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Posted: 6/19/2016 10:08:25 PM EDT
| I have a very nice custom built ar. 18 inch match barrel an larue trigger. Vortex crossfire II 4x16 50 scope. At 50 meters point of aim point of impact are the same. 6 round you can cover with a dime. 100 yard all rounds are about 9 inches low and a bit right. Using 55 grain vmax. Please help me understand why 50 yards makes such a negative change. |
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Quoted: I have a very nice custom built ar. 18 inch match barrel an larue trigger. Vortex crossfire II 4x16 50 scope. At 50 meters point of aim point of impact are the same. 6 round you can cover with a dime. 100 yard all rounds are about 9 inches low and a bit right. Using 55 grain vmax. Please help me understand why 50 yards makes such a negative change. Edit- are you grouping your rounds at 100? If so just adjust accordingly |
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So what's the issue the fact that your zeroed for 50 and want it to carry that over to 100?? The longer the range the more amplified mistakes. Hitting a dime group at 50 will not correlate to a group at 100. Edit- are you grouping your rounds at 100? If so just adjust accordingly Quoted:
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I have a very nice custom built ar. 18 inch match barrel an larue trigger. Vortex crossfire II 4x16 50 scope. At 50 meters point of aim point of impact are the same. 6 round you can cover with a dime. 100 yard all rounds are about 9 inches low and a bit right. Using 55 grain vmax. Please help me understand why 50 yards makes such a negative change. Edit- are you grouping your rounds at 100? If so just adjust accordingly This The shot is traveling in an arch so you are zeroed for 50yards it's going to peak high at 100 and will drop to around same point of impact at 200 as you had at 50. Think of yourself hold a garden hose with your thumb partially covering the hole. The stream is making an arch it's not a flat line. |
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Quoted: This The shot is traveling in an arch so you are zeroed for 50yards it's going to peak high at 100 and will drop to around same point of impact at 200 as you had at 50. Think of yourself hold a garden hose with your thumb partially covering the hole. The stream is making an arch it's not a flat line. Quoted: Quoted: Quoted: I have a very nice custom built ar. 18 inch match barrel an larue trigger. Vortex crossfire II 4x16 50 scope. At 50 meters point of aim point of impact are the same. 6 round you can cover with a dime. 100 yard all rounds are about 9 inches low and a bit right. Using 55 grain vmax. Please help me understand why 50 yards makes such a negative change. Edit- are you grouping your rounds at 100? If so just adjust accordingly This The shot is traveling in an arch so you are zeroed for 50yards it's going to peak high at 100 and will drop to around same point of impact at 200 as you had at 50. Think of yourself hold a garden hose with your thumb partially covering the hole. The stream is making an arch it's not a flat line. |
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No shots don't travel in an arc they straight until they start falling. But in a scope bullets seem to have a rise and fall characteristic but a bullet will never rise above the the point at which it was fired. Quoted:
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I have a very nice custom built ar. 18 inch match barrel an larue trigger. Vortex crossfire II 4x16 50 scope. At 50 meters point of aim point of impact are the same. 6 round you can cover with a dime. 100 yard all rounds are about 9 inches low and a bit right. Using 55 grain vmax. Please help me understand why 50 yards makes such a negative change. Edit- are you grouping your rounds at 100? If so just adjust accordingly This The shot is traveling in an arch so you are zeroed for 50yards it's going to peak high at 100 and will drop to around same point of impact at 200 as you had at 50. Think of yourself hold a garden hose with your thumb partially covering the hole. The stream is making an arch it's not a flat line. Wrong. You assume the bore and the line of sight are parallel, which they are NOT. |
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Quoted: Wrong. You assume the bore and the line of sight are parallel, which they are NOT. Quoted: Quoted: Quoted: Quoted: Quoted: I have a very nice custom built ar. 18 inch match barrel an larue trigger. Vortex crossfire II 4x16 50 scope. At 50 meters point of aim point of impact are the same. 6 round you can cover with a dime. 100 yard all rounds are about 9 inches low and a bit right. Using 55 grain vmax. Please help me understand why 50 yards makes such a negative change. Edit- are you grouping your rounds at 100? If so just adjust accordingly This The shot is traveling in an arch so you are zeroed for 50yards it's going to peak high at 100 and will drop to around same point of impact at 200 as you had at 50. Think of yourself hold a garden hose with your thumb partially covering the hole. The stream is making an arch it's not a flat line. Wrong. You assume the bore and the line of sight are parallel, which they are NOT. |
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Needless to say if you zero at 100yrds your bullet path will be straighter in trajectory.
