.

My .308 is sighted in at 2.75” high at 100 which gives me a 6” target MPBR out to 265 yards and my zeros are at 24/226 yards. 150gr interlocks at 2,740 FPS average.

troy fairweather said:

I wounder what if any drop there is from shooting in the cold, it's one of the reasons I was told to be high when sighted in.

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I have fired across the course matches in the snow. It was miserable. I was miserable. My zero's were different, and I think it was more due to the fact that my hands were cold, my glasses were fogging up, I was wearing a huge amount of clothing that stiffened me up, and changed my stock weld.

And, having shot in extreme heat, I can't tell much of a change in elevation because I can't get my heart rate down low enough to shoot a group!

Someday in the future, when all shooting will be electronic and humans won't be holding weapons or pulling triggers, maybe the stressful affects of extreme weather will only be seen in the ammunition, and not in the shooter. But until then, weather extremes affect the human more than the weapon.

Stevel said:

You know, I had boss once who said the dumber someone is, the dumber they think everyone else is.



Well actually I have, but that's not the topic of the post. The topic is whether others have.



Second, the calculation would actually be setting the crosshairs LOWER, so the impact would be a little higher. Holding the crosshairs high would produce a higher impact.



Where did I say I was going to try a theory by taking a shot at a deer? You presumed that and then transferred your assumption into a real or proposed action by me.

Then thought you'd insult me because I hadn't lived up to your imagination (or hallucination)

I usually don't respond to stupid because it just leads to more, but yours hit me at just the right time and place.

Btw, after testing it worked REALLY well on the fellow below. I was just wondering if it was a technique anyone else had used and wrote the question in such a way as to hold stupid responses bay. My bad for thinking stupid wouldn't crash the party anyway.

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Nice shot.

I've shot a couple or three before myself.
https://www.glocktalk.com/media/head-shot.10582/full

Slamfire said:

I have fired across the course matches in the snow. It was miserable. I was miserable. My zero's were different, and I think it was more due to the fact that my hands were cold, my glasses were fogging up, I was wearing a huge amount of clothing that stiffened me up, and changed my stock weld.

And, having shot in extreme heat, I can't tell much of a change in elevation because I can't get my heart rate down low enough to shoot a group!

Someday in the future, when all shooting will be electronic and humans won't be holding weapons or pulling triggers, maybe the stressful affects of extreme weather will only be seen in the ammunition, and not in the shooter. But until then, weather extremes affect the human more than the weapon.

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If I get a chronograph I'll do some tests. I've had it 20 below when hunting.

troy fairweather said:

If I get a chronograph I'll do some tests. I've had it 20 below when hunting.

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Here's a quick article on the topic from American Hunter.

https://www.americanhunter.org/articles/2013/6/28/how-much-does-temperature-effect-bullet-impact/

They did not address how the cold affects the powder,

I think some guys give there selfs to much credit on how they can range a animal.

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I think there are lots of different kinds of hunting. I have hunted places where one couldn’t shoot 100 yards without the bullet hitting something. Other places where you could see so far, your bullet couldn’t make it there.

At our place, most often you are hunting from a blind or it’s night time makes it simple for “new” guys/gals, no problem with 100 yd zero. The odds are much greater that I might need a quick shot close than not have time to figure out the distance of a far away animal.

Some of the little guys I have shot on the run would have been instinctively missed if I were sighted in 4” high at 100. Like this little guy running away.

Stevel said:

..., theory is you can aim at the heart for shots out to 320 yards and place it in the vitals. Similar to Maximum Point Blank Range, but allowing greater distance with dead on hold with smaller vital zone variance.

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The practice goes back, from what I understand, to the era when the vast majority of optics were sighted in at the range, and no adjustment was done in the field, nor were reticles available for various systems of "hold over", unless one actually had use of a scope manufactured for sniper use. The time when the Weaver and Redfield 4x scopes were the standard, and both came with simple crosshairs. The reason was the cost of more complicated scopes and the fact that a lot of the hunting population trained with iron sights, started hunting with iron sights, and range estimation was something most hunters were poor at (many are today as well). So the cost of such complicated scopes wasn't justified to the majority of hunters using them.

So in your proposed method, you have a rather high impact at 100 yards, but dead-on at 300-320 yards.

In the older method, the rifle is sighted in many cases (and mentioned in some of the replies) with a zero at 200 yards, thus giving a slightly high impact at 100, and a slightly low impact at 300, with about the same variation as the 100 yard impact was high. This was how I was taught to sight in a basic sporting scope on a hunting rifle.

The second method seems to give a bit more room for error at 100 yards than does the first. It may not actually give any advantage, but allowing for both high and low impact error to some hunters seems the better of the two options.

As I mentioned, technique #2 is very similar to how one sights in a rifle with iron sights for 100 zero with say a carbine using a pistol cartridge such as .357 magnum or .44 magnum. Persons using such rifles know that they will see the deer well enough to shoot the vital area, under 100 yards, so all they need is get a good sight picture on that area, and squeeze-off the shot.

