Re: Rifle Zero
[Re: Ranger109]
#6641991
10/17/19 01:54 PM
10/17/19 01:54 PM
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Joined: Feb 2015
Posts: 776 MN, USA
star flakes
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MN, USA
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You should always sight in any weapon on as level a plain as possible. Angles do matter as stated above and drastic is 10 degree plus. If you keep it under 5 degrees, as most people have a 3 degree difference, it will not make any "noticeable" difference, but raising and lowering a barrel is just like clicking on your rifle scope. So try to keep it on the level. As an example, I once shot at a mule buck, 100 yards, downhill, in the 35 to 40 degree range. I was zeroed 3 inches high, 30.06, 150 grain Winchester Silver Tips, and I hit about 3 inches over the top of the deer's back.
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Re: Rifle Zero
[Re: Ranger109]
#6641998
10/17/19 02:06 PM
10/17/19 02:06 PM
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Joined: Jul 2016
Posts: 1,482 Ne pa
Jerry Jr.
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Ne pa
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It will matter more that you know your true yardage and not just your line of sight distance. If you know your true yardage and sight in at a known distance and then go hunting and shoot at a animal that you know the true distance, if you do your part you will hit your mark.
Time is more precious than gold if you know how to spend it .... but what do I know, I'm just a dumb farmer.~My Dad NRA LIFE MEMBER, Endowment Member
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Re: Rifle Zero
[Re: bfflobo]
#6642077
10/17/19 03:56 PM
10/17/19 03:56 PM
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Joined: Dec 2006
Posts: 17,656 Rodney,Ohio
SNIPERBBB
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Rodney,Ohio
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All has to do with the pull of gravity. Has the most effect on everything going 100% horizontal. The more up or down the less effect of gravity. Faster the projectile the less time gravity has to effect it's pull. Star Flakes answer is best for a rifle. Need to sight in as flat as possible. Can really see the importance of gravity when shooting arrows at up or down angles compared to horizontal. To prove this phenomenon. Hold a fishing pole by the tip, hold it horizontal, assume this is your projectiles response to gravity. Then raise and lower it and watch how it straightens out the father it goes up and down. The same angle, up or down, is the same amount of deflection. Not true. Uphill downhill, if you dont aim low on both, you'll hit high or miss.
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Re: Rifle Zero
[Re: SNIPERBBB]
#6642082
10/17/19 04:02 PM
10/17/19 04:02 PM
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Joined: Aug 2019
Posts: 29 New York
Culvercreek
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New York
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All has to do with the pull of gravity. Has the most effect on everything going 100% horizontal. The more up or down the less effect of gravity. Faster the projectile the less time gravity has to effect it's pull. Star Flakes answer is best for a rifle. Need to sight in as flat as possible. Can really see the importance of gravity when shooting arrows at up or down angles compared to horizontal. To prove this phenomenon. Hold a fishing pole by the tip, hold it horizontal, assume this is your projectiles response to gravity. Then raise and lower it and watch how it straightens out the father it goes up and down. The same angle, up or down, is the same amount of deflection. Not true. Uphill downhill, if you dont aim low on both, you'll hit high or miss. That is what he is saying. less effect of gravity on the "drop" of the bullet. so it hits higher than the zeroed line of sight.
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Re: Rifle Zero
[Re: Ranger109]
#6642190
10/17/19 07:42 PM
10/17/19 07:42 PM
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Joined: Jul 2016
Posts: 1,482 Ne pa
Jerry Jr.
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You guys are talking about the distance in line of sight. Gravity can only effect the bullet over the distance that it travels over the earth. When shooting at angles the actual distance that gravity can affect the bullet is less than the line of sight (unless shooting at zero angle). Take a right angle triangle for example. The hypotenuse (the longest side) is your line of sight. The other leg is the actual distance to the target. On an extreme case, if your line of sight is 300 yards and you are shooting at a 45 degree angle (up or down does not matter) you would be shooting at a target that is only 212 yards away. Now, if you sighted your gun in at 300 yards line of sight at a 10 angle your true zero would be 295 yards.
By the way, don't forget to factor in the earths rotation. Don't forget mirage either.
Time is more precious than gold if you know how to spend it .... but what do I know, I'm just a dumb farmer.~My Dad NRA LIFE MEMBER, Endowment Member
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Re: Rifle Zero
[Re: Jerry Jr.]
#6642287
10/17/19 10:41 PM
10/17/19 10:41 PM
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Joined: Oct 2015
Posts: 3,077 Wyoming
cmcf
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Wyoming
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You guys are talking about the distance in line of sight. Gravity can only effect the bullet over the distance that it travels over the earth. When shooting at angles the actual distance that gravity can affect the bullet is less than the line of sight (unless shooting at zero angle). Take a right angle triangle for example. The hypotenuse (the longest side) is your line of sight. The other leg is the actual distance to the target. On an extreme case, if your line of sight is 300 yards and you are shooting at a 45 degree angle (up or down does not matter) you would be shooting at a target that is only 212 yards away. Now, if you sighted your gun in at 300 yards line of sight at a 10 angle your true zero would be 295 yards.
