Rifle Scopes Mrad IS Meteric

[Buckeye308]

.1 Mrad = 1cm @ 100m
.2 Mrad = 2cm @ 100m
.3 Mrad = 3cm @ 100m
....
1 Mrad = 10cm @ 100m


1Mrad @ 475m = 47.5cm

If this doesnt seem easier than MOA math, ... ok. Lets agree to disagree.

.1 Mrad = .1Mrad @ any distance
.2 Mrad = .2Mrad @ any distance
.3 Mrad = .3Mrad @ any distance
....
1 Mrad = 1 Mrad @ any distance

If I shoot and see that I am .4 Mrad low, I dial in .4Mrad clicks of Doom and I am ready. Who cares how much .4Mrad is at "X" distance. As for ranging, yea I do basic ranging with my scope but I have a range finder for that reason.

 

[Crus75]

uh, what was the question again??

 

[Graham]

Sometimes I quote myself and Lindy at the same time:

At a distance of 10011100010000 parsecs (binary), one milliradian subtends an arc whose length is 1010 parsecs (binary). How is that metric?

 

[Buckeye308]

...and if I slice a foot into 10 sections, I have 1.2 inch sections....
(Slicing something by 10, 100, etc does not make that part of something metric.)

No that makes you a Surveyor, we use feet, tenths, hundredeths, all not metric

 

[Crus75]

The fact early US Scope makers and training focused around the linear distance at range does not make it valid or correct. Just because that is how they "used" to do it, or that was how you were taught doesn't make it right.

People are very adaptable and will adjust, doesn't make it any less limiting in practical application simply because we made due.

They recognized the need for angles, and the benefit of it, then immediately turned away from that very method to relate the distance via a linear measurement. Linear discussions and distances have no real place within the scope, it should only apply to the distance in terms of range, not any part of the solution for either range or wind. The Angle is universally superior to saying 1 (anything) @ 100, 2 @ 200, 3 @ 300... this cause a lot of confusion, even with people who think they understand it.

Anyone can succeed when on their range shooting alone, the difference comes into play when you have a situation beyond your making or control. I have seen many a person who used a mix of MOA & IPHY on their home range fall apart when taken out of their comfort zone and that is a result of the errors built into the system. It's a big fudge factor from the start, and only compounds at distance because the fudge factor was never intended to shoot beyond short ranges or was used only KD Ranges where it really didn't matter. If you have a vertical fudge factor in the target of 4 MOA or more as many target will you'll never see the errors of your ways. Also, if you are shooting on a KD Range (even with a sub moa bullseye) you are zeroing for that range and it makes no difference what the answer to the range is. If the routine is always to dial the same number you might as well call it 8 for 800, 9 for 900 and never used any unit of measurement.

The MOA is dead, or at least should be allowed to die...

There is no reason to use it in shooting, there is no reason to incorporate it in a scope and there is no effective way to modify it beyond IPHY. Even that should really only be used for KD Course shooting. When it comes to using the scope and reticle in combination for tactical shooting, even hunting or any other form of UKD it should be shunned as too sloppy and too ineffective for extended use. The idea we "think" in inches is a ridiculous one and doesn't play out. Effective shooters don't think in linear terms, they read the ruler and adjust to exactly what they see. If the first thing that pops in your head is, linear, 1@ 100, 2@ 200, etc, that is clue you are doing it wrong. There is no reason to "think" about it that way at all.

1.047 does not divide effectively by anything. They have difficultly machining it in the turrets, they have taken to shorting it to the point you have to map it. If you own a MOA based scope and you haven't tested it completely, the odds are against you from the start. Same with the reticle. They find it much easier to make a reticle MOA based then give you an IPHY turret. Big mistake. Also as noted there is not Standardized subtension across manufacturers, no two reticles are exactly the same will have a defining reference point like Mils do. Not all MOA reticles have a 1 MOA reference, or two, etc, and not all MOA / IPHY are the same either, 1/8th, 1/4th, 1/2, 1" all exist in current offerings. Mils it is .1 with a few that offer .05 simply because people believe they need that close to 1/8th adjustment for accuracy. But practically speaking all mil based scopes have 1. turrets with 1 mil in the reticle. There is a standard, the fact a few chose to deviate doesn't matter in the big picture.

Stop supporting the idea of the MOA in a reticle and let it die, it's outlived it's usefulness

Lowlight - I think your right on, but this thread's very existance is fact that people don't get the big picture and why they were relegated to MOA use in the first place. If they can't interpret it for what it is, then that's not anyone's fault but their own...

