# Scope Accuracy at Close Range



## GIDEON (Mar 28, 2008)

ESOX said:


> The bullet may rise above the direct line of sight from the scope to the target.
> But the bullet will never rise above an imaginary line drawn from center line of the bore of the rifle.


 OK, if you say so.


----------



## radiohead (Apr 11, 2006)

That's interesting.
So if that's a 150 yard target (for sake of discussion), you would actually be low up close, then at a point of say 75 yards you would actually be high.



tgafish said:


> Here ya go buddy. At 15 to 20 yards the blue line is still below the black line. Hope this helps


----------



## tgafish (Jan 19, 2001)

Probably be highest at 100 yards. The actual curves are not as uniform as you see here. The curve drops exponetially the farther you go. That fast drop comes closer and closer as your bullet weight goes up and intial velocity goes down in firearms such as shotguns and ML's vs rifles.


----------



## wintrrun (Jun 11, 2008)

radiohead said:


> That's interesting.
> So if that's a 150 yard target (for sake of discussion), you would actually be low up close, then at a point of say 75 yards you would actually be high.


exactly.
And bullet weight and most importantly velocity of that round determine what kind of ARC (trajectory) you will have.


----------



## jjc155 (Oct 16, 2005)

The reason that the point of impact is lower than point of aim at close distance is very simply because the scope and thus your eye are looking at a differnent spot, which is in line with a line above the barrel, if that makes sense.

If you were able to have a scope that actually looked down the center of the bore the POI and the POA would be the same. It is simply that the center line of the bore is below the center line of your sight and the trajectory has not crossed the line of sight yet.

On a side note you could stand to use lower rings on your gun, if you can get the scope to fit. When mounting a scope on a rifle I strive to get the bottom of the front "bell" as close to the barrel as possible. 

This does two things (at least for me) 1) it lessens the difference in POI and POA at close distance, which is not a huge deal on a deer but is the matter between a hit and a miss on a squirrel or other small game.
2) it allows me to get a better cheek weld on the stock and thus make repeatable mounting and firing of the gun easier. With too high of a mount, you have to have your cheek off the stock with is kind of like having a floating anchor in archery.

Hope this helps,
J-


----------



## radiohead (Apr 11, 2006)

It's ironic you mention that because the reason I went with mounting rings to elevate the scope was so I could use the iron sights on the barrel if I had something at close range 

I just have not practiced enough with the iron sights to comfortably shoot at an animal with confidence. I think this offseason I am going to get the scope remounted on the barrel since I know how to adjust my shot through the scope at close range.



jjc155 said:


> On a side note you could stand to use lower rings on your gun, if you can get the scope to fit. When mounting a scope on a rifle I strive to get the bottom of the front "bell" as close to the barrel as possible.
> 
> This does two things (at least for me) 1) it lessens the difference in POI and POA at close distance, which is not a huge deal on a deer but is the matter between a hit and a miss on a squirrel or other small game.
> 2) it allows me to get a better cheek weld on the stock and thus make repeatable mounting and firing of the gun easier. With too high of a mount, you have to have your cheek off the stock with is kind of like having a floating anchor in archery.
> ...


----------



## Swamp Monster (Jan 11, 2002)

GIDEON said:


> You sure of this?


Yes. I'll say it again, bullets don't rise and no your pomposness won't make it so.
_Posted via Mobile Device_


----------



## UNREEL (Jun 8, 2007)

jjc155 said:


> The reason that the point of impact is lower than point of aim at close distance is very simply because the scope and thus your eye are looking at a differnent spot, which is in line with a line above the barrel, if that makes sense.
> 
> If you were able to have a scope that actually looked down the center of the bore the POI and the POA would be the same. It is simply that the center line of the bore is below the center line of your sight and the trajectory has not crossed the line of sight yet.
> 
> ...


