# Having to sight in a rifle at 25 yards, help



## bwsmith

Alright.  One day of hunting left where I am going.  My crappy scope died and mounted a new one.  I can't get to Creekside today because of the ice.  I am going to have to hit Nicks and get it zeroed at 25 yards until I can get to an outdoor range at 100.  It should at least get me pretty good on left and right.  I am shooting a 308.  How far above bullseye should I be zeroing it to get me close at 100 yards?

Also, it looks like I will have to leave early Friday morning to get to the land Friday afternoon.  Any decent range on the way from Atlanta to Dooly County?  Or is there a decent rifle range in driving distance that is open on Sundays (Creekside and Advanced areboth closed Sundays)?

Talk about cramming!  uggh.


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## Jeff Phillips

Zero dead on at 25 and limit your shots to 75 yards.


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## Dead Eye Eddy

.308 is comparable to .270.  I sight my .270 in 1" low at 25 yards.  I've killed deer from 20 yards to 250 yards with a dead on hold.  It's about 2.5" high at 100.  Don't sight it in high at 25, because you could miss a deer high at around 100-150 before the bullet starts dropping again.


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## WTM45

Like Eddy said, 1/2" to 1" low at 25y will have you closer to a 100y zero.  But you will still be high at 100y.  You have to verify it by shooting at that distance.
There are too many variables, scope height (line of sight) to bore is but one.  Each rifle shoots differently.

EXACT at 25y is important, as 1/4" at 25y is 1" at 100y or 2" at 200y.  Get those shots where you want them on the paper at 25y, and drop them on top of each other.
Verify at distances as soon as you can.
Until then, greatly limiting your shot distances is recommended.


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## bwsmith

I'm confused. If it is 2.5" high at 190, then why wouldn't you zero 2.5" low at 25?


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## WTM45

bwsmith said:


> I'm confused. If it is 2.5" high at 190, then why wouldn't you zero 2.5" low at 25?



Think of it as a cone coming out of the muzzle.
Little movements at close range result in much greater movement at longer ranges.
Minute of Angle.

1/4" at 25y = 1" at 100y = 2" at 200y = 3" at 300y.

So you have to be VERY PRECISE when shooting at 25y as it is magnified at longer distances.


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## bwsmith

I may have misunderstood.  Is sighting it in at 1" low at 25 yards going to be fairly close to zero at 100 yard or is it going to be 2.5" high at 100?  I see on the box of ammo that it has +2" listed at 100 yards and 0 at 200.  I understand that increasing rate of difference at greater distances but I may have just read that wrong as far as 2.5" high.


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## jkoch

Like Eddie said, If you zero it 1" low at 25 yds you can hold on you target out to sbout 200 yds. You will be about 1 1/2' high at 100.


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## bearpugh

yup, a lil low at 25. with my .06, if i sight 1" high at 100 yds will print about 1/2 in low at 25. thats with 150 grn core loks.


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## tsknmcn

.7" low @ 25 yards with a 150gr bullet
.6" low @ 25 yards with a 180gr bullet

assuming 1.5" sight height.


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## Davans

Both my 270WSM and my 7MM-08 are about.
1.5 low @ 25yds.
1.5 high @ 100yds
Zero @ 200yds


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## dawg2

WTM45 said:


> Think of it as a cone coming out of the muzzle.
> Little movements at close range result in much greater movement at longer ranges.
> Minute of Angle.
> 
> 1/4" at 25y = 1" at 100y = 2" at 200y = 3" at 300y.
> 
> So you have to be VERY PRECISE when shooting at 25y as it is magnified at longer distances.



A very good illustration of this effect can be done with a laser pointer or laser sight (esepecially if it is a little dark outside).

Shine your laser and hold it on a tree trunk (or target) at 25 yards.  Then pick a tree trunk at 100 and TRY to do the same.  Small movements are magnified at distance.


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## Dead Eye Eddy

I have a 50mm scope, so my line of sight is a little higher than with a 40mm scope.  As stated earlier, my .270 is 1" low at 25 and 2.5" high at 100.  If you sight your .308 in 1" low at 25 yards, you will be able to hold your scope on the shoulder/lungs out to 250 yards or so and make a killing shot.  Your bullet won't rise or fall more than about 4" from center anywhere in that distance.


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## awr72

im not tryin to start anything but a bullet never rise just falls from point of aim i think i would say 2inches high . my thinking is this if a bullet never rise at 1inch low it would be lower at 100yard and beyond maybe im incorrect,please correct if i am


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## bearpugh

awr72 said:


> im not tryin to start anything but a bullet never rise just falls from point of aim i think i would say 2inches high . my thinking is this if a bullet never rise at 1inch low it would be lower at 100yard and beyond maybe im incorrect,please correct if i am



do that and you'll be way high at 100.