 

[okrebel92]

I think it's funny all of this started because someone discovered Wikipedia... which is never, ever, EVER wrong about anything or anyone.... and only certified specialists in a given field of study are allowed o post there and fuck-tards and mall-ninjas living in their moms basement aren't able to change things.

 

[KUSA]

The dipshit that came up with inches, feet, yards, and miles was a true idiot. Its almost like a cruel joke that was played on everyone who was taught it since its inception. Why would anyone want to make a system that was not decimal based? I am now a prisoner of it. After 43 years of living it is difficult to get a feel for anything else.

 

[LastShot300]

The fact early US Scope makers and training focused around the linear distance at range does not make it valid or correct. Just because that is how they "used" to do it, or that was how you were taught doesn't make it right.

People are very adaptable and will adjust, doesn't make it any less limiting in practical application simply because we made due.

They recognized the need for angles, and the benefit of it, then immediately turned away from that very method to relate the distance via a linear measurement. Linear discussions and distances have no real place within the scope, it should only apply to the distance in terms of range, not any part of the solution for either range or wind. The Angle is universally superior to saying 1 (anything) @ 100, 2 @ 200, 3 @ 300... this cause a lot of confusion, even with people who think they understand it.

Anyone can succeed when on their range shooting alone, the difference comes into play when you have a situation beyond your making or control. I have seen many a person who used a mix of MOA & IPHY on their home range fall apart when taken out of their comfort zone and that is a result of the errors built into the system. It's a big fudge factor from the start, and only compounds at distance because the fudge factor was never intended to shoot beyond short ranges or was used only KD Ranges where it really didn't matter. If you have a vertical fudge factor in the target of 4 MOA or more as many target will you'll never see the errors of your ways. Also, if you are shooting on a KD Range (even with a sub moa bullseye) you are zeroing for that range and it makes no difference what the answer to the range is. If the routine is always to dial the same number you might as well call it 8 for 800, 9 for 900 and never used any unit of measurement.

The MOA is dead, or at least should be allowed to die...

There is no reason to use it in shooting, there is no reason to incorporate it in a scope and there is no effective way to modify it beyond IPHY. Even that should really only be used for KD Course shooting. When it comes to using the scope and reticle in combination for tactical shooting, even hunting or any other form of UKD it should be shunned as too sloppy and too ineffective for extended use. The idea we "think" in inches is a ridiculous one and doesn't play out. Effective shooters don't think in linear terms, they read the ruler and adjust to exactly what they see. If the first thing that pops in your head is, linear, 1@ 100, 2@ 200, etc, that is clue you are doing it wrong. There is no reason to "think" about it that way at all.

1.047 does not divide effectively by anything. They have difficultly machining it in the turrets, they have taken to shorting it to the point you have to map it. If you own a MOA based scope and you haven't tested it completely, the odds are against you from the start. Same with the reticle. They find it much easier to make a reticle MOA based then give you an IPHY turret. Big mistake. Also as noted there is not Standardized subtension across manufacturers, no two reticles are exactly the same will have a defining reference point like Mils do. Not all MOA reticles have a 1 MOA reference, or two, etc, and not all MOA / IPHY are the same either, 1/8th, 1/4th, 1/2, 1" all exist in current offerings. Mils it is .1 with a few that offer .05 simply because people believe they need that close to 1/8th adjustment for accuracy. But practically speaking all mil based scopes have 1. turrets with 1 mil in the reticle. There is a standard, the fact a few chose to deviate doesn't matter in the big picture.

Stop supporting the idea of the MOA in a reticle and let it die, it's outlived it's usefulness

Well said ...Amen!

 

[Nebula]

I'm a new guy to long range stuff, but I've worked in engineering and understand how radians and degrees/minutes/seconds work. What I don't understand is why there are so many damn scope manufacturers out there like to use a mix of the two, or use stuff like BDC reticules. Give me matching reticule and adjustment in any single given measurement at the least, and leave the BDC reticules to the one gun & cartridge it's designed for. It's especially evident on the lower-mid class scopes, where mil/mil scopes are few and far between it seems. It's as if they use it to push to the higher tier/price scopes. Which I'm sure are great and all, but much like I wouldn't need a Ferrari my first time out on a race track, I don't need it on my first legitimate long range rifle (especially one that will be used for hunting.)

 

[Pinecone]

If I shoot and see that I am .4 Mrad low, I dial in .4Mrad clicks of Doom and I am ready. Who cares how much .4Mrad is at "X" distance. As for ranging, yea I do basic ranging with my scope but I have a range finder for that reason.

And if you shoot and are .5 MOA low and dial in .5MOA and you are ready.

As long with both reticle and turrets match, not a big deal.

