Posted: 1/9/2009 10:49:31 PM EDT
| If I am zeroed for one hundred yars and the table says -10inches at 400 yards, Do I click up 40 times (1/4in per click scope) or is the 1/4 in per click only on at 100 yeards? |
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so if I clicked up 40 times and was 10 inches high at 100 yards I would be on at 400 yards? This seems to conflict with the above answers. Go slow I misspelled yards earlier. Impossible to say if it will be on at 400...it will be close Are you using the same grain weight as in the table? Same barrel length? it will be close but it's a trial and error. Once you find the right dope ...right it down in a log book and what round cartridge you used ETA 1/4 100 ...1 = 400 I hope we are making our selves clear 
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If I am zeroed for one hundred yars and the table says -10inches at 400 yards, Do I click up 40 times (1/4in per click scope) or is the 1/4 in per click only on at 100 yeards? 1/4 inch at 100, 1" at 400 yards. this is correct . your come up is 10 clicks @ 400 YARDS. ETA yes you have to actually shoot the distance and record it in your log book , the tables are never on the money. |
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If I am zeroed for one hundred yars and the table says -10inches at 400 yards, Do I click up 40 times (1/4in per click scope) or is the 1/4 in per click only on at 100 yeards? 1/4 inch at 100, 1" at 400 yards. this is correct . your come up is 10 clicks @ 400 YARDS. ETA yes you have to actually shoot the distance and record it in your log book , the tables are never on the money. So now I am 2.5 inches high at 100 yards and dead on at 400 yards. If the bullet drops ten inches in 300 yards we just defied physics didn't we???? |
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cweb...
Maybe this is not your question, but it's one thing if you are zeroing to shoot paper at a specific distance, and another if you are shooting game that might be moving. If you are zeroing to shoot game, you may be better served by zeroing at a specific "point blank" distance. (IE: 200 yards as opposed to 400 yards) You still need to understand the ballistics, but the point blank zero is far more useful for aiming in the field. |
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cweb... Maybe this is not your question, but it's one thing if you are zeroing to shoot paper at a specific distance, and another if you are shooting game that might be moving. If you are zeroing to shoot game, you may be better served by zeroing at a specific "point blank" distance. (IE: 200 yards as opposed to 400 yards) You still need to understand the ballistics, but the point blank zero is far more useful for aiming in the field. I am not planning on shooting anything but it is something I have always wondered about. You look at the shooters bible and it lists ballistics as 100yrds 0 200yrds -2 300yrds-6 400yrds -10 If I was 10 inches high at 100 would I be on at 400? If the scopes clicks are .25 inches and that equals 1 inch at 400yrds, ten clicks would put me 2.5 inches high at 100 and on at 400. which doesn't sound right AT ALL. |
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If the scopes clicks are .25 inches and that equals 1 inch at 400yrds, ten clicks would put me 2.5 inches high at 100 and on at 400. which doesn't sound right AT ALL.
Yes it does. 10x .25=2.5 @ 100 10x1=10 @ 400. So the bullet would impact 2.5 inches high at 100 and dead on at 400, a drop of 2.5 inches If I was on at 100 and 10inches low at 400 it is going to drop 10 inches. Which one is right? |
| You are thinking of the muzzle being level with the target and the only effect on bullet flight being gravity. By moving your impact 2.5 high you have changed the launching angle of your muzzle. This is why trajectory charts are shown as a rainbow and not just a flat descending line. |
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You are thinking of the muzzle being level with the target and the only effect on bullet flight being gravity. By moving your impact 2.5 high you have changed the launching angle of your muzzle. This is why trajectory charts are shown as a rainbow and not just a flat descending line. I know that, I was just testing you guys. 
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If the scopes clicks are .25 inches and that equals 1 inch at 400yrds, ten clicks would put me 2.5 inches high at 100 and on at 400. which doesn't sound right AT ALL.