This. If time allows, get some different rings. A 2" centerline above bbl is way high IMO, but only if you can remove iron sights. Quality is key on rings, Leupold or Burris. My Omega wears a 40mm Nikon with Leupold rings, bell about 1/32" off bbl. My 1100 wears a 50mm Leupold, can barely slide a dollar bill under the bell.
_Posted via Mobile Device_


----------



## UNREEL (Jun 8, 2007)

You type faster than I do, I see you already got it!!
_Posted via Mobile Device_


----------



## Swamp Monster (Jan 11, 2002)

GIDEON said:


> Your assumption is correct


No it isn't. Radiohead, do not listen to Gideon...his info can be considered "white noise" so disregard.
_Posted via Mobile Device_


----------



## wally-eye (Oct 27, 2004)

Sort of.....

http://www.chuckhawks.com/bullet_trajectory.htm


----------



## Swamp Monster (Jan 11, 2002)

wally-eye said:


> Sort of.....
> 
> http://www.chuckhawks.com/bullet_trajectory.htm


Not really. Read the article and you see that it might rise but that will be because the muzzle is pointed upward slightly. Hold the bore parallal to ground and pull the trigger and the bullet will not rise, it will start dropping immediately....how much depends on velocity, B.C. Wind resistance etc.
_Posted via Mobile Device_


----------



## radiohead (Apr 11, 2006)

So your scope is set up to cause you to slighty point your barrel up from parallel, this causes the bullet's trajectory to rise slightly when it leaves your barrel?


----------



## UNREEL (Jun 8, 2007)

radiohead said:


> So your scope is set up to cause you to slighty point your barrel up from parallel, this causes the bullet's trajectory to rise slightly when it leaves your barrel?


Yes
_Posted via Mobile Device_


----------



## radiohead (Apr 11, 2006)

Wow...3 pages later and I got it. Not bad for an Anchor Bay graduate :lol:




UNREEL said:


> Yes
> _Posted via Mobile Device_


----------



## UNREEL (Jun 8, 2007)

Knew you'd get it.
_Posted via Mobile Device_


----------



## jjc155 (Oct 16, 2005)

UNREEL said:


> This. If time allows, get some different rings. A 2" centerline above bbl is way high IMO, but only if you can remove iron sights. Quality is key on rings, Leupold or Burris. My Omega wears a 40mm Nikon with Leupold rings, bell about 1/32" off bbl. My 1100 wears a 50mm Leupold, can barely slide a dollar bill under the bell.
> _Posted via Mobile Device_


Yep Burris Signature Z rings are on all my scoped rifles. I try to set the height so that a dollar bill just slides between the bottom of the front bell and the barrel. that is all you need for clearance.

J-


----------



## NoWake (Feb 7, 2006)

tgafish said:


> Here ya go buddy. At 15 to 20 yards the blue line is still below the black line. Hope this helps


A picture is worth a thousand words.


----------



## GIDEON (Mar 28, 2008)

Swamp Monster said:


> Yes. I'll say it again, bullets don't rise and no your pomposness won't make it so.
> _Posted via Mobile Device_



It is not pomposness, Evidently you and I have read different articles and studies. that's all.


----------



## Sam22 (Jan 22, 2003)

tgafish said:


> Here ya go buddy. At 15 to 20 yards the blue line is still below the black line. Hope this helps


Good Diagram thank you! this stuff is not all cut and dry. And Gideon, no bullets don't rise above the imaginary line coming straight out of and down the bore. That wouldn't make sense unless the bullet were shaped like a frisbee or something. 



UNREEL said:


> This. If time allows, get some different rings. A 2" centerline above bbl is way high IMO, but only if you can remove iron sights. Quality is key on rings, Leupold or Burris. My Omega wears a 40mm Nikon with Leupold rings, bell about 1/32" off bbl. My 1100 wears a 50mm Leupold, can barely slide a dollar bill under the bell.
> _Posted via Mobile Device_


Really that close? I have been told that if they are so close they nearly tough (ie the dollar bill) that when the barrel heats up it will touch the scope even push it, and the gun accuracy will suffer.


----------



## NoWake (Feb 7, 2006)

Sam22 said:


> Really that close? I have been told that if they are so close they nearly tough (ie the dollar bill) that when the barrel heats up it will touch the scope even push it, and the gun accuracy will suffer.