Angles are angles.

Radians or degrees.

 

[Kevlars]

OMG. You all are making it so difficult. LL you were right this thread only serves to confuse people.

 

[Reaper130]

How many folks here are honestly shooting with an MOA/MOA optic?

I'd be very surprised to see many hands being raised, just based on how drastic the optic market has changed in the past 4 or 5 years in terms of matching turrets and MRAD's becoming vastly more popular. Less math is a good thing when shooting for the average person.

 

[Bounce]

Rob

His reticle will be TRUE MOA and his Turrets will be IPHY

Depending on who makes it, almost guaranteed.

Actually, as it turns out, and contrary to my earlier post, my next scope will be a March mil/mil. Since MOA is dead, gonna die, or ought to die, I don't wannabe left in a reticle cemetery. That said, degrees and angles make my head hurt.
Skip

 

[kraigWY]

Since MOA is dead, gonna die

Not likely.

 

[E. Bryant]

Nonsense. If I slice an orange into 10 slices, it's not metric. It's still (part of) an orange.... and a damn good juicy one at that.

But what if I take an apple and slice it into 10 slices - how would that compare to your example?

 

[Graham]

But what if I take an apple and slice it into 10 slices - how would that compare to your example?

That's an easy one: Everyone knows that apples are MOA.

 

[dcjs]

Everyone knows that apples are MOA.

Only if you slice them into 60 pieces (minutes of apple).

 

[HillbillyfromAL]

Only "Gala" apples are MOA

 

[Snake-Eyes]

"Mrad IS Meteric"? Hmmm, only if 'Meteric' means 'NOT metric'...

Of course, we could just add it to the Wiktionary, then it'd be true, right?

However, it IS in the Urban Dictionary:
Urban Dictionary

Long live mil/mil FFP...

For those who still insist on bizarre conversions instead of accepting a simple 1/1000th ratio of whatever measurement you prefer:

 

[sib1948]

Well said ...Amen!

The fact early US Scope makers and training focused around the linear distance at range does not make it valid or correct. Just because that is how they "used" to do it, or that was how you were taught doesn't make it right.

People are very adaptable and will adjust, doesn't make it any less limiting in practical application simply because we made due.

They recognized the need for angles, and the benefit of it, then immediately turned away from that very method to relate the distance via a linear measurement. Linear discussions and distances have no real place within the scope, it should only apply to the distance in terms of range, not any part of the solution for either range or wind. The Angle is universally superior to saying 1 (anything) @ 100, 2 @ 200, 3 @ 300... this cause a lot of confusion, even with people who think they understand it.

Anyone can succeed when on their range shooting alone, the difference comes into play when you have a situation beyond your making or control. I have seen many a person who used a mix of MOA & IPHY on their home range fall apart when taken out of their comfort zone and that is a result of the errors built into the system. It's a big fudge factor from the start, and only compounds at distance because the fudge factor was never intended to shoot beyond short ranges or was used only KD Ranges where it really didn't matter. If you have a vertical fudge factor in the target of 4 MOA or more as many target will you'll never see the errors of your ways. Also, if you are shooting on a KD Range (even with a sub moa bullseye) you are zeroing for that range and it makes no difference what the answer to the range is. If the routine is always to dial the same number you might as well call it 8 for 800, 9 for 900 and never used any unit of measurement.

The MOA is dead, or at least should be allowed to die...

There is no reason to use it in shooting, there is no reason to incorporate it in a scope and there is no effective way to modify it beyond IPHY. Even that should really only be used for KD Course shooting. When it comes to using the scope and reticle in combination for tactical shooting, even hunting or any other form of UKD it should be shunned as too sloppy and too ineffective for extended use. The idea we "think" in inches is a ridiculous one and doesn't play out. Effective shooters don't think in linear terms, they read the ruler and adjust to exactly what they see. If the first thing that pops in your head is, linear, 1@ 100, 2@ 200, etc, that is clue you are doing it wrong. There is no reason to "think" about it that way at all.

1.047 does not divide effectively by anything. They have difficultly machining it in the turrets, they have taken to shorting it to the point you have to map it. If you own a MOA based scope and you haven't tested it completely, the odds are against you from the start. Same with the reticle. They find it much easier to make a reticle MOA based then give you an IPHY turret. Big mistake. Also as noted there is not Standardized subtension across manufacturers, no two reticles are exactly the same will have a defining reference point like Mils do. Not all MOA reticles have a 1 MOA reference, or two, etc, and not all MOA / IPHY are the same either, 1/8th, 1/4th, 1/2, 1" all exist in current offerings. Mils it is .1 with a few that offer .05 simply because people believe they need that close to 1/8th adjustment for accuracy. But practically speaking all mil based scopes have 1. turrets with 1 mil in the reticle. There is a standard, the fact a few chose to deviate doesn't matter in the big picture.

