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April 25, 2017, 02:49 PM | #26 |
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The difference in bullet drop between 100 and 200 yards depends completely on the velocity of the bullet. As someone already pointed out, the acceleration of gravity (here on earth) is a constant. Only the time that gravity is pulling on the bullet determines its drop. Slower bullets take longer to get to their targets and have a greater velocity in the downward direction than faster bullets.
A 38 special bullet drops further from 100 yards to 200 yards than a 30-06 bullet because the 38 bullet takes longer to get there. The two bullets have the same drop over the same time periods but the faster bullet goes farther in that time. |
April 25, 2017, 03:14 PM | #27 |
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I want to thank you all for your replies, I know the guy meant well, I just have a hard time with such overall generalizations. To hit a 7" tall steel gopher at 200 yds with a 223 zeroed at 100, how tough is that?
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April 25, 2017, 05:36 PM | #28 | |
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Just curious, how old is this person? As generalizations go, "most centerfire rifles have about 3" of drop between 100 and 200 yards" is not a bad one. Looking at the chart on the link you provided, damn near all of the more common calibers fall between 2.5 and 3.5 inches of drop between 100 and 200 yards. It is less true once you get above .30 caliber, because the bullets get heavier and tend to be slower. Sure, there are exceptions, 220 Swift, and some of the magnums have less, .30-30 and a few others have more. So for most rifles he is right, coming up 3", or 1.5 MOA from your 100 yard zero will put you within 1/2 MOA for elevation at 200. On the target you describe, taller than it is wide, that will be fine. The "Just zero it at 50 it will be on at 200" I am much more skeptical of. |
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April 25, 2017, 06:40 PM | #29 |
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Just because we're old, it doesn't mean we're stupid. I'm 69 and know the trajectory of my various calibers (9 rifle) I handload for and how they'll preform in a given rifle. While sighting in at 100 yds was the given when I started shooting 60 yrs ago, I realized 15 yrs ago that when I sight in my rifle at 200 yds, I've got a much more useful operating range where my bullet path is within ± 2" of the sightline.
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April 25, 2017, 06:48 PM | #30 |
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COSteve, Well put and my point exactly, I load for 4 different calibers in 7 rifles and I know how each one performs, whether I zero for 100 or 200 yds. And yes steve, we are old but not stupid...
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April 25, 2017, 06:52 PM | #31 |
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TJB101 - Time to get a new ballistic calculator. Zeroed at 100 yds with a sight height above the bore centerline of .9" (typical irons height of a bolt gun), you're 2.88" low at 200 yds using your velocities and a 55grn spitzer pointed boat tail bullet. With a sight height of 2.6" (height of an AR sights) and again, sighted in at 100 yds, you're 1.88" low at 200 yds.
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April 25, 2017, 09:33 PM | #32 |
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"Drop" as stated in the ballistics tables is measured from the line of the bore. "Path" as stated earlier is a curve measured from the line of sight. Look at the drop column in the ballistics tables and you will see that all bullets drop like crazy after 300 yards, regardless of the cartridge, due to the acceleration of gravity.
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April 25, 2017, 09:34 PM | #33 | |
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He is wrong though when he says "Tad over 1/2 in drop @ 200 yards". That column is not in inches, it is in MOA, so instead of .6" low it is .6 MOA low, or 1.2 inches at 200 yards. Not perfect, but if you did that you should be able to hit a 7" tall target at 200 yards. |
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April 26, 2017, 10:04 AM | #34 |
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For most "deer cartridges" and the vast majority of all shots at Bambi, if you zero for 2" high at 100 yards, you can quit thinking.
"Just point it and pull. The freezer ain't half-full." |
April 26, 2017, 02:09 PM | #35 |
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Amen Art. I have been preaching for years that if you just sight in about 2 1/2 inches high at 100 yards, you will maximize the point blank range for deer with just about any rifle. I won't quibble about a half inch.
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April 26, 2017, 03:07 PM | #36 |
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I am right there with both of you art and math, my thoughts exactly, no need to think..
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April 26, 2017, 03:16 PM | #37 | ||
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Either way, if the OP copied the printout of a ballistic calculator that gave those readings, then that calculator is dead wrong . . . inches or MOA, it don't matter cause the bullet starts dropping and slowing down the instant it leaves the barrel, not 50 yds down range. |
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April 26, 2017, 03:55 PM | #38 |
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Bullet drop from 100 to 200 yds
Ballistics tell all. Drop is determined by the grain of the bullet and the powder grain, along with the length of the barrel with the round.
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April 26, 2017, 06:27 PM | #39 | |
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Flight time is determined by velocity, both initial (muzzle) velocity, and retained velocity at the target (which varies by ballistic coefficient). Again, while not perfect, if someone showed up at the range and wanted to make hits at 200 yards, with unknown muzzle velocity and BC, and you didn't have access to a ballistic calculator, assuming ~3", or 1.5 MOA, of drop to 200 yards is a pretty good rule of thumb. |
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April 27, 2017, 02:49 PM | #40 |
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If you don't know muzzle velocity or ballistic coefficient a ballistics calculator would be worthless any way. If you are at the range and want to hit at 200 yards then sight it in at 200 yards. With my 30-06 I hit just under 1" high at 100 yards and right at 1 inch low at 200 yards. My point blank range is calculated on no more than 1 inch above or below point of aim.
The '06 is dead on at 174 yards. |
April 27, 2017, 03:41 PM | #41 | ||
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April 27, 2017, 08:31 PM | #42 |
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Bullet drop depends on several thing's and not one thing. Of course the most obviously velocity does effect it. Actually velocity effect's time of flight. Equal bullet's started at different velocity will show different drop because of time of flight. Barrel length will effect drop for no other reason than equal loads fire in two different rifles with different barrel lengths will give less drop to the longer barrel for no other reason than time of flight is longer for the longer barrel. Bullet shape will also effect drop. A round nose bullet is ballistically inferior to an equal weight spitzer type bullet. Even if started at the same velocity, the spitzer will cut the air a lot better and maintain a velocity advantage once they are fired, time of flight is effected. The way you sight in your rifle will also effect bullet drop. ie: sight in the rifle at 100 yds dead on and then take the same rifle and load and re-sight at some farther distance. The time of flight doesn't really change other than the trajectory you've given the same bullet. Your 30-06 with a 180gr bullet sighted in dead on at 100 yds will hit the ground sooner than the same exact load from the same rifle but sighted in at a longer distance. For every rifle there is a sweet spot and that is determined by the size of the trget your shooting at. If you sight in to hit a 4" target and never have the bullet go more than 2" high or 2" low all the way to the target, time of flight will be effected for no other reason than the trajectory you chose. Take the same load and the same rifle and sight it in for an 8" target and the same rifle/load will hit the bigger target farther away. The bullet with the 8" target takes the bullet farther without ever leaving the 8" circle by 4" high and 4" low, that is 4" above and below the line of sight. Changing the sight in to take advantage of what you want from your rifle and what it has to give you will, because of trajectory, change time of flight.
Take a 180gr bullet and drop it in front of the barrel and it will hit the ground at the same time s the same bullet actually fired from the rifle perfectly level to the ground. The distance each falls will be exactly the same but without trajectory made with sight alignment, nothing changes. When a bullet leave's the barrel, any bullet, it immediately start's to fall. It rise's above line of sight because of the trajectory you give it by sighting it in at some particular range. |
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