There are not two kinds of minutes of angle. A circle is divide into 360 degrees and each degree is divided into 60 minutes so one minute of angle is 1/60 of one degree and this equates to 1.0472" of angle at 100 yards.In other words if you drew a straight line and a secound line that angeled away from the straight line by one minute of angle then at 100 yards they would be 1.0472" apart not 1" if you are useing minutes of angle there is only one.
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Bullet drop compensation dials (BDC dials)
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Jon A
Well-Known Member
I agree. If a scope says MOA it should be assumed 1.047" @ 100 until measured otherwise. That's not to say there aren't 1" @ 100 scopes (by design or not). I think US Optics will build you one in SMOA, but it'll be labeled SMOA. Checking "the company line" for a few manufacturers, for USO MOA is MOA, Leupold when listing both MOA and inches uses actual MOA and from what I can tell from Nightforce they do as well (they say a 2 MOA reticle is "approximately 2" at 100 yds).
Every ballistic program I've used (that doesn't have an input to adjust it) uses MOA = 1.047" @ 100.
All that said, measuring is the only way to be sure (your particular scope might not be either exactly).
Every ballistic program I've used (that doesn't have an input to adjust it) uses MOA = 1.047" @ 100.
All that said, measuring is the only way to be sure (your particular scope might not be either exactly).
goodgrouper
Well-Known Member
I knew they were going to give you the run around.
I asked the very same q's to Art Pejsa (self proclaimed ballistics guru), Sierra techs, Berger, Exbal/perry, and several others about a year ago and got the old "we make the programs the way we make them" routine. <font color="red">None of these guys will even admit that their precious programs all make you shoot a couple clicks low at 700+ yards and as much as a minute and a half low at 1k depending on bc and velo. </font>
Same thing goes for when I asked them about their stupid uphill downhill zero features that don't move your second bullet/line of sight crossing further out with an angle shot!
C'mon program writers. This is simple and could easily be remedied.
BTW, we should probably take this topic to another subsection and start another thread so people won't loose out on this valuable info. Otherwise, they might attempt to shoot a deer or something at 1k and use their straight info from Exbal and shoot the legs off an animal.
I asked the very same q's to Art Pejsa (self proclaimed ballistics guru), Sierra techs, Berger, Exbal/perry, and several others about a year ago and got the old "we make the programs the way we make them" routine. <font color="red">None of these guys will even admit that their precious programs all make you shoot a couple clicks low at 700+ yards and as much as a minute and a half low at 1k depending on bc and velo. </font>
Same thing goes for when I asked them about their stupid uphill downhill zero features that don't move your second bullet/line of sight crossing further out with an angle shot!
C'mon program writers. This is simple and could easily be remedied.
BTW, we should probably take this topic to another subsection and start another thread so people won't loose out on this valuable info. Otherwise, they might attempt to shoot a deer or something at 1k and use their straight info from Exbal and shoot the legs off an animal.
goodgrouper
Well-Known Member
[ QUOTE ]
There are not two kinds of minutes of angle. A circle is divide into 360 degrees and each degree is divided into 60 minutes so one minute of angle is 1/60 of one degree and this equates to 1.0472" of angle at 100 yards.In other words if you drew a straight line and a secound line that angeled away from the straight line by one minute of angle then at 100 yards they would be 1.0472" apart not 1" if you are useing minutes of angle there is only one.
[/ QUOTE ]
That is correct. But what we are trying to say is that the ballistic programs aren't giving you info that directly transcribes to what your scope actually does.
YOur scope moves the reticle 1" at 100 yards and not 1.0472" which is what the program is telling you to move the turret. So when you get out there aways, that .0472 starts to add up and becomes prevalent. Rather than have everyone send in their scopes to be retro-fitted to move the actual 1.0472, it is easier to have the hackers write a program that actually <font color="red"> calculates in the same language your scope talks! </font>
Does this help clarify?
There are not two kinds of minutes of angle. A circle is divide into 360 degrees and each degree is divided into 60 minutes so one minute of angle is 1/60 of one degree and this equates to 1.0472" of angle at 100 yards.In other words if you drew a straight line and a secound line that angeled away from the straight line by one minute of angle then at 100 yards they would be 1.0472" apart not 1" if you are useing minutes of angle there is only one.
[/ QUOTE ]
That is correct. But what we are trying to say is that the ballistic programs aren't giving you info that directly transcribes to what your scope actually does.
YOur scope moves the reticle 1" at 100 yards and not 1.0472" which is what the program is telling you to move the turret. So when you get out there aways, that .0472 starts to add up and becomes prevalent. Rather than have everyone send in their scopes to be retro-fitted to move the actual 1.0472, it is easier to have the hackers write a program that actually <font color="red"> calculates in the same language your scope talks! </font>
Does this help clarify?
goodgrouper
Well-Known Member
[ QUOTE ]
I agree. If a scope says MOA it should be assumed 1.047" @ 100 until measured otherwise.
[/ QUOTE ]
If you assume that you will be guaranteed to have nothing but frustration trying to make things work out.