Stop supporting the idea of the MOA in a reticle and let it die, it's outlived it's usefulness

I love a good debate, but Lowlight nailed it with this quote. If you don't get it yet, go to the blackboard and write this 100 times.
MOA is DEAD or a least should be, if you want to make the most of your LR shooting endeavors at known or unknown distances.
Give it up!

 

[Chiller]

That's it. People that know how to use them see these posts and laugh. It's ridiculous.




Why even translate it to a linear measurement? No need at all. .1 mil is .1 mil at 50 yards/meters or 1000 yards/meters.

Because people can visualize an inch or a foot. The lay person if you tell them they missed a foot right they can can visualize that.

And regardless what you have been told........this is 6 inches......

 

[Charlie Papa]

Holy crap, people! WHO GIVES A SHIT?!?!?! Y'all have fun hashing out semantics on the internet. I'm going to go shoot.

 

[Rob01]

Because people can visualize an inch or a foot. The lay person if you tell them they missed a foot right they can can visualize that.

And regardless what you have been told........this is 6 inches......

Then those people need to get off the internet and shoot more

 

[Steel-r]

Metric system uses meters... There are not two different 'yards'

My dog will certainly tell you that my yard is different than my neighbor's. However, I'm pretty sure that the electric and water companies are metric...

Sorry.

After shooting with some folks this weekend, I'm ready to switch to Mil/Mil FFP. Had trouble calculating the calls into my minute dials. HOWEVER, if I was able to see my miss in the scope, it didn't matter, cuz I could just read the reticle & use it to hold off. At that point, it could have been in units of bananas.

 

[Pinecone]

Angles are angles are angles.

MOA or Rad are angles. Just different ways of expressing the angles, but angles. As long as two people are talking the same method, no problem. As long as the turrets and reticle are the same, no problem.

 

[Trubester88]

The only thing metric about mils is the use of the word "milli" in "milliradians".

Radians are mathematical, not metric or standard. You're trying to essentially argue whether pi is metric or not.

next topic..

True, radians are mathematical. But can one argue the fact that just like the metric system with mm, cm, dm, and meters with the simple conversions, that with milliradians at any distance in meters are so easy to convert directly into the metric system?

1 mr @ 100 meters = 10cm. Oh wow that was easy!
1 MOA @ 100 yards? 1.024"... not nearly as simple.

5 mr @ 1000 meters = 5 meters
5 MOA @ 1000 meter = 55.12"

Are you saying that just happens by chance that using radians with the metric system is so simple to convert? Just like... the entire metric system!

 

[dcjs]

Are you saying that just happens by chance that using radians with the metric system is so simple to convert?

Hint: "Milli-" is a decimal prefix.

 

[Trubester88]

Hint: "Milli-" is a decimal prefix.

Are you agreeing with me, or trying to tell me? I believe the system is metric or at least when the metric system was created, all of these factors came into play.

 

[ridenrunwv]

True, radians are mathematical. But can one argue the fact that just like the metric system with mm, cm, dm, and meters with the simple conversions, that with milliradians at any distance in meters are so easy to convert directly into the metric system?

1 mr @ 100 meters = 10cm. Oh wow that was easy!
1 MOA @ 100 yards? 1.024"... not nearly as simple.

5 mr @ 1000 meters = 5 meters
5 MOA @ 1000 meter = 55.12"

Are you saying that just happens by chance that using radians with the metric system is so simple to convert? Just like... the entire metric system!

1 mr @ 100 yards = .1 yards
5 mr @ 1000 yards = 5 yards

The metric system isn't what makes the conversion from mils so simple but the fact that people using the metric system are used to thinking in 1/10 and 1/100 of a meter.

People just aren't used to thinking about 1/10th yards but MRAD makes the conversion just as simple that way.

 

[Trubester88]

1 mr @ 100 yards = .1 yards
5 mr @ 1000 yards = 5 yards

The metric system isn't what makes the conversion from mils so simple but the fact that people using the metric system are used to thinking in 1/10 and 1/100 of a meter.

People just aren't used to thinking about 1/10th yards but MRAD makes the conversion just as simple that way.

True, everyone likes to convert to the smallest unit of measurment. Just happens that the metric system is built upon numbers devisable by 10, 100, 1000 etc. Of course 1/10 of 1 yard is 3.6", but it is rough quickly calculating different measurements at greater distances.

