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When a zero is not really a zero


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I often hear people saying their rifle is zeroed "x number of inches high at 100 yards".

 

Surely this is not a zero at all ?

 

I took a guy out stalking who missed an easy shot at 250 yards. I asked him about his zero and got the above reply. I asked him about what range his poa and poi coincided and he was not sure.

 

In my book, a rifle is zeroed at a particular range when poi and poa are same and turret is at "0" hence the term "zeroed" ?

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One reason that you might adjust your sights 'x number of inches high at 100 yards' would be so that the actual zero is set for the 'maximum point blank range'. It clearly didn't work for your fellow stalker though!

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I often hear people saying their rifle is zeroed "x number of inches high at 100 yards".

 

Surely this is not a zero at all ?

 

I took a guy out stalking who missed an easy shot at 250 yards. I asked him about his zero and got the above reply. I asked him about what range his poa and poi coincided and he was not sure.

 

In my book, a rifle is zeroed at a particular range when poi and poa are same and turret is at "0" hence the term "zeroed" ?

I disagree. I have 'zeroed' rifles to strike 1 inch high at 100 yards for very nearly 50 years. It's a simple way to set up a stalking rifle without blinding the operator with science. It's disappointing that your guy didn't know anything about his bullet trajectory, but unfortunately not unusual.

 

Keep in mind it's very hard for stalkers to find places to practice/check zero safely. Finding a spot where one can shoot safely at 100 yds is a compromise. Ideally the stalker should shoot his rifle at the maximum range he is going to shoot at in an emergency situation and lots of different shorter ranges. Very few urban based folk have access to facilities to do this.

 

Without ranges, competitions and tests for stalkers, standards aren't going to improve.

 

Regards

 

JCS

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Correct.

The common practice is to "zero" at 100yards for convenience.1.5 inches high.

This is in acordance with many cartridge loadings which if sighted to be 1.5 inches high at 100y, will then be fairly close to 'proper zero' - ie POA=POI at around 200y,for many normal sporting loadings. Likewise, though,striking low by at least 6 inches -and more -by 300y-it becomes quite variable with cartridge/loading-but very little beats 6",and nothing 5"....see below for examples.

It is of course important,as you say,to know the true zero,and probably the individual load drop at 300 (or further if such shots are to be taken.)

A clear miss at 250 yards suggests an additional error in the shooting or shooting solution-but depending on cartridge loading,the margin for error is reducing with range beyond 225 ish... Many 6.5x55 commercial loadings are lightish with 140g,and could be 9 inches low at 300,so pretty marginal an small deer at 250 without proper correction,and 100g 243 commercial may well be 8 inches drop,and the good 6.5s 7+ inches.....all with a proper 200 zero or less reliable 1.5 " high at 100y (less reliable esp if the 3 shot "group" at 100 yards is an inch or more....centre is ...where,exactly ?

 

gbal

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I zero everything at 100 and dial or use the FFP scope's mill dot ret and know my drop with distance. No excuse for anyone these days, given all the apps and info available not to know their bullet's trajectory. Such people ought to question themselves as to whether they ought to be out with a centrefire rifle at all if they don't know where it's POI is with distance.

 

I can see the point in a simple set up with Duplex ret zeroing to MPBR, with the spread of shots limited to average group size plus drop being within the kill zone. That then gives a maximum range which can be shot "point blank" and with the use of a rangefinder to double check, it's simply point and shoot. Anything beyond that should be left alone or stalk in closer if you don't have time to dial or know how far above to hold over. That's all before we get into wind allowance which starts to become important much beyond 150 to 200 yards.

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Zero can be anything you want it to be

For example dead on in the Centre at 100 prone, 2 mins up and 2 mins left at 200 if sitting and slung up but no windage on if prone once again, but as you may be shooting with a cant at given distances in different positions, then you may have to apply windage

 

The 1" high must have some relevance somewhere, but I'm not sure where

 

Your average stalker who has to pay for a days shooting has nowhere near the experience of someone who has their own piece of land to shoot on, or a target shooter who competes or practices regularly, knows what his bullet does, can range, is steadier in position, can shoot from more than one position and can and will also own up when he makes an error.