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## bwsmith

awr72 said:


> im not tryin to start anything but a bullet never rise just falls from point of aim i think i would say 2inches high . my thinking is this if a bullet never rise at 1inch low it would be lower at 100yard and beyond maybe im incorrect,please correct if i am


I am pretty sure they actually do rise out of the barrel.  A 308, as far as I know, hits a zero plane at 200 yards.

Thanks alot everyone.  This has a lot of great information for those of us that have to travel a long way to an outdoor 100+ yard range.


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## awr72

i know if ya have big tall shoot thru mounts it could change but if ya have a low scope mount i dont know well see ill find out tmorrow


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## awr72

il disagree with ya on that one once the bullet leaves the barrel it has gravity against it just like everything else and wind drag and no more propellant no where to go but down.it dont gain speed loses it from the muzzle


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## awr72

ill put it to ya like this throw a football shotgun pass straight you can hit your target at short distance but a long hail mary you will throw it higher in a arc aiming up and using a rainbow trajectory to hit your target it never rises you compensate


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## awr72

that ball has gravity workin on it the time it leaves your hands the bullet never rises above the axixs of the barrel


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## bwsmith

awr72 said:


> il disagree with ya on that one once the bullet leaves the barrel it has gravity against it just like everything else and wind drag and no more propellant no where to go but down.it dont gain speed loses it from the muzzle



But remember you are not shooting perfectly flat without barrel rise unless your rifle is mounted to a tank


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## bwsmith

http://www.scdtechnologies.com/Hunter's Ballistics.htm


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## germag

bwsmith said:


> I am pretty sure they actually do rise out of the barrel.  A 308, as far as I know, hits a zero plane at 200 yards.
> 
> Thanks alot everyone.  This has a lot of great information for those of us that have to travel a long way to an outdoor 100+ yard range.



BW,
Bullets actually do not "rise". They are not an airfoil and do not produce any appreciable lift. When you fire a bullet, it subject to gravity from the microsecond it leaves the muzzle. It's a race against time...how far can it travel laterally before gravity pulls it to the ground. 

Consider this:

If you had a stretch of level ground that went as far as the eye can see...like the Bonneville Salt Flats, for instance....and you set up a rifle with the barrel perfectly level and parallel with the ground on a bench, say 36" high...and the fired a bullet from that rifle, BUT...at the exact same instant the bullet left the muzzle you also dropped a bullet from a position exactly even with the barrel of the rifle, both bullets would impact the ground at the same time....the same gravity is acting on each one. However, one of them will hit the ground WAAAAY out there, while the other one lands simultaneously on the ground beside the bench.

When you look through a scope, your line of sight is perfectly straight. The bore of the rifle is usually about 1.5" below the axis of the scope. If they are perfectly  parallel, the bullet will never intersect the line of sight through the scope...you would always be shooting low...never closer than the 1.5" distance between the scope and the bore. So, when you adjust the scope, what you are really doing in effect is tilting the barrel of the rifle upward in relation to the scope. That causes you to "loft" the bullet upwards. The bullet will actually then travel in an arc...crossing the line of sight twice...once on it's way up and again on it's way down.  Usually people will adjust the angle of intersection so that the first time the bullet crosses the line of sight will be at about 32 yards or so, then again at about 200 yards....it differs a little depending on a bunch of factors, such as velocity, bullet design, bullet weight, yadayada....but that puts most of them somewhere around 1.75-2.5" high at 100 yards.  What that really does is to give you a good "point blank range" so that for most commonly encountered hunting ranges you don't have to think about "holdover" and compensating for bullet drop....anywhere from right in front of you out to about 250-300 yards (once again depending upon the above mentioned factors) all you need to do is hold dead on and you will hit in the vital area of a deer.


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## awr72

i sight my 06 at 1 inch high at 100 yards


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## bwsmith

That makes sense Gerald.  I was always told that it was more a factor of muzzle rise.  This thread is chock full of usefull info.


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## bearpugh

to much for me to type, but bullet does not rise. the barrel is repositioned to compensate for sight or scope height.


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## bwsmith

bearpugh said:


> to much for me to type, but bullet does not rise. the barrel is repositioned to compensate for sight or scope height.



Don't worry, Gerald typed it all out


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## bearpugh

awr72 said:


> i sight my 06 at 1 inch high at 100 yards



me too. after you do that, shoot it at 25 and see where it hits. i know it sounds wrong. just like it doesn't sound right that heavier bullets hit higher than lighter ones.