 

[exx1976]

True, everyone likes to convert to the smallest unit of measurment. Just happens that the metric system is built upon numbers devisable by 10, 100, 1000 etc. Of course 1/10 of 1 yard is 3.6", but it is rough quickly calculating different measurements at greater distances.

What you say may be accurate, indeed, but it does not change the fact that mils are not metric. Radians are a mathematical principle, just like sine, cosine, tangent, secant, etc. The fact that you choose to plug in mm or cm instead of inches or feet does not change the fact that in both the US and the UK a circle has 360 degrees in it, and a triangle has 180 degrees.

Can we please be finished with this ridiculous thread now?

 

[ridenrunwv]

What you say may be accurate, indeed, but it does not change the fact that mils are not metric. Radians are a mathematical principle, just like sine, cosine, tangent, secant, etc. The fact that you choose to plug in mm or cm instead of inches or feet does not change the fact that in both the US and the UK a circle has 360 degrees in it, and a triangle has 180 degrees.

Can we please be finished with this ridiculous thread now?

Agreed... It's just an angular measurement used with any unit of distance. Could create a unit of distance called Jimbob and 1 mr at 100 Jimbobs is still equivalent to .1 Jimbobs

 

[tylerw02]

Because people can visualize an inch or a foot. The lay person if you tell them they missed a foot right they can can visualize that.

This is one of my biggest pet peeves. I get so frustrated when spotting for somebody that insists on converting the angular measurement to a linear measurement then back to an angular measurement. It doesn't matter what my freaking estimate in inches you missed by is because without measuring, its useless----there is no need to visualize! Use the freaking reticle in your scope, it measures for you for pete's sake!

 

[ridenrunwv]

This is one of my biggest pet peeves. I get so frustrated when spotting for somebody that insists on converting the angular measurement to a linear measurement then back to an angular measurement. It doesn't matter what my freaking estimate in inches you missed by is because without measuring, its useless----there is no need to visualize! Use the freaking reticle in your scope, it measures for you for pete's sake!

Absolutely... Conversions and metric vs whatever aside no matter what distance missing by a mil is missing by a mil. There is no need to convert and guess on sizes. If POI is a mil low come up a mil.

This thread is going nowhere because most shooters/spotters use mils as easy communication and could care less about inches or centimeters when shooting and correcting after a miss.

 

[JFComfort]

How many folks here are honestly shooting with an MOA/MOA optic?

I'd be very surprised to see many hands being raised, just based on how drastic the optic market has changed in the past 4 or 5 years in terms of matching turrets and MRAD's becoming vastly more popular. Less math is a good thing when shooting for the average person.

I have one of each, a USO LR-17 MOA/MOA and a USO ER-25 MRAD/MRAD. This whole argument is 6 one way, half dozen the other.

I do believe LL has a point, if their is no standard for TMOA or if companies are mixing TMOA and SMOA reticles/turrets. A MOA is a MOA at any distance just like a MRAD is a MRAD at any distance....

 

[Rob01]

This is one of my biggest pet peeves. I get so frustrated when spotting for somebody that insists on converting the angular measurement to a linear measurement then back to an angular measurement. It doesn't matter what my freaking estimate in inches you missed by is because without measuring, its useless----there is no need to visualize! Use the freaking reticle in your scope, it measures for you for pete's sake!

Exactly. As I said earlier in this thread in response to someone talking about conversions.

Why even translate it to a linear measurement? No need at all. .1 mil is .1 mil at 50 yards/meters or 1000 yards/meters.

 

[tylerw02]

I keep thinking someday its going to click for some people, but they just never get it. Its sad, really.

 

[sharac]

I think natural tendency that when in trouble revert to your comfortable way of thinking. Coming from Europe and being "metric" since the first time i measured my dick there are still plenty of people with problems using rads or any other angular measure. In the army in the basics (orientation and range estimation) there was really a lot of work to get some people to understand mils and how to calculate distance to that telephone pole over the valley not to mention the estimations with your fingers and we're all "metric". Later when i was with mortars, mils where just about everything there were even more problems (soviet block 6k/circle irony being this is more "yard" friendly when doing conversions and also for those with russian optics should consider this if they use conversions to minutes as 1 degree = 16.6.."russian mil" but this has almost nothing to do with scope use and it only contributes to confusion ). I guess it's easier for people to calculate using something they're used to (meters, yards) then to practice and spend some effort (same with equipment easier to buy latest gizmo or have that custom rifle fitted with every trinket imaginable than to loose that beer belly or lie down and practice).

 

[TiroFijo]

Don't worry, is a weekly occurrence since at least 10 years now...