http://aesirtraining.com/home/rifle-zero/ |
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That's why I said the when you look in a scope it will appear to rise, but it in fact does not. It leaves in a flat line out of the bore until drop occurs. Quoted:
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So what's the issue the fact that your zeroed for 50 and want it to carry that over to 100?? The longer the range the more amplified mistakes. Hitting a dime group at 50 will not correlate to a group at 100. Edit- are you grouping your rounds at 100? If so just adjust accordingly This The shot is traveling in an arch so you are zeroed for 50yards it's going to peak high at 100 and will drop to around same point of impact at 200 as you had at 50. Think of yourself hold a garden hose with your thumb partially covering the hole. The stream is making an arch it's not a flat line. Wrong. You assume the bore and the line of sight are parallel, which they are NOT. You're wrong, and right. A billet has no lift, however a barrel is almost never parallel to the ground so YES a bullet will go above the point where the barrel ends and the bullet exits from, but only because it is fired up and into the air, like a quarterback lofting a pass. The bullet has no lift so it doesn't go up on its own, but it can go higher. |
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That's why I said the when you look in a scope it will appear to rise, but it in fact does not. It leaves in a flat line out of the bore until drop occurs. You never took a first year Physics course did you? The whole concept of zero at 50 corresponding to zero at 200 is that the bore of the rifle is angled UPWARDS because at 50 the bullet has to travel UPWARDS to hit the point of aim of the sights. Because the sights are ~2" above the bore. The bullet NEVER TRAVELS IN A "STRAIGHT LINE". It ALWAYS TRAVELS IN A BALLISTIC TRAJECTORY. Gravity does not magically fail to affect the bullet between the muzzle and the 50 yard line. |
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Quoted: You never took a first year Physics course did you? The whole concept of zero at 50 corresponding to zero at 200 is that the bore of the rifle is angled UPWARDS because at 50 the bullet has to travel UPWARDS to hit the point of aim of the sights. Because the sights are ~2" above the bore. The bullet NEVER TRAVELS IN A "STRAIGHT LINE". It ALWAYS TRAVELS IN A BALLISTIC TRAJECTORY. Gravity does not magically fail to affect the bullet between the muzzle and the 50 yard line. Quoted: Quoted: That's why I said the when you look in a scope it will appear to rise, but it in fact does not. It leaves in a flat line out of the bore until drop occurs. You never took a first year Physics course did you? The whole concept of zero at 50 corresponding to zero at 200 is that the bore of the rifle is angled UPWARDS because at 50 the bullet has to travel UPWARDS to hit the point of aim of the sights. Because the sights are ~2" above the bore. The bullet NEVER TRAVELS IN A "STRAIGHT LINE". It ALWAYS TRAVELS IN A BALLISTIC TRAJECTORY. Gravity does not magically fail to affect the bullet between the muzzle and the 50 yard line.  |
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Guys..only a small portion to do with the OP's question as the disparity from 50 to 100 is way to large to be accounted for. A zero @ 50 should put you less than 1" high at 100. So let's back up a bit.
How was the gun held in place ? You ? Or locked down in a rest ? Could you have held the gun canted (Off Level) or are the cross hairs canted ? Did you double check the scope mount ? Did you try different ammo ? Double check breathing and trigger control ? How many rounds since cleaned ...? Go through the easy stuff first. |
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