A dollar bill is about .004 in. Steel expands about .0000065 inches per degree per inch. 

So hypothetically, if your barrel was solid and 1 inch in diameter, it would grow .00065 inches for every 100 degrees hotter. Unless I screwed up somewhere I think it would take about a 600 degrees increase before the barrel would make contact.


----------



## GIDEON (Mar 28, 2008)

NoWake said:


> A dollar bill is about .004 in. Steel expands about .0000065 inches per degree per inch.
> 
> So hypothetically, if your barrel was solid and 1 inch in diameter, it would grow .00065 inches for every 100 degrees hotter. Unless I screwed up somewhere I think it would take about a 600 degrees increase before the barrel would make contact.


 Just for the sake of conversation: By design your barrel cant be solid. So when you take a solid 1" solid piece, and then subtract the bore of your rifle, then take into account the type of steel used in your barrel, how much do you think that this would affect your formula. This is a topic that has been discussed, debated by Gunsmiths, and manufacturers for years.


----------



## Swamp Monster (Jan 11, 2002)

GIDEON said:


> It is not pomposness, Evidently you and I have read different articles and studies. that's all.


:lol::lol: The pompos thing was more of a compliment btw.....


----------



## GIDEON (Mar 28, 2008)

Swamp Monster said:


> :lol::lol: The pompos thing was more of a compliment btw.....



No problem either way


----------



## NoWake (Feb 7, 2006)

GIDEON said:


> Just for the sake of conversation: By design your barrel cant be solid. So when you take a solid 1" solid piece, and then subtract the bore of your rifle, then take into account the type of steel used in your barrel, how much do you think that this would affect your formula. This is a topic that has been discussed, debated by Gunsmiths, and manufacturers for years.


To be honest, I am not 100% sure what difference subtracting the bore would be, but in my opinion it would probably decrease the expansion rate but increase the speed that the barrel heats up. By using a solid piece, it was my intention to give a worst case scenerio, but maybe that's not the case. Are you saying a 1 inch OD tube with a .350 inch wall thickness expands at a higher rate than a 1 inch solid rod? Maybe it does, I don't know for sure.

IMO the type of steel wouldn't make enough of a difference in this case.


----------



## sweatyspartan (May 24, 2004)

GIDEON said:


> It is not pomposness, Evidently you and I have read different articles and studies. that's all.


You must be more versed in the studies that came out before Issac Newton was born


----------



## GIDEON (Mar 28, 2008)

sweatyspartan said:


> You must be more versed in the studies that came out before Issac Newton was born


 Actually the study was done by engineers at Vanderbuilt University, and Engineers employed by B.B.N. industries, late 1990s to mid/early 2000s (I think SCHMIDT&BERGER were there names), The results of the test were incorporated into the BOOMERANG project. So it was well after Issac Newtons time.


----------



## GIDEON (Mar 28, 2008)

radiohead said:


> My muzzleloader w/ scope is dialed in for 100 yards. My question is, let's say if have a deer at close range, say 15-20 yards. Is the scope going to be accurate at such a close range when I have it sighted in out 100 yards?


 Radio head: the information I was referring to, reguarding bullit drop and rise was originally written by a man named Rawling's, (If my memory is working), from CSOT. I actually lost interest in the thread and never looked up his article. However this week I ran across an article that does a good job of explaining it, complete with diagrams. I am not much on being able to cut and paste,so if your still interested: July 22 2011, issue of Michigan Outdoor News, page 16.


----------



## radiohead (Apr 11, 2006)

Thanks Gideon.
I'll try to get my hands on that article.



GIDEON said:


> Radio head: the information I was referring to, reguarding bullit drop and rise was originally written by a man named Rawling's, (If my memory is working), from CSOT. I actually lost interest in the thread and never looked up his article. However this week I ran across an article that does a good job of explaining it, complete with diagrams. I am not much on being able to cut and paste,so if your still interested: July 22 2011, issue of Michigan Outdoor News, page 16.


----------