 

[bbrah]

Just ran across this thread while researching "Russian Mils" on an IOR compass I just picked up. I realize that it's an old thread, but I just had to chime in.

the metric system has inherent advantages in engineering and science, and again is the world STANDARD

I've heard this metric/US argument at least a dozen times over my life and my brother who is an engineer for Bell helicopters offered me the best explanation I've yet heard to justify the continued existence of the “American/Imperial/SAE" system.

The U.S. system has at least one real advantage over the metric system. In machining processes the "thou" or thousandth of an inch is the standard measuring unit for mechanical tolerances and the like. Most common precision manufacturing tolerances are held to within a couple of thousandths. "Just use millimeters or some fraction thereof," TiroFijo might say. Great! However there is not a decimal fraction of a millimeter that is the appropriate scale. In other words, 0.1mm is too coarse and 0.01mm is too fine for most machining operations.

One-thousandth of an inch is equal to 0.0254 of a millimeter (1mm = 39.37 thousandths of an inch). Therefore 1/10 of a mm is equal to ~ 4 thou (3.937 thousandths) and 1/100 of a millimeter is equal to ~0.4 thou. Essentially That's why American aerospace companies like Boeing and even European ones like Airbus use (or at least reference on their drawings) dimensional tolerances in 1/1000 inch increments.

This is just one example of a measuring system being more usable than another. There is another example with which most of us are intimately familiar: grains for measuring powder and bullets.

A "grain" is equal to 64.79891 milligrams or 1/7000 of a pound, yet ammunition manufacturers WORLDWIDE, regardless of their country's adoption of the metric system, continue to measure their bullet weights and powder charges in grains rather than grams, ounces, or fractions of either. This is simply because the scale of the unit itself is easier (and thus more accurate) to use. If I'm loading up some .308 (um, 7.62 x 51mm) it's a hell of a lot easier to measure a powder charge in tenths of a grains (e.g. 44.6gr) than it is to measure in hundredths of grams (e.g. 2.89g). Even measured in hundredths, the coarseness of the gram unit itself can generate unweildly results and is prone to human or mechanical error.

My standard load for 150gr FMJ using WC846 is 44.6 grains (2.89 grams). The difference between cartridges loaded with 44.6 grains and 44.7 grains of powder is so small, that it is unlikely to be noticed (and would certainly fall within the Standard Deviation for velocity of “identical” cartridges). However the difference between cartridges loaded with 2.89 grams and 2.90 grams of powder (2.89g = 44.6gr while 2.90g = 44.754gr), amounts to about 150 fps. Certainly enough to make a difference at longer ranges.

The metric system is nice for commerce, or when you need to be able to convert units quickly, but just because it is “universally” accepted doesn't mean metric units are best for measuring every task. We humans have a knack for inventing systems to meet specific challenges. Most of our "common" measurements came about in response to the need to be able to measure things quickly within reasonable tolerances with the tools at hand. The "foot" is still roughly equivalent in length to a man's foot in a shoe, the "inch" is still roughly the width of a man's thumb, and most adult males are closer to 6' tall rather than 2m. The units in the metric system were developed through extrapolation and/or division of a much larger unit and as such do not necessarily scale well. That's why, decades after the rest of the world switched, we're still clinging to our arbitrary archaic measuring units.

-BRAH

Oh, and don't even get me started about "mils." Besides the old degree-minute-second, divisions of the circle there are at least three different practical systems to measure the 6283.185 mrad divisions of a circle, but guess which one is "universally" accepted. Yep, the American one (6400 verses 6300-Sweden and 6000 USSR).

 

[S12A]

From the mind of a guy who needs to get out more...

^ this

who gives a shit really, does it being metric or imperial impact on how you use it or understand it? if it does then you must have some pretty convoluted and confusing shit going on up top!

 

[Bender]

Mrad IS Meteric

I first thought MOA was the easiest to understand, but then I pulled my head out of my ass and saw the Mil for what it was and never looked back. But this thread of useless information was quite fun to read.

I shot next to a clown at the range once that "could shoot an antelope in the eye at a mile"............anyway I asked him if he wanted corrections given while he sighted in his rifle with a Loopy MK4 mil dot scope. I was watching with my SWFA fixed 10x and told him he was right 1.5 mils on his first shot, he said ok...... How many inches is that? I told him it was only 1.5 mils, just dial that in.... He then was trying to figure the inches off and then how many yards away the target... Then pulled out his phone to use as a calculator.... Mumbling under his breath.....

I got a "phone call" and had to leave. I have just decided there are those who are to stubborn, stupid or proud to understand. Oh well.