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## Davans

germag said:


> BW,
> Bullets actually do not "rise". They are not an airfoil and do not produce any appreciable lift. When you fire a bullet, it subject to gravity from the microsecond it leaves the muzzle. It's a race against time...how far can it travel laterally before gravity pulls it to the ground.
> 
> Consider this:
> 
> If you had a stretch of level ground that went as far as the eye can see...like the Bonneville Salt Flats, for instance....and you set up a rifle with the barrel perfectly level and parallel with the ground on a bench, say 36" high...and the fired a bullet from that rifle, BUT...at the exact same instant the bullet left the muzzle you also dropped a bullet from a position exactly even with the barrel of the rifle, both bullets would impact the ground at the same time....the same gravity is acting on each one. However, one of them will hit the ground WAAAAY out there, while the other one lands simultaneously on the ground beside the bench.
> 
> When you look through a scope, your line of sight is perfectly straight. The bore of the rifle is usually about 1.5" below the axis of the scope. If they are perfectly  parallel, the bullet will never intersect the line of sight through the scope...you would always be shooting low...never closer than the 1.5" distance between the scope and the bore. So, when you adjust the scope, what you are really doing in effect is tilting the barrel of the rifle upward in relation to the scope. That causes you to "loft" the bullet upwards. The bullet will actually then travel in an arc...crossing the line of sight twice...once on it's way up and again on it's way down.  Usually people will adjust the angle of intersection so that the first time the bullet crosses the line of sight will be at about 32 yards or so, then again at about 200 yards....it differs a little depending on a bunch of factors, such as velocity, bullet design, bullet weight, yadayada....but that puts most of them somewhere around 1.75-2.5" high at 100 yards.  What that really does is to give you a good "point blank range" so that for most commonly encountered hunting ranges you don't have to think about "holdover" and compensating for bullet drop....anywhere from right in front of you out to about 250-300 yards (once again depending upon the above mentioned factors) all you need to do is hold dead on and you will hit in the vital area of a deer.



X2...you got it man....well said.


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## germag

bwsmith said:


> That makes sense Gerald.  I was always told that it was more a factor of muzzle rise.  This thread is chock full of usefull info.



Yeah, muzzle flip (a function of recoil) will change the point of impact somewhat. You can demonstrate that with a weighted shooting rest that you can strap the rifle down in, or by using a removable muzzle brake...but it's really not that much of a difference. My .300 Win Mag has about _maybe _a .5" difference in POI with the brake on as opposed to taking the brake off.


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## germag

bearpugh said:


> me too. after you do that, shoot it at 25 and see where it hits. i know it sounds wrong. just like it doesn't sound right that heavier bullets hit higher than lighter ones.



THAT is because of the increased recoil and resultant increase in muzzle flip.


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## awr72

im learnin some stuff here doesnt the paralex free if i spelled it right is different in a long out scope too i know 22 scopes has a lower rating ?


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## awr72

if ya dont mind guys explain that one to me i would like to know what that means i know i didnt spell it right


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## awr72

parallax free i know i spelled it wrong most long range scopes are not accurate that close and you are prob right with your 25 yard sight in


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## awr72

most of the high power are parallax free at 100 yards


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## awr72

a lot of small game guys go and buy a fancy 1inch deer rifle scope and mount it on there 22lr and wonder why they miss all the time


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## treemanjohn

Parallax is when a target and the reticle of a scope aren't in line ( difference in angles) . It causes  that goofy vapors/movement illusion in a scope. Adjustable objectives straighten out the problem.


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## ScottD

Parallax is when the target image and the reticle are not focused on the same plane.  Parallax is usually found to be a problem with higher power scopes, but all scopes have parallax.  Most hunting scopes are set to be "parallax free" at some midrange distance - the farther you use the scope from that distance - the more parallax you will have.

When you move your head around behind the scope - the crosshair will move on the target even though the rifle is stationary.  If the two images move in relation to one another - you have parallax.

The fuzzy vapor movement is mirage - it is caused by heat rising in front of the image - usually the mirage you see is just in front of the target.  Mirage does happen from heat off the barrel - but it just looks like the scope is out of focus - you really don't see the waves.

Yes a bullet does rise when it comes out of the barrel if the barrel in pointed up(not horizontal).  Think of it this way - if you shoot straight up the bullet definitely rises.  However if the bore is truly horizontal, then yes the bullet begins dropping immediately.

Rifle scopes are mounted above the bore, therefore the bore is always tilted up relative the the line of sight. Otherwise the bullet would never reach the line of sight. 







This image is exaggerated to show the bore tilted up when the scope is level.  The idea of sighting in at 25 yards is difficult to guess because the scope height off the bore comes into play, and like someone said, a small error at 25 yards becomes huge at longer distances.

