MERC - Maximum Effective Range Calculator

[willfrye027]

I've been playing around with this over the past few days and really enjoying it. Incredibly user friendly if you follow the directions.

I used it to answer the question of how much will I "gain" from my new long range build?

A: my tikka t3 30-06 shooting 155gr lapua scenar at 3050 fps, .9 MOA 10 shot groups.

B: the new build: tikka based fast twist 25-06 shooting 131 blackjack ACE at 3150.


I was surprised to find LESS advantage that I expected with the new build. All things being equal, it gives me another 100 yards or so at long range hunting distance, which really only shows up at 500+ yards with wind wind. Out to 500 there isn't much advantage over the trusty 30-06 until the wind get up around 10mph. If there's NO wind, I don't see a real advantage until 800 yards or so, which is farther than I would shoot an animal.

Very interesting stuff excited to see how the data compared to real shooting.

 

[mpayne]

Thanks for the info!

 

[Charles Keethler]

Kodos for great work!

 

[Gone Ballistic]

My only wish is that this would have been available years ago when I think about how many shots, target overlays accumulated, different reloads and dollars I spent trying to make the 2 mile club. This would have narrowed a lot of the learning process down so much. Thank you for having such graciousness in sharing. It downloaded OK on my laptop first time I tried it, which, at 74 was almost just as awesome as your program!

 

[speedengineer]

My only wish is that this would have been available years ago when I think about how many shots, target overlays accumulated, different reloads and dollars I spent trying to make the 2 mile club. This would have narrowed a lot of the learning process down so much. Thank you for having such graciousness in sharing. It downloaded OK on my laptop first time I tried it, which, at 74 was almost just as awesome as your program!

I've been playing around with this over the past few days and really enjoying it. Incredibly user friendly if you follow the directions.

I used it to answer the question of how much will I "gain" from my new long range build?

A: my tikka t3 30-06 shooting 155gr lapua scenar at 3050 fps, .9 MOA 10 shot groups.

B: the new build: tikka based fast twist 25-06 shooting 131 blackjack ACE at 3150.


I was surprised to find LESS advantage that I expected with the new build. All things being equal, it gives me another 100 yards or so at long range hunting distance, which really only shows up at 500+ yards with wind wind. Out to 500 there isn't much advantage over the trusty 30-06 until the wind get up around 10mph. If there's NO wind, I don't see a real advantage until 800 yards or so, which is farther than I would shoot an animal.

Very interesting stuff excited to see how the data compared to real shooting.

I'm glad you have been able to get MERC working without trouble! Willfrye027 - The study you performed is a perfect use case for MERC. It's always interesting to see how the various input variables influence the simulated performance. A 100yd benefit isn't too shabby.

I recently did a study of how much extra yardage I could get with a best-in-class BC bullet vs a copper mono. It only provided about 40 yards more range with a 10mph crosswind @ 30% uncertainty. AND, with no wind, it actually hurt performance since it has more drop and suffers due to range uncertainty!

Thanks for the feedback.
And everyone else too - please let us know how your experience with MERC goes. Look for feedback to help make the tool better and easier to use.

• Did you have any issues opening it, or with the formatting looking weird?
• Were the instructions clear - were you able to figure out how to use MERC?
• Did you encounter any other issues?
• And features you wish it had?

 

[Pro2A]

Over the past couple of months, I have been creating a Microsoft Excel based tool that calculates your probability of hitting a target. It allows study of the effects of rifle and environmental variables and uncertainties on hit percentage.

Fellow LRH member Scott B. (entoptics) convinced me that it would be worthwhile to release this tool to the shooting community. We jazzed up the user interface, design/layout, instructions, and many other details. Attached is the latest version. Hopefully you find it useful!

Note - you will need Microsoft Excel on a computer in order to run this tool. Versions of Excel for your phone will not work. The MERC Excel file is attached to this post (contained within a .zip file, as that's the only way to attach this type of file here on the forum).