I agree. If a scope says MOA it should be assumed 1.047" @ 100 until measured otherwise.
[/ QUOTE ]
If you assume that you will be guaranteed to have nothing but frustration trying to make things work out.
Jon A
Well-Known Member
That's why I say measure. I know I'm not going to guarantee everybody's scope is exactly 1.00". Are you?
[ QUOTE ]
[ QUOTE ]
There are not two kinds of minutes of angle. A circle is divide into 360 degrees and each degree is divided into 60 minutes so one minute of angle is 1/60 of one degree and this equates to 1.0472" of angle at 100 yards.In other words if you drew a straight line and a secound line that angeled away from the straight line by one minute of angle then at 100 yards they would be 1.0472" apart not 1" if you are useing minutes of angle there is only one.
[/ QUOTE ]
That is correct. But what we are trying to say is that the ballistic programs aren't giving you info that directly transcribes to what your scope actually does.
YOur scope moves the reticle 1" at 100 yards and not 1.0472" which is what the program is telling you to move the turret. So when you get out there aways, that .0472 starts to add up and becomes prevalent. Rather than have everyone send in their scopes to be retro-fitted to move the actual 1.0472, it is easier to have the hackers write a program that actually <font color="red"> calculates in the same language your scope talks! </font>
Does this help clarify?
[/ QUOTE ]
I agree. I just wanted to clear up the cofussion about the two,apparently I was not clear enough.I did not intend to infer that all scopes adjusted in moa.Some scopes are advertised to have adjustments of 1/8" or1/4" adjustments and others claim to adjust in 1/8 or 1/4 moa at 100 yards.
I also agree that actual shooting at distance is the only way to know for sure.This discrepancy is why many find that thier drops are off when they shoot to verify.
[ QUOTE ]
There are not two kinds of minutes of angle. A circle is divide into 360 degrees and each degree is divided into 60 minutes so one minute of angle is 1/60 of one degree and this equates to 1.0472" of angle at 100 yards.In other words if you drew a straight line and a secound line that angeled away from the straight line by one minute of angle then at 100 yards they would be 1.0472" apart not 1" if you are useing minutes of angle there is only one.
[/ QUOTE ]
That is correct. But what we are trying to say is that the ballistic programs aren't giving you info that directly transcribes to what your scope actually does.
YOur scope moves the reticle 1" at 100 yards and not 1.0472" which is what the program is telling you to move the turret. So when you get out there aways, that .0472 starts to add up and becomes prevalent. Rather than have everyone send in their scopes to be retro-fitted to move the actual 1.0472, it is easier to have the hackers write a program that actually <font color="red"> calculates in the same language your scope talks! </font>
Does this help clarify?
[/ QUOTE ]
I agree. I just wanted to clear up the cofussion about the two,apparently I was not clear enough.I did not intend to infer that all scopes adjusted in moa.Some scopes are advertised to have adjustments of 1/8" or1/4" adjustments and others claim to adjust in 1/8 or 1/4 moa at 100 yards.
I also agree that actual shooting at distance is the only way to know for sure.This discrepancy is why many find that thier drops are off when they shoot to verify.
Jon ,After testing more than 50 Leuopold vx 111 or vari x 111 I haven't found one that moves in True MOA no matter how they're marked on the turret. They always move 15"s when you move them 15 min.Not 15.7". The only scope I've found to move MOA was a Springfield Armory . I was just thinking that a good program could give turret numbers (SMOA)very easily for the guys who have scopes that move in inches.----7mmrhb
I think that all of the confusion is because many scope manufacturers directions explain that their scope move 1/4" per click at 100 yards,but on the turret it reads 1/4 moa.We must understand that 1 moa is 1.0472 inches per one hundred yards(1/4 moa is .2618" not .250" which is 1/4"),so if the scope moves 1" per 4 clicks then the scope adjusts in inches and not minutes of angle.The scope makers and many gunwriters add to this confusion by aserting that 1" = 1 moa.If this is not understood then elevation correction at long range will be of by a cosiderable margin.Pretend that you need 20 minutes of angle of verticale adjustment at 1000 yards and your scope adjustments are in quarters therefore 80 clicks adjustment will adjust for 200 inches of correction at 1000 yards.Now let's say your scope adjusts in minutes of angle the same 80 clicks will allow for a correct of 209.4 inches at 1000 yards.
The programs could easily be made to give correction either way. Also the scope makers could just make the scope adjust in minutes of angle as well
The programs could easily be made to give correction either way. Also the scope makers could just make the scope adjust in minutes of angle as well
goodgrouper
Well-Known Member
Of course I am saying that measuring is a must, but I was also just simply showing that knowing what your scope is doing is only half the battle. One still needs to know the error associated with the ballistic programs. /ubbthreads/images/graemlins/wink.gif
goodgrouper
Well-Known Member
Sorry for the confusion on the earlier post. You were saying that there is only one MOA and I now know what you meant. The mathematical version of MOA does not differ from the MOA we are discussing in relationship to shooting. They are one as you said. Great point.