By the way, don't forget to factor in the earths rotation. Don't forget mirage either. Jerry Jr got it right. The distance to target via line of sight matters not. It is the horizontal distance that effects projectile drop. Uphill or down hill matters not. To answer the question the OP ASKED for zero at a given range the rifle and the target must be at the same elevation or “level “. As far as the coralis (sp) effect, spin of the earth is not a consideration except at long range = increased time of flight. Mirage can be a factor but I find that parallax will effect point of impact more if the scope is a fixed parallax model and the target is not at the fixed range. This is easy to observe, clamp the rifle in a fixed position with the x hairs on target and without touching the gun move your eye a little left to right or up and down if the parallax is not set for the distance to the target you will see the x hairs move off target.
“The world is governed by very different personages from what is imagined” B. Disraeli
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Re: Rifle Zero
[Re: jbyrd63]
#6642347
10/18/19 01:18 AM
10/18/19 01:18 AM
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Joined: Jan 2014
Posts: 7,694 Virginia
52Carl
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Down hill sniper I agree . Aim low . BUT up hill I found dead on or high . Opposite of down hill.......... If this is what you have experienced in the field shooting uphill, then I suspect that there is something else going on to cause you to go "dead on or high" to hit the target . For one thing, shooting position can be compromised when shooting at extreme uphill targets. This can pull your eye off center (up or down) at the ocular lens, causing parallax. This will throw ones shot off in a consistent manner, leading one to believe what you believe. Having said that, if you are able to get into the exact same position (out of position, actually) when shooting uphill, then your method will work for you.
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Re: Rifle Zero
[Re: jbyrd63]
#6642352
10/18/19 01:32 AM
10/18/19 01:32 AM
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Joined: Dec 2006
Posts: 17,379 Coeur d' Alene, Idaho
James
"Minka"
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"Minka"
Joined: Dec 2006
Posts: 17,379
Coeur d' Alene, Idaho
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Down hill sniper I agree . Aim low . BUT up hill I found dead on or high . Opposite of down hill.......... Wrong. You should aim low whether shooting uphill or downhill. It's the horizontal distance to the target's position that matters, not the line of sight. Jerry Jr., Cmcf, and 52Carl are right. And no, I won't bet you. Jim
Forum Infidel since 2001
"And that troll bs is something triggered snowflakes say when they dont like what someone posts." - Boco
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Re: Rifle Zero
[Re: Ranger109]
#6642391
10/18/19 06:09 AM
10/18/19 06:09 AM
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Joined: Jul 2012
Posts: 3,617 N. Carolina
Scout1
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N. Carolina
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Ok, so a stand I hunt I will shoot extreme downhill for up to four hundred yards. Farther east I shot a deer there was 330 yards. 300 win mag. I find the distance with my range finder, turn my scope dial to correct yardage, and then some of you guys are saying aim some low? Hey, not questioning anyone just trying to get the right answer here. Over the years depending on who you ask I would get both ways. In this particular cove I can shoot level, slightly uphill, to probably down to to around 25%. My favorite stand. For the longest time I believed shooting up or down hill was like throwing a rock. Uphill you better raise your sight. Down you aim under. I was told I was wrong, and probably am. Thanks in advance.
------------------------------------- DJT & MTG in 2024!
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Re: Rifle Zero
[Re: EdP]
#6642586
10/18/19 11:23 AM
10/18/19 11:23 AM
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Joined: Feb 2014
Posts: 13,155 Ky
jbyrd63
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Ky
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To say again what others have said, it is the horizontal distance that matters. The horizontal distance being the distance perpendicular to the direction of the force exerted by gravity. Consider the rather extreme case of a 45 degree angle up and a 45 degree angle down. The distance the bullet travels to the target is the same. The distance travelled perpendicular to the force of gravity is also the same but is shorter than the distance to the target. Given that it is the force of gravity that makes the bullet drop, the drop is the same whether or not the angle is up or down because the distance travelled perpendicular to the force of gravity is the same. So whether shooting up or down the bullet will drop less than if shooting on the horizontal. Ed you nailed it !! Key phrase DROP LESS !!! NOT no drop or Rises !!! If the shot is not very far then up hill or down it won't matter if you can hold the rifle still. It depends on what distance the rifle is zeroed......... There is an article on this that claims if it is 30 degree angle deduct 10% from yardage. on a 45 degree angle deduct 30% from yardage ...... So if my deer was at 100 yards (laser ranged) minus 10% I shoot him like he is at 90 yards !!! Yep still hold on his shoulder and call the gang !!!!!!!! https://ronspomeroutdoors.com/blog/uphill-downhill-shooting-dilemma-solved/
Last edited by jbyrd63; 10/18/19 11:24 AM.
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Re: Rifle Zero
[Re: Ranger109]
#6642643
10/18/19 01:02 PM
10/18/19 01:02 PM
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Joined: Feb 2010
Posts: 19,719 pa
hippie
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Your making this harder than it has to be Jbyrd. Up or down hill, your bullet drops less.
Here's one......... A bullet fired level from a gun will hit the ground at the same time as one dropped from your hand the same distance from the ground. Ground being level also of course.
In other words, they drop at the Same speed
Last edited by hippie; 10/18/19 01:03 PM.
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