Yes it does. 10x .25=2.5 @ 100 10x1=10 @ 400. So the bullet would impact 2.5 inches high at 100 and dead on at 400, a drop of 2.5 inches If I was on at 100 and 10inches low at 400 it is going to drop 10 inches. Which one is right? Because by being 2.5in high at 100, you are now shooting your bullet at an even more upwards trajectory than the upwards trajectory which had you spot on at 100 but 10in low at 400. |
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If the scopes clicks are .25 inches and that equals 1 inch at 400yrds, ten clicks would put me 2.5 inches high at 100 and on at 400. which doesn't sound right AT ALL.
Yes it does. 10x .25=2.5 @ 100 10x1=10 @ 400. So the bullet would impact 2.5 inches high at 100 and dead on at 400, a drop of 2.5 inches If I was on at 100 and 10inches low at 400 it is going to drop 10 inches. Which one is right? It's not dropping 2.5 inches, it's dropping 2.5 moa. It has a path. At 100 yards, the bullet is still going up in order to come down to the target. Think of a piece of pie, cut into 8 equal pieces. How wide is the crust on 10" pie? How about a 20" pie? It gets bigger. 1 moa is 1 moa. 1 click is 1/4 moa. 1/4 moa at 100 yards is 1/4". 1/4 moa at 400 yards is 1". 1/4 moa at 1200 yards is 3". ETA: So in your original post, if you went up 40 clicks, you would be raising your point of impact by 40 inches. Rather than being 10" low, you would be 30" high. |
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If I am zeroed for one hundred yars and the table says -10inches at 400 yards, Do I click up 40 times (1/4in per click scope) or is the 1/4 in per click only on at 100 yeards? 1/4 inch at 100, 1" at 400 yards. this is correct . your come up is 10 clicks @ 400 YARDS. ETA yes you have to actually shoot the distance and record it in your log book , the tables are never on the money. So now I am 2.5 inches high at 100 yards and dead on at 400 yards. If the bullet drops ten inches in 300 yards we just defied physics didn't we???? Do you really not understand how this works? I assure you that physics was not defied. If your zero at 100yds becomes -10.0 at 400yds, the apex of your trajectory was somewhere before 100yds. When you adjust your sights to be +2.5" at 100yds, the apex of your trajectory is probably somewhere beyond 100 yards. The bullet travels in an arc. Change the angle of departure and you change the entire flight path. |
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First, realize you have TWO "Zeros", near and far. The two zeros are "Point Blank Range" with a point size of zero. The sights stay level relative to the ground, when you adjust the sights, you are tilting the barrel up or down, so that the bullet will climb to meet the line of sight at the desired range. For a 100yd, "close zero" is usually under/at 40yds. With a "generic hunting round of average muzzle velocity" (no, it doesn't exist), "Zeroing" a hunting rifle for 1" high at 100yds pretty much puts the bullet impact (POI) within 2.5" of Point Of Aim (POA) from Zero to about 220yds. This means the "Point Blank Range" is now an oval about 5" tall where the bullet will most likely impact, between a maximum of +2.5" and -2.5", and left/right depending on wind and bullet weight. For 2.5" high @100 to be a zero at 400, you must have a high velocity rifle using bullets with a Great Ballistics Coefficient (BC). Here is a Ballistics chart for a 400yd Zero using a decent Barnes Bullet. Notice that impact is nearly 7" high at 100yds. Point Blank Range/24" is 475yds, i.e. bullet will hit within a foot of point of aim from zero to 425, highest being 11 inches @ 224, lowest being -12" @ about 475yds
Same bullet/velocity, Zero at 175 (1.1" high at 100), POI within 2" of POA out to 220 (Assuming Scope is mounted 1.5" above bore)
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You are thinking of the muzzle being level with the target and the only effect on bullet flight being gravity. By moving your impact 2.5 high you have changed the launching angle of your muzzle. This is why trajectory charts are shown as a rainbow and not just a flat descending line. I know that, I was just testing you guys.  
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