[ QUOTE ]
The programs could easily be made to give correction either way. Also the scope makers could just make the scope adjust in minutes of angle as well
[/ QUOTE ]
Absolutely!! Lets have it. After all, we are paying for it already!
[ QUOTE ]
The programs could easily be made to give correction either way. Also the scope makers could just make the scope adjust in minutes of angle as well
[/ QUOTE ]
Absolutely!! Lets have it. After all, we are paying for it already!
JWP475, I know the MOA click values very well.I believe it was me earlier in the thread that pointed out the difference . I have been converting drop charts with a calculator for scopes that move in inches for many years.I was trying to let others be aware that might not know to check their scopes. Maybe even get someone to change a program.(fat chance)---7mmRHB
[ QUOTE ]
JWP475, I know the MOA click values very well.I believe it was me earlier in the thread that pointed out the difference . I have been converting drop charts with a calculator for scopes that move in inches for many years.I was trying to let others be aware that might not know to check their scopes. Maybe even get someone to change a program.(fat chance)---7mmRHB
[/ QUOTE ]
I was not infering that you did not understand,in fact it was post such as yours,that caused me to try and clear up my point in my earlier post as per response's I realized that I only added to the confusion by not adding enough detail
JWP475, I know the MOA click values very well.I believe it was me earlier in the thread that pointed out the difference . I have been converting drop charts with a calculator for scopes that move in inches for many years.I was trying to let others be aware that might not know to check their scopes. Maybe even get someone to change a program.(fat chance)---7mmRHB
[/ QUOTE ]
I was not infering that you did not understand,in fact it was post such as yours,that caused me to try and clear up my point in my earlier post as per response's I realized that I only added to the confusion by not adding enough detail
I read thru this thread and found a lot of agonizing about what is a MOA. This is real simple. A MOA is a "minute of angle" which is 1/60th of a degree. It is a trigonometric term and is already well defined. To eliminate the confusion, one MOA results in 1.0472 inches of deflection at 100 yards. The difference between 1.0472 and 1.0000 inches per 100 yards is no problem at short distances but it will assure a miss if you are shooting at a LaRue sized target at 1000 yards.
Why is there agony? The bench resters measure group sizes by the center to center distance of the two shots fartest apart in a group. Then they subtract the bullet diameter. Since in the early days of bench rest shooting the difference between 1.0000 and 1.0472 inches at 100 yards was negligable so someone called 1 inch at 100 yards a MOA and the rest of the story is agony. See what happens when you try to change scientific definitions. Some not too bright vendors started trying to accomodate hunters by also calling 1.000 inches at 100 yards a MOA. While the attempt to simplify things is a noble thought, it is like the government trying to change the definition of pi.
All this confusion makes the case for the advocates of the metric system. This is another trigonometric term but has the unique advantage of having a tangent value of 1/1000th. The definition of a mil radian is 1/1000th of a radian. There are 2*pi radians in a circle. If you do the math you will find that one mil radian (or just one mil) is 1 meter at 1000 meters or 1 yard (36 inches) at 1000 yards. Now that aint bad but it is a little coarse so some scope manufactures (Scmidt & Bender, NightForce) offer 1/10mil elevation adjustments for their metric scopes (0.36 inches at 100 yards). If you get into the pros and cons of the metric system vs the english system, the metric system wins hands down. There is nothing as sweet as ranging with a mil radian scope reticle.
By the way I recommend calling 1 inch per hundred yards IPHY and 1/10 mil at 100 meters CPHM. At least this clearly defines the four different sets of angular measure being used.
Hope this helps.
Why is there agony? The bench resters measure group sizes by the center to center distance of the two shots fartest apart in a group. Then they subtract the bullet diameter. Since in the early days of bench rest shooting the difference between 1.0000 and 1.0472 inches at 100 yards was negligable so someone called 1 inch at 100 yards a MOA and the rest of the story is agony. See what happens when you try to change scientific definitions. Some not too bright vendors started trying to accomodate hunters by also calling 1.000 inches at 100 yards a MOA. While the attempt to simplify things is a noble thought, it is like the government trying to change the definition of pi.
All this confusion makes the case for the advocates of the metric system. This is another trigonometric term but has the unique advantage of having a tangent value of 1/1000th. The definition of a mil radian is 1/1000th of a radian. There are 2*pi radians in a circle. If you do the math you will find that one mil radian (or just one mil) is 1 meter at 1000 meters or 1 yard (36 inches) at 1000 yards. Now that aint bad but it is a little coarse so some scope manufactures (Scmidt & Bender, NightForce) offer 1/10mil elevation adjustments for their metric scopes (0.36 inches at 100 yards). If you get into the pros and cons of the metric system vs the english system, the metric system wins hands down. There is nothing as sweet as ranging with a mil radian scope reticle.
By the way I recommend calling 1 inch per hundred yards IPHY and 1/10 mil at 100 meters CPHM. At least this clearly defines the four different sets of angular measure being used.
Hope this helps.
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