Introduction to MERC - Maximum Effective Range Calculator
In a perfect world, the bullets would always leave your barrel in the direction you intended with identical velocities, and there would be no uncertainty in your wind or range estimation - you would hit your target's center with every shot. Unfortunately, we have to contend with variation and uncertainty in the real world.

This calculator lets the user specify information about their rifle and the shooting conditions, including the uncertainty in each input. The calculator applies an amount of random variation based on those specified uncertainties, and determines where the bullet would have hit. It then repeats this process for many hundreds of shots, and calculates a hit probability based on the number of hits and misses. It also plots the hit locations for the first 300 of these shots on a graph, to visually show the distribution of their impacts.


What can I use MERC for?
MERC can be used to study many shooting situations. Here are some examples to get you started:

• Comparison of one cartridge/rifle/bullet to another. For a given set of conditions, which has better hit%, etc.
• Identify the longest range you would be comfortable hunting at, given a specific set of conditions and uncertainties.
• Estimating what hit rates to expect for a yardage that's farther than you've shot before.
• Comprehend how errors in your scope zero affect hit probability.
• How much does "x" variable matter. For example, does a 0.5 MOA rifle help my hit% for my shooting scenario? How about StdDev in MV?
• How accurately do you need to estimate range and wind in order to have consistent hits?
• For a desired hit percentage, how much extra range does using a higher BC bullet provide?
• Understanding how wind angle uncertainty can cause groups that aren't centered around your point of aim.

Example screenshot from the calculator:
View attachment 210491

Applied Ballistics has this tool known as WEZ.....Weapon Employment Zone calculator.

 

[rem.xp100]

Applied Ballistics has this tool known as WEZ.....Weapon Employment Zone calculator.

AB does great work so I in no way want to put them down but I believe that WEZ is $200........they do throw in a book for free IF you click the box though.

 

[speedengineer]

I wanted to demonstrate the effect of each one of the uncertainty parameters individually. It is helpful to understand how each parameter is contributing to your shot dispersion at range. For this analysis, I am using a 6.5 PRC with 143 ELDX shooting at a 6.282" diameter target (1 MOA at 600 yards). Edit (I might not have used the 6.5 PRC trajectory data for this example...might be 30-06. But, the same trends apply, despite the label on the plots. I also didn't update the 'title' field for each plot. But just read the descriptions above each image...

MERC is able to consider uncertainty in five parameters:

• Rifle (and shooter) Precision (MOA)
• Muzzle Velocity
• Range Estimation
• Wind Speed Estimation
• Wind Angle Estimation

First, if you set all of the above uncertainties to zero, then all of your shots will hit exactly at your point of aim! You'll calculate a 100% hit probability, obviously.

Second, if you set only the "Rifle (and shooter) Precision" value to be 1 MOA, you'll get 90% hits at 600 yards. This is because we defined a 1MOA rifle as hitting a 1MOA target 9 out of 10 shots. Notice the hit distribution plot shows a scattered hit pattern that is centered around your point of aim.

Next, let's set the Rifle/Shooter Precision value back to zero. Actually, let's put it at 0.05 MOA (almost zero) since it'll make viewing the shot dispersion of the subsequent examples easier (shots won't all be on a single line).

Now, let's specify 10fps of muzzle velocity standard deviation. In this situation, with no wind, MVSD causes vertical dispersion on your target.

Now lets add in some 10mph crosswind from right to left. BUT, still zero uncertainty in wind speed estimation and wind angle estimation. With the addition of a crosswind, you can observe that SDMV results in hits that trend at an angle on the target! What this is showing is that when the rifle has a round that fires at a faster velocity than nominal, it hits the target high (less drop than anticipated) but it also hits that target to the upwind side! Since it was traveling faster, it experienced less wind drift than you held for. Rounds that leave the muzzle at a lower velocity than nominal will hit low, and be blown farther to the downwind side!

