Maximum Effective Range

[Texas]

Final result Figure 3. Maximum Effective Range.

Range Max possible miss distance 300 4.24 inches 200 2.02 inches 250 3.03 inches 248.5 3.00 inches Table 3. Iterating to find MER
So the accuracy MER condition is satisfied at a range of 248.5 yards. At this range, the 80-grain bullet retains 2231 fps (shot #3 conditions), which yields 883 ft-lbs of kinetic energy, thereby satisfying the established 500 ft-lbs MER lethality condition. If the bullet had less than the required energy, the MER would be dictated by decreasing the range until the 500 ft-lbs is satisfied, since the accuracy criteria was already met.
At