 

[aam]

"My standard load for 150gr FMJ using WC846 is 44.6 grains (2.89 grams). The difference between cartridges loaded with 44.6 grains and 44.7 grains of powder is so small, that it is unlikely to be noticed (and would certainly fall within the Standard Deviation for velocity of “identical” cartridges). However the difference between cartridges loaded with 2.89 grams and 2.90 grams of powder (2.89g = 44.6gr while 2.90g = 44.754gr), amounts to about 150 fps. Certainly enough to make a difference at longer ranges."


(2.89g = 44.6gr while 2.90g = 44.754gr). I don't think this small amount will give you 150 fps difference. You're only looking at 0.15 grains of powder, ( 0.1½ )

 

[Pinecone]

"My standard load for 150gr FMJ using WC846 is 44.6 grains (2.89 grams). The difference between cartridges loaded with 44.6 grains and 44.7 grains of powder is so small, that it is unlikely to be noticed (and would certainly fall within the Standard Deviation for velocity of “identical” cartridges). However the difference between cartridges loaded with 2.89 grams and 2.90 grams of powder (2.89g = 44.6gr while 2.90g = 44.754gr), amounts to about 150 fps. Certainly enough to make a difference at longer ranges."


(2.89g = 44.6gr while 2.90g = 44.754gr). I don't think this small amount will give you 150 fps difference. You're only looking at 0.15 grains of powder, ( 0.1½ )

Or, if 0.15 grains of powder gives a 150 fps change in velocity, then why is a 0.10 grain difference immaterial???? It should yield a velocity change of around 100 fps (based on 0.15 giving 150 fps change).

And it is no different in holding tolerances to 25 thou mm versus 1 thou inches. Just a change in terminology.

And metric gets us away from the idiocy of fractional drill bits, plus number drill bits, PLUS letter drill bits. What is the next larger size drill bit above a 1/16" bit? Without looking.

Metric is SO much easier when converting. mm to cm to meters to kilometers versus inches to feet to yard to miles (nautical or statute?).

 

[Cardinal]

A "grain" is equal to 64.79891 milligrams or 1/7000 of a pound, yet ammunition manufacturers WORLDWIDE, regardless of their country's adoption of the metric system, continue to measure their bullet weights and powder charges in grains rather than grams, ounces, or fractions of either.
.

Slightly inaccurate, bullet weights in Europe is usually given in grams and grains. For example, my Norma catalog lists them first in grams then grains.
Powder is usually grains, though as I recall, Vectan lists grams first, then in grains.


And as aam says, a 0.15 difference in powder shouldn't give you a 150fps difference.

 

[TiroFijo]

bbrah,

All the technical drawings of guns made outside the US are metric, including rifling specs, chambers and small parts.

The base of all the "standard" modern rifle service rounds like the 30-06, 308, etc. is 12 mm (.473") because it comes from the grandaddy of them all, the 8x57 german. Some popular bulllet weights, like 124 gr for FMJ 9 mm ball comes from the metric original, 8.0 grams. And the rifling twist of 9 mm is really 1-250 mm, not 1-10". The slot separation in the popular picatinny MIL-STD-1913 rails is 10 mm, the width is 21 mm, you get the idea...

Most reloading manual in europe use grams and grains. Grains, inches measurements, and velocity in fps are indeed convenient, but the main reason they are very common is becasue of "legacy" issues: most people who reload are from the USA or use tables and equipment made there.

0.01 grams = 0.15432 grains hardly something to worry about

I have a copy of the NATO STANAG 4090, for the 9 mm parabellum. It is from 1982, AFAIK the latest version. The drawings are both metric and inches.

 

[bbrah]

Wow, y'all sure know how to make a guy fee welcome! I count myself lucky that nobody flamed me for spelling errors. Yeah, I probably do need to get out more, but that's one of the pitfalls of working from home.

Does anyone want to argue with me that decimals or fractions are easier to calculate than whole numbers? Sure you can measure ANYTHING using ANY measuring system; I am exactly 0.0011679292929293 miles tall, but who wants to work with a number like that when there are easier and more convenient scales to use and when rounding introduces significant errors? That's why they invented scientific notation (and the metric system), to make large numbers and decimals look and function like smaller whole numbers in calculations and equations.

While converting units is a snap with the metric system, using metric units in everyday calculations is not necessarily easier. The problem lies in the fact that each metric unit of measurement is an order of magnitude smaller or larger than the next unit. Often times the things to be measured fall somewhere between two measurement units, so you end up with a result that is either needlessly precise or hopelessly inaccurate.