Set MVSD back to zero, and specify 10 yards of range uncertainty. Much like MVSD, range uncertainty causes vertical dispersion of the impact points. When the actual range is different from the range that you dialed for, your shot will hit the target either high or low.

...To be continued in the next post. I guess only 10 image attachments are allowed per post!

 

[speedengineer]

...continued...

Ok, set Range uncertainty back to zero. Now let's set wind speed uncertainty to 20%.
Because the wind speed for each shot is different than the nominal wind speed that you hold for, your hits will spread out horizontally.

Let's set wind speed uncertainty back to zero, and set wind angle uncertainty to 25 degrees.
Because we are shooting in a 10mph 'full value' crosswind, any error/deviation in wind direction from that 90 degrees results in LESS crosswind speed than the shooter held for. Example, if wind direction uncertainty for a particular shot was 20 degrees less than actual, then the wind angle used for the shot would be 70 degrees, which will result in less crosswind speed than 10mph. Actually for this case, it would be 9.4 mph. Because of this effect, and wind angle uncertainty with a crosswind will results in shots impacting the target only towards the upwind side!!! Very interesting to note this, as it means that your groupings can become non-centered around your point of aim when shooting in a crosswind situation with variable wind direction! You may even attain a better hit percentage by aiming slightly downwind of your target center. You can experiment with this by entering a 'horizontal scope error' value into MERC.

Lastly, let's combine all of the above mentioned uncertainties together. This shows the total combined effect of everything acting together to affect your rifles accuracy, hit locations, and resulting hit percentage!
1 MOA
10fps MVSD
10yd Range Uncertainty
20% Wind Speed Uncertainty
25 degree Wind Angle Uncertainty

 

[Nunu]

Over the past couple of months, I have been creating a Microsoft Excel based tool that calculates your probability of hitting a target. It allows study of the effects of rifle and environmental variables and uncertainties on hit percentage.

Fellow LRH member Scott B. (entoptics) convinced me that it would be worthwhile to release this tool to the shooting community. We jazzed up the user interface, design/layout, instructions, and many other details. Attached is the latest version. Hopefully you find it useful!

Note - you will need Microsoft Excel on a computer in order to run this tool. Versions of Excel for your phone will not work. The MERC Excel file is attached to this post (contained within a .zip file, as that's the only way to attach this type of file here on the forum).


Introduction to MERC - Maximum Effective Range Calculator
In a perfect world, the bullets would always leave your barrel in the direction you intended with identical velocities, and there would be no uncertainty in your wind or range estimation - you would hit your target's center with every shot. Unfortunately, we have to contend with variation and uncertainty in the real world.

This calculator lets the user specify information about their rifle and the shooting conditions, including the uncertainty in each input. The calculator applies an amount of random variation based on those specified uncertainties, and determines where the bullet would have hit. It then repeats this process for many hundreds of shots, and calculates a hit probability based on the number of hits and misses. It also plots the hit locations for the first 300 of these shots on a graph, to visually show the distribution of their impacts.


What can I use MERC for?
MERC can be used to study many shooting situations. Here are some examples to get you started:

• Comparison of one cartridge/rifle/bullet to another. For a given set of conditions, which has better hit%, etc.
• Identify the longest range you would be comfortable hunting at, given a specific set of conditions and uncertainties.
• Estimating what hit rates to expect for a yardage that's farther than you've shot before.
• Comprehend how errors in your scope zero affect hit probability.
• How much does "x" variable matter. For example, does a 0.5 MOA rifle help my hit% for my shooting scenario? How about StdDev in MV?
• How accurately do you need to estimate range and wind in order to have consistent hits?
• For a desired hit percentage, how much extra range does using a higher BC bullet provide?
• Understanding how wind angle uncertainty can cause groups that aren't centered around your point of aim.