The same idea for both scope zeroing methods, but of course with modern cartridges the distances are far greater. Bottom line if it allows you to make a clean, human harvest, whichever works for you is the best idea for you.





LD

Slightly more complicated than the above, you can’t be zeroed at the muzzle.

It will be more like this.



or at the one range at the peak of the arch.

Where I set up my blind is next to our range, the steel is up at 100, 200 and 300 yrds so I have a known distance, that is my theory on sighting in at 200, when I set up i have been known to set in the truck with the heater running step out and use a shotgun. When hunting over the garden it is less than 100yrds to the treeline from the fallen in shed so the shotguns or black powder guns get the nod, I set with my grandson there when he goes with me and his mini 14 is dead on at 80yrds when shooting from a saw horse.
I would think 6" difference would need holdover to be considered a good shot on deer it might still get the job done but I like having a little room for error

Jack Ryan said:

Pretty close is for people who hunt pie plates and like to blood trail stuff

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Back in the early 60's when I first started to hunt deer, a 9" pie plate was the standard for a deer's vitals, whether it was for a gun or a bow. The idea was, if you could consistently hit that pie plate from whatever distance you intended to take a shot, your blood trail would be short. That was back in the day when the norm for deer was an open sighted 30-30 or a 50# recurve bow. This was back in the day when one would openly brag about a 150 yard shot with said 30-30 or a 35 yard shot with said recurve. Convince me if I'm wrong, Jack Ryan, but I'd be very hard pressed to think that standard does not still apply today. The same principle applies today as it did half a century ago, aim appropriately for the POI to be as close to center of said 9" pie plate "kill zone" as possible. Just like 50 years ago, if that 9" kill zone is applied over the boiler room of a deer size target, hitting it, will indeed, result in a dead animal, in a very short amount of time. Blood trailing may or may not be necessary.

I myself enjoy blood trailing. It was something taught to me half a century ago by my mentors and honed over the years by necessity. But I do not shoot with the intent so I can blood trail, but it is something I know will have to be done, and done right, at some point in time, regardless of folks that claim otherwise. Ain't nuttin' more satisfying than finding a dead animal at the end of a tough and frustrating blood trail, that someone previously thought was an irretrievable animal. IMHO, blood trailing and tracking skills are just as important as shooting proficiently. Wind, branches, grass, adrenaline, nerves or just a random pulled shot can all lead to a POI outside of that "pie plate". Far too many folks spend all their time practicing their shooting skills, while completely forgetting about woodsmanship skills like blood trailing and tracking.

As for the zeroing of my scopes, I try to keep the zero as close to where I think the majority of my shots are going to be at. Over the years I've found that those times when you have to react quickly to get a good shot off, are those times when you are going to forget to hold high or hold low. You put the sights on the spot you want to hit and pull the trigger. Most of the time, those opportunities present themselves at close range or within a range that you are used to. Deer way outside of the range you are used to shooting at(such as 300+ yards compared to under 200) give you more time to think and compensate. Because this is something you know is outside your norm, you remember you have to hold high. If I am to error on the zero, I prefer to error on the side of hitting high. Breaking the shoulders, hitting the artery under the spine or the spine itself are much better alternatives and will result in more retrieved deer than a shot low on the brisket or into the legs. In the last dozen years or so, I have used open sighted revolvers for my primary deer firearms. My sights are set for the max distance I would take a shot with each specific caliber. Anything short of that, with each specific caliber, is still in the boiler room.

troy fairweather said:

If I get a chronograph I'll do some tests. I've had it 20 below when hunting.

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The batteries on my chrony crap out when temperatures are in the 40's. I have kept them on the dash, to warm them up, and I have kept them in my pocket prior to loading them in the chronograph, and that helped. I am curious if someone has a chronograph that functions down to zero degrees.

Anyone in the woods at minus 20 risks turning into a Popsicle. I would stay inside where it is nice an warm.

Slamfire said:

The batteries on my chrony crap out when temperatures are in the 40's. I have kept them on the dash, to warm them up, and I have kept them in my pocket prior to loading them in the chronograph, and that helped. I am curious if someone has a chronograph that functions down to zero degrees.

Anyone in the woods at minus 20 risks turning into a Popsicle. I would stay inside where it is nice an warm.

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Could also put some ammo in the freezer, I know the air is not cold but your only shooting feet.

jmorris said:

Slightly more complicated than the above, you can’t be zeroed at the muzzle.

It will be more like this.

View attachment 869753

or at the one range at the peak of the arch.

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That's what I was talking about back up-thread.

jmorris said:

Slightly more complicated than the above, you can’t be zeroed at the muzzle

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Neither can the iron sights.
The illustration was not to scale, but was and is merely to lend understanding to what is happening with the two, distant points used as a zero.
I never suggested it was an accurate, graphic representation of what is actually going on between the relationship of the scope's line of sight perspective, and the actual flight path of the bullet. Sorry if you thought my simplistic illustration was confusing.

LD

Not confusing to me but I too like to lend understanding too. One also won’t always have two points of zero either.

Most missed shots are high. People tend to overestimate how far away the animal is. I think anything over 2 inches at 100 is asking for shots over the back.