Furthermore, your man may not be a great shot (I know that's hard to believe as everyone is the best shot ever, especially me)

 

The answer in my mind is practice, lots of practice, a bit more practice, a scope that dials and a bit of experience with ranging

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I can see the logic in this method - my point is the rifle is not "zeroed" unless poi and poa coincide.

Some people only have access to a 100 yard range for zeroing, this means by your method the only option they have is to zero at 100, not always the best! Also a 250 yard shot may well not be 'easy' for a lot of shooters under field conditions.

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The answer on my mind is practice, lots of practice, a bit more practice...

 

I agree practice is essential and I never do enough, but it needs to be complemented with competition and stalking. Then the results of all three elements need to be reviewed.

 

Regards JCS

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Mark,my post 6 gives reason for the 1'-though betterperhaps 1.5 inch high POI above POA ( but Zero range is where POI/POA coincide,in usual ballistic speak.) To repeat:

 

It's pragmatic (if that counts as 'relevance')- for the reason(s) I gave- POI 1.5 inch at 100y high above POA will mean a true zero at close to 200y for a wide range of cartridge loadings. And that was deemed acceptable for most field shooting at creatures larger than mice.

AND for your other reasons- 1) by no means everyone has any/ready access to a longer 'zeroing' range 2) not everyone can shoot well enough to make 200+ shooting very meaningful 3) tempting to add that some will simply be ignorant on even the basic performance parameters of their once a year rifle. So damage limitation to 200y for field shooting...probably around/longer than the modal shot distance for much-but not all - such field shooting.

It's actually not at all poor for most field shooting-or short range targeting (esp given sighters).223-308 for example fall in the 'within kill zone' to around 200-250 yards-though of course,this assumes shooting skill isn't much worse-as must any alternative).

 

PRAGMATIC,then for a variety of reasons,coincident with the practice- 1-1.5" high will "do" for a lot of shooting out to 250y...always assuming rather modest shooting skills/rigs/knowhow and carehow... Without which...well,it's a mess every which way...hero to zero?

 

As Tom Lehrer sang it "I shot the maximum the game laws would allow-two game wardens,four hunters and a great big Jersey cow".

 

gbal

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I often hear people saying their rifle is zeroed "x number of inches high at 100 yards".

Surely this is not a zero at all ?

I think l might know whose post prompted yours...

 

;-)

 

As l stated in my post, l am a small scale stalker. I don't risk wounding an animal by trying to shoot beyond my limitations. My intention is to make my rifle/scope combo a "point & click" interface to the best of my ability.

 

Zeroed as described, my bullets are dead on at 35 and 190 yards, and at no point are they more than 2" above or below point of aim until 230 yards, which is beyond the maximum range at which l will shoot at a living creature.

 

K.I.S.S.

 

maximus otter

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I agree practice is essential and I never do enough, but it needs to be complemented with competition and stalking. Then the results of all three elements need to be reviewed.

 

Regards JCS

Precisely

 

And you also have the occasional stalker etc who "only zeroed the rifle last September, and I haven't used it since then"!!!

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Mark,my post 6 gives reason for the 1'-though betterperhaps 1.5 inch high POI above POA ( but Zero range is where POI/POA coincide,in usual ballistic speak.) To repeat:

 

It's pragmatic (if that counts as 'relevance')- for the reason(s) I gave- POI 1.5 inch at 100y high above POA will mean a true zero at close to 200y for a wide range of cartridge loadings. And that was deemed acceptable for most field shooting at creatures larger than mice.

AND for your other reasons- 1) by no means everyone has any/ready access to a longer 'zeroing' range 2) not everyone can shoot well enough to make 200+ shooting very meaningful 3) tempting to add that some will simply be ignorant on even the basic performance parameters of their once a year rifle. So damage limitation to 200y for field shooting...probably around/longer than the modal shot distance for much-but not all - such field shooting.