Example screenshot from the calculator:
View attachment 210491

Over the past couple of months, I have been creating a Microsoft Excel based tool that calculates your probability of hitting a target. It allows study of the effects of rifle and environmental variables and uncertainties on hit percentage.

Fellow LRH member Scott B. (entoptics) convinced me that it would be worthwhile to release this tool to the shooting community. We jazzed up the user interface, design/layout, instructions, and many other details. Attached is the latest version. Hopefully you find it useful!

Note - you will need Microsoft Excel on a computer in order to run this tool. Versions of Excel for your phone will not work. The MERC Excel file is attached to this post (contained within a .zip file, as that's the only way to attach this type of file here on the forum).


Introduction to MERC - Maximum Effective Range Calculator
In a perfect world, the bullets would always leave your barrel in the direction you intended with identical velocities, and there would be no uncertainty in your wind or range estimation - you would hit your target's center with every shot. Unfortunately, we have to contend with variation and uncertainty in the real world.

This calculator lets the user specify information about their rifle and the shooting conditions, including the uncertainty in each input. The calculator applies an amount of random variation based on those specified uncertainties, and determines where the bullet would have hit. It then repeats this process for many hundreds of shots, and calculates a hit probability based on the number of hits and misses. It also plots the hit locations for the first 300 of these shots on a graph, to visually show the distribution of their impacts.


What can I use MERC for?
MERC can be used to study many shooting situations. Here are some examples to get you started:

• Comparison of one cartridge/rifle/bullet to another. For a given set of conditions, which has better hit%, etc.
• Identify the longest range you would be comfortable hunting at, given a specific set of conditions and uncertainties.
• Estimating what hit rates to expect for a yardage that's farther than you've shot before.
• Comprehend how errors in your scope zero affect hit probability.
• How much does "x" variable matter. For example, does a 0.5 MOA rifle help my hit% for my shooting scenario? How about StdDev in MV?
• How accurately do you need to estimate range and wind in order to have consistent hits?
• For a desired hit percentage, how much extra range does using a higher BC bullet provide?
• Understanding how wind angle uncertainty can cause groups that aren't centered around your point of aim.

Example screenshot from the calculator:
View attachment 210491

 

[maaorava]

Thank you for releasing this application, and free! I really appreciate the visualisation, easy presentation of things affecting very positively to the educational value of this tool. With this kind of application normal OK shooters can develope themselves quicker to be better long range hunters. Allso less wounded animals, I quess.

 

[kiwi49]

@speedengineer
This setup you've designed looks great.
Unfortunately, I no longer have a Windows operating system in any computer.
Only Android 10 (smartphone), Apple (iPad 2, one of the Air series laptops) OS.
A shame as it I'd love to be able to use it.

 

[entoptics]

@speedengineer
This setup you've designed looks great.
Unfortunately, I no longer have a Windows operating system in any computer.
Only Android 10 (smartphone), Apple (iPad 2, one of the Air series laptops) OS.
A shame as it I'd love to be able to use it.

@kiwi49 It will work just fine on the the Mac Air laptop with OS X. Might be just a little weird formatting, but otherwise should function just fine. I recommend updating to the latest version of whatever Excel you're using. Not necessarily the latest version of Excel, jut the latest incremental updates for your version, using the "About/Help" dialogue "Check For Updates". There can be some weird bugs with Excel from sub version to sub version.

 

[kiwi49]

@kiwi49 It will work just fine on the the Mac Air laptop with OS X. Might be just a little weird formatting, but otherwise should function just fine. I recommend updating to the latest version of whatever Excel you're using. Not necessarily the latest version of Excel, jut the latest incremental updates for your version, using the "About/Help" dialogue "Check For Updates". There can be some weird bugs with Excel from sub version to sub version.

Thank you for the direction.
It's a MacBook Air laptop.
Missus had Excel on her login.
Also, cheers for the heads-up on the possible challenges regarding the various Excel version's.