Its also a good reason to mount the scope as low as possible to the bore.  That way the two lines are closer together and therefore the POI is closer to the Point of aim over a longer distance.

The other thing to remember is that a 40 grain bullet out of a 22LR drops just as fast as a 200grain bullet out of a 300 RUM.  The difference is that the bullet out of a 300 RUM travels much farther and faster as it drops.  Of course if you look at the numbers - so called "flat shooting" cartridges are not much of an improvement over standard cartridges unless you are not good as estimating range or shooting extreme distances.


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## Lowjack

Dead Eye Eddy said:


> .308 is comparable to .270.  I sight my .270 in 1" low at 25 yards.  I've killed deer from 20 yards to 250 yards with a dead on hold.  It's about 2.5" high at 100.  Don't sight it in high at 25, because you could miss a deer high at around 100-150 before the bullet starts dropping again.



What he said X2


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## awr72

but the bullet never goes higher than the plane of the barrel does it,i understand if you aim it up from horizontal it will gain altitude but i dont think the bullet will rise above the plane of the barrel?


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## Dead Eye Eddy

awr72 said:


> but the bullet never goes higher than the plane of the barrel does it,i understand if you aim it up from horizontal it will gain altitude but i dont think the bullet will rise above the plane of the barrel?



No, the bullet will never travel higher than the plane of the barrel.  The bullet only travels higher than the plane of sight because the barrel is angled upward while the scope is level.


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## DS7418

Dead Eye Eddy said:


> No, the bullet will never travel higher than the plane of the barrel.  The bullet only travels higher than the plane of sight because the barrel is angled upward while the scope is level.



Eddy got it correct..
 My Rem700 -- 30/06 is set 2" high at 100yrds.
When shot at 25yrds, the bullet will hit exactely 1-1/4" lower than the cross hair center.
 Ammo is a full power Nosler AccuBond-165gr.
scope is a Bushnell Elite 3x9x50mm ,,sitting very low near the barrel (lowest mounts possible).
 This scope is parrallex free at 100yrds.


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## AmericanBorn57

Wow what a conversation. Glad to see Germags points on rising. Are there a lot of women arguing points here? Point made - bullet starts off in the direction you intend on the plane of the barrel. It has no inherrent effect of lift - and just because a scope is 1" or 30" above the barrel, the bullet still has no lift, you are just pointing higher.  The missed point is on average, I really doubt an average (said average so if it doesn't apply to you, consider yourself above or below average on your own) the average shooter off-hand isn't going to be able to make a difference of 1/2 inch at 200 yards. That said, and thank you for the "cone" comment, small mistakes at the muzzle will be compounded downrange. Take care to make the best shot possible - with that .308 and soft points of some style, you'll be eating fresh venison out quite a ways. Dooly County does have some open fields so 250 yards isn't out of the question. Pop a cap on your lunch break to be sure!


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## awr72

thanks for your points to american born glad u straightened us all out,i know a lot of women who can outshoot me so what if they were discussing it with us?


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## awr72

would it be different from a ultra low scope mount to a high shoothru mount that is a 25 yard sight in?


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## germag

awr72 said:


> would it be different from a ultra low scope mount to a high shoothru mount that is a 25 yard sight in?



Yes. The distance between the center of the bore and the center of the scope will affect the zero at different distances. It changes the angle of the bore in relation to the line-of-sight through the scope.

For example:
(based on .308 Win 168 gr BTHP@2700 fps)

If you have a 1.5" scope height and you zero for 200y, you will be .1" low at 25y and 2.0" high at 100y

If you have a 2.5" scope height and you zero for 200y, you will be 1.0" low at 25y and 1.5" high at 100y


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## Hodaka

Decent calculator at Remington. com. You have to hunt for and register to download it. For free, you get to see any Rem. factory ammo, can adjust for scope heights, different sight in yardages, range yardages and calculate the "close-in" sight-in point for your gun.

After you have your gun sighted in, knowing the "close-in" sight-in is real helpful to do a quick check of your zero if you drop the gun, or just want a quick verify of your zero.


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## tjack

Wow, great discussion. With my M77 22" barrel shooting 180 grain federal soft points sighted dead on from a rest at 25yards I am 1 1/2" high at 100 yards, thats exactly where I like it.


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## WTM45

Everyone has to realize you must be VERY PRECISE at 25yds to be anything good at 100YDS or further regarding POI.

To have a 1" MOA rifle and shooter, that means the POI at 25yds must be in a .250 group RIGHT ON TOP OF THE POA!

It can not be "close" at 25yds.  It must be dead on.
Then confirm at 100yds (or further) to be sure.  Each rifle is different.

POI= Point of Impact
POA= Point of Aim


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