Advanced Marksmanship Which mil relation formula?

[Sterling Shooter]

A. size of target in inches / mils X 25.4 = distance to target in meters, or

B. size of target in inches X 25.4 / mils = distance to target in meters

Both expressions get the same result; but, which is more compelling?

 

[Rob01]

You get the same results so neither is better or more compelling. When I use the Yard formula I do it the second way though.

 

[Sterling Shooter]

Thanks for your response. At the water cooler, most of the shooters I've talked to say they prefer A. They say it seems easier to do the math on the fly. Yet, most Military Marksmanship Manuals use B. This has made me wonder if there is some mental aspect to using one process instead of the other, as one being more brain friendly. Maybe some studies have been done to determine which gets results faster or more accurately? I know I don't know; but, while working on a marksmanship presentation I just started wondering about it.

 

[joebino55]

I prefer B. Probably because that's the way I was taught but also you will often have targets that are the same size but at different ranges. So you can do the first part of the equation and have a constant. Then every time you mil a target you just divide the constant by your mil reading instead of doing the whole thing.

 

[Rob01]

None of them are easy to do the math on the fly. They all require a calculator. The easiest way is to use a Mildot Master.

 

[Papa Zero Three]

I find "A" to be the preferred method I use. Simply from the stand point of being behind a gun, looking at the tgt and determining its size and dividing by the mils I am currently seeing in my scope and then do the multiplication. Smaller number to multiply by than the "B" method and its quicker/easier to do in my head when I don't have a calculator/cheat sheet or time, especially when I'm tired and hungry.

 

[damoncali]

I don't get it. They're the same formula.

 

[Sterling Shooter]

I don't get it. They're the same formula.

Joe and Papa offered a preference to math processing, as in a reason to divide first and multiply last or multiply first and divide last. Both views seemed well reasoned. In fact, now with these two views I will have some stimulating discussion points on the topic of range estimation for a marksmanship guide I am producing.

 

[Rob01]

I wouldn't waste too much time on it in your guide. It's a non issue. Personal preference. As I said neither will be easy to do in your head in the field and more importantly they won't be accurate if you start rounding numbers to make them easier to do in your head. Sure you can come up with some easy numbers as examples it can be done in the head but it won't work out that easy in actual use.

If under time or pressure doing things in your head is the worst way to do it. A simple tool like the Mildot Master is what to use if you want quick and easy. I carry a mildot master, calculator and I have also made a mil ranging chart which is with my data cards. Redundant methods to make sure the job is done but doing anything in my head would be way down the line. Worrying about how moving around numbers in a formula to get the same result is a waste of time in your guide in my opinion. Use it for something more important.

 

[Sterling Shooter]

This topic is a small portion of comprehensive coverage of many methods to estimate distance to target. It appears there is not a consensus here for one process being more intuitive than another; and, that has answered my question. Thank you for your informed opinion.

 

[ajwcotton]

I use method b, I like to take target size and multiply by 27.7 and get a number in advance then once I mil it i divide or just use a mil dot master...

 

[Graham]

Reticle Ranging Formulas

8541 Tactical - Mildot Range Estimation

Shooting Voodoo :: Maximizing the mil-based reticle

 

[shovelstrokeed]

When using a calculator, especially with RPN enabled, B requires no thinking and just enters as written.
eg. size of target enter 25.4 x mils /

A requires doing the division first. Storing the result in memory, enter the size and then divide by the memory. Or the use of parenthesis when entering into a spread sheet.

 

[damoncali]

When using a calculator, especially with RPN enabled, B requires no thinking and just enters as written.
eg. size of target <enter> 25.4 x mils /

A requires doing the division first. Storing the result in memory, enter the size and then divide by the memory. Or the use of parenthesis when entering into a spread sheet.

It should work either way - no parentheses required. On a normal calculator, [size] [/] [mils] [x] [25.4] [=] will get you the same answer as [size] [x] [25.4] [/] [mils] [=]

It's a distinction without a difference if you ask me.

 

[Pinecone]

As much as I like RPN, no help on this one. I was thinking you could use the stack to store the intermediate result (target size x 25.4) but that doesn't work.

So RPN or algebraic, you would store that result in a memory, and recall it for each ranging. Assuming all the targets are the same size.

So with a course with multiple targets of all the same size and using a calculator, formula A allows you to store the intermediate result and not have to do the whole calculation each time.

 

[damoncali]

As much as I like RPN, no help on this one. I was thinking you could use the stack to store the intermediate result (target size x 25.4) but that doesn't work.

So RPN or algebraic, you would store that result in a memory, and recall it for each ranging. Assuming all the targets are the same size.

So with a course with multiple targets of all the same size and using a calculator, formula A allows you to store the intermediate result and not have to do the whole calculation each time.

This is a good point. target size x 25.4 is a useful number that shouldn't be calculated more than once. It's the target size in mm. You should be thinking in metric if you want your results to be in meters. target in inches/ mil, on the other hand, is sort of useless on its own, which makes it tougher to get a grip on mentally.

So, in m head, it's really more like this - two separate calculations:

1) target in inches x 25.4 = target in mm

Done with part 1. From now on I know my target in mm. This has a benefit of also having a sanity check. You can look at the target and verify that you did the math right because you know what 550mm should look like.

2) Next calculation. target in mm / mils = range in meters.

If I do it again at a different range, I'm reverting to the metric target size and starting at step 2, not going all the way back to the imperial one.

So I guess I change my answer. I break it up into two calculations mentally. But if you insist on having one big equation, it's the same.

The concept here is to keep the numbers relating to something physical as much as possible to help stay mentally grounded and to keep things verifiable via simple observation.

 

[Darkside-Six]

I do all my multiplications first, and then divide. easier that way.....at least for me.

 

[Papa Zero Three]

As much as I like RPN, no help on this one. I was thinking you could use the stack to store the intermediate result (target size x 25.4) but that doesn't work.

So RPN or algebraic, you would store that result in a memory, and recall it for each ranging. Assuming all the targets are the same size.

So with a course with multiple targets of all the same size and using a calculator, formula A allows you to store the intermediate result and not have to do the whole calculation each time.

I'll agree, this is probably more of a personal preference issue than anything. But with that said, I think Pincone's explanation sheds more light on why I prefer "A" to "B". Aside from the math ciphering I mentioned above, the targets I am typically engaging are of the "E type silhouette" category and on a two way range, but again, that may just be me and what works best for me.

 

[Pinecone]

I am also amazed there are still people around who actually know about RPN.

I have used RPN for a LOT of years and prefer it. But I also used to work for HP, so sort of had to.

If you don't know, you can find Excalibur 2.0 fro free download. An RPN calculator for Windows.