I tried to illustrate that point in my previous example, but apparently failed, so how about this:

If a highway lane is 12 feet wide and there are six lanes, how wide is the highway? How about if the highway lane is 3.7 meters wide? The distance is the same but the calculation is easier using the measurement scale originally designed for measuring such things. Which number is easier to use in calculations, 72 or 22.2? Furthermore, a rounding or measurement error of one full unit won't make much of a difference in the usability of the highway if you're measuring in feet, but could be a problem if you're measuring in meters. I realize that these kinds of errors can go both ways, but most "non-metric" measurement scales were created to measure specific things to a reasonable level of accuracy, so those units naturally "fit" the items being measured (think 1/4 carat diamond versus a 0.05 gram diamond). I agree that a lot of this is "Legacy" or tradition, but there is a reason why those measurement systems were originally developed and why they are still in use, they work.

But back to my previous example. Let me clarify. Something weighing "2.8g" on a scale accurate to within a tenth of a gram could actually weigh anywhere from 2.75g to 2.84g. Likewise something weighing "2.89g." on a scale accurate to within a hundredth of a gram could weigh anywhere from 2.885g to 2.894g.

True, the difference between 2.89 grams and 2.90 grams is only 0.01 grams (0.15 grains), but the difference between 2.8 grams and 2.9 grams is 0.1 grams or about 1.5 grains, so you could achieve acceptable loading accuracy if you had a powder scale that measures in grams to hundredths of a gram but not one that only measures to tenths of a gram.

Adding digits behind the decimal will make any metric measurement scale work, but it also adds to the confusion (as my powder weight example illustrates).

I stand by my assertion that there is little difference between 44.6 and 44.7 grains while there is a huge difference between 2.8 and 2.9 grams. Just to be clear, a tenth of a gram is equal to about 1.5 grains.

My load data books give the following start and max loads for a 150 gr. Spitzer with BLC2:
Data Source-Start charge grains/Start velocity fps-Max charge grains/Max velocity fps-Difference grains/Difference fps
Sierra-40.6/2500-48.7/2900-8.1/400
Lyman-45.0/2717-49.0/2915-4.0/198
Speer-40.0/2518-44.0/2753-4.0/235
Hodgdon-45.0/2661-48.0/2839-3.0/178

A 1.5 grain disparity in powder charges my not create a 150fps variance,but it will create enough of a variance that it falls outside the standard deviation for a string of "identical" cartridges. And this is just for the single hypothetical example listed. What would the difference in velocity be between a .45 ACP 230gr. bullet loaded with 5.0 grains and 6.5 grains of Red Dot?

I concede the point that some European ammunition manufacturers DO include bullet weights in grams. I just looked at a box of GECO 9mm in the safe and it was marked in grams, but my Silver Bear 54R was not (no doubt it was packaged specifically for us dumb Americans).

I'll also concede that many (most?) of the modern (post 1799) firearms dimensions in "inches" could be/are conversions from metric

But to get back to the original-original reason that led me to this thread, I have an IOR compass marked in "Russian" mils. Can anyone tell me if this system is used in any optics? Also can someone tell me the difference(s) in subtension from a regular (U.S.) mil-dot. I was originally disappointed when I realized what scale was on the compass, but I'm thinking about building a faux Mosin-Nagant "sniper" and might just keep the compass as an accoutrement for the rifle.

Any info would be greatly appreciated.

 

[tylerw02]

Mrad IS Meteric

You're trying way too hard, dude. Just because there is a decimal doesn't mean squat. Over that. My dad and I had this conversation about this topic and he argued as a carpenter/cabinet builder he didn't understand the metric system and couldn't visualize it. I demonstrated by cutting a string at an unspecified length to be used as a measuring device, and marked fractionally. one can still follow plan if knowing how many "strings" long something was supposed to be. Units don't matter so long as you understand them and can effectively utilize them.

 

[sscoyote]

Some have said that this topic is confusing, but I really don't think it is (entirely at least). I think it causes folks to try and understand angular systems of measure a bit better, and for some it's actually interesting. It would also be nice to simplify everything to metric, but at the snail's pace of change it probably won't be seen in our lifetimes completely, so you may as well learn to apply any angular system from simple plex to milliradian. I bet most guys here have shooting buddies that don't have a mil/mil scope--heck I'd even bet everybody here does. And for a few average Joe hunters who want to learn how to effectively apply their system in the field who bought a BDC reticle/IPHY turret he may as well learn to use what he has to the highest degree of effectiveness possible. In other words learn it all as much as you can for yourself and helping others.

 

[ahhshoot]

You guys still haven't switched over to MOB (Minute of Beer)? F'in noobs.