It's actually not at all poor for most field shooting-or short range targeting (esp given sighters).223-308 for example fall in the 'within kill zone' to around 200-250 yards-though of course,this assumes shooting skill isn't much worse-as must any alternative).

 

PRAGMATIC,then for a variety of reasons,coincident with the practice- 1-1.5" high will "do" for a lot of shooting out to 250y...always assuming rather modest shooting skills/rigs/knowhow and carehow... Without which...well,it's a mess every which way...hero to zero?

 

As Tom Lehrer sang it "I shot the maximum the game laws would allow-two game wardens,four hunters and a great big Jersey cow".

 

gbal

Don't agree with the first part

 

Zero is whatever you want it to be, POI/POA isn't always relevant

 

When I shoot at 100yds to "zero" POI/POA do coincide (more or less) but when I shoot the Urban Contact Match, I aim 2" or so lower at 100 yds when shooting off a post....because that's my zero

 

Shooting CSR teaches you a lot. We shoot (and zero) at all distances from 100-600yds, and we also shoot from 100 down to 25yds

 

What that teaches us about zeroes and crossovers is that :-

100 standing against a post and 75 kneeling around a wall are the same

50 and 200 are the same

25 and 300 are the same

 

200 prone is different from 200 sitting and If I can do all that with acceptable accuracy, then why do I, and many others, have such trouble putting all 10 shots on a Fig 12c or Fig 14 Window target (approx 12"x12" in 3 second standing/kneeling snaps at 100yds?

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Mark,and he's using a different make/bullet etc this year,as his buddy wasted the last two of their shared box of ten on follow up,shots. The new box "was much cheaper,though...and they are FMJ-Full Magnum Jagdt ...that's German for 'Hunting' you know-should be good."

 

Achtung!

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I have a 100 yard range at the back of the house so I regularly check accuracy a100 yards. Also a lot of what I shoot ( and I suspect many others too) is 100 yards. When testing group size 100 yard is the go to. So you can see where the x high at 100 comes from

 

However I do know I get zero at 50, 1in high at 100, zero at 170 yards. 1 in low at 190 that's the preferred range I like to operate in.

 

I test at the other ranges but I am regularly checking at 100. So I am 1 in high at 100 with a 170 yard zero.

 

250ysrd at a small deer is long enough for many. The skill is putting clients at ease where they are happy to man up and to say sorry " that's a bit too much of a shot for me"

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Oh one thing that comes to mind is I have had with factory ammo what I can only describe as a duff round. I was shooting my 100 yard target nice constant 3 shot groups then one never hit. No strike on the large 4 ft back stop sheet and no splash from the heap of soil behind ? think if I remember correctly the sound of the round was not quite right either

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I have a 100 yard range at the back of the house so I regularly check accuracy a100 yards. Also a lot of what I shoot ( and I suspect many others too) is 100 yards. When testing group size 100 yard is the go to. So you can see where the x high at 100 comes from

 

However I do know I get zero at 50, 1in high at 100, zero at 170 yards. 1 in low at 190 that's the preferred range I like to operate in.

 

I test at the other ranges but I am regularly checking at 100. So I am 1 in high at 100 with a 170 yard zero.

 

250ysrd at a small deer is long enough for many. The skill is putting clients at ease where they are happy to man up and to say sorry " that's a bit too much of a shot for me"

 

Spot on. Common sense prevails.

 

I think that target shooters and stalkers have different needs. Stalking is more about limiting the distance but having the ability to take a quick shot being sure that it will hit the kill zone. Target shooting demands greater precision, consequently there's not really a right or wrong answer here, just what's fit for purpose. Bradders point is not lost though. That's more about HOW the rifle is zeroed, as this affects POI depending on how the shot in the field is taken. I've shot enough off sticks, offhand and kneeling to know that there is a difference in POI and that will vary with each shooter/rifle combination so practice is the key.

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I can see the logic in this method - my point is the rifle is not "zeroed" unless poi and poa coincide.

 

I would look at it this way:

To 'zero' is to set the sight so that the elevation and wind scales read 'zero'. You can do that at whatever range you want, and with whatever POI you want relative to the POA.

 

I have some sympathy with your guest-Rifle - my .270 is zeroed about 1.75" high at 100yds. This means I hold 'on' out to 200yds, a couple of inches high at 250yds and (should it exceptionally be necessary) 8" high at 300yds.

 

I've no idea where the POI and the POA coincide - probably about 200yds - but that doesn't really matter too much.

 

As far as dialling in goes, for deer at ordinary stalking ranges it seems like an unneccessary complication. For me, maximum point-blank range zero, and known holdovers thereafter.

 

I can't say I've noticed dfferent POI from different position. Possibly, this is because the differences are within the limits of my overall shooting ability (which I'de describe as unremarkable) - but I do try to hold the rifle as far as poss the same in all positions - maintaining a grip on the forend even when prone off a bipod.

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I would look at it this way:

To 'zero' is to set the sight so that the elevation and wind scales read 'zero'. You can do that at whatever range you want, and with whatever POI you want relative to the POA.

 

I have some sympathy with your guest-Rifle - my .270 is zeroed about 1.75" high at 100yds. This means I hold 'on' out to 200yds, a couple of inches high at 250yds and (should it exceptionally be necessary) 8" high at 300yds.

 

I've no idea where the POI and the POA coincide - probably about 200yds - but that doesn't really matter too much.

 

As far as dialling in goes, for deer at ordinary stalking ranges it seems like an unneccessary complication. For me, maximum point-blank range zero, and known holdovers thereafter.

 

I can't say I've noticed dfferent POI from different position. Possibly, this is because the differences are within the limits of my overall shooting ability (which I'de describe as unremarkable) - but I do try to hold the rifle as far as poss the same in all positions - maintaining a grip on the forend even when prone off a bipod.

 

If you get the chance, it's an interesting exercise to aim three shots into a 2 inch circle from prone, off sticks, kneeling and perhaps sitting. As people generally use slightly different grips/rests for each position, it may well affect POI (it does with my rifle), although I try and keep crosshairs as level as possible (ie no cant).

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I think l might know whose post prompted yours...

;-)

As l stated in my post, l am a small scale stalker. I don't risk wounding an animal by trying to shoot beyond my limitations. My intention is to make my rifle/scope combo a "point & click" interface to the best of my ability.

Zeroed as described, my bullets are dead on at 35 and 190 yards, and at no point are they more than 2" above or below point of aim until 230 yards, which is beyond the maximum range at which l will shoot at a living creature.

K.I.S.S.

maximus otter

As I said, I understand the logic of "point blank" range etc.

 

Its just that zero is something else. Its poi and poa alligned when elevation and windage settings are at zero. The hint is in the word ZERO.

 

A shooter might have a rifle which when sights set at 200 shoots 2" high and 2" right. Just because he knows this and aims 2"low and 2" left does not mean his rifle is zeroed !

 

As to easy shots - it was a fallow deer stationary on a stubble field. Shooter prone with rifle rested. No rain. No wind.

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From a previous post.......

 

"I've no idea where the POI and the POA coincide - probably about 200yds - but that doesn't really matter too much"

 

This is just the point ! If you do not know the precise range poi and poa coincide, how can you say your rifle is zeroed ?

 

Zero means poi and poa coinciding at a known range. The rifle can then be said to be zeroed at THAT range. Shooting high at 100 yards is not a zero !

 

Edit - I know I am being pedantic - its just one of those sayings that I always notice. Like BULLETS v HEADS for some folks :-)

 

Obviously the main thing is knowing where your round goes, even if its high etc - all cool as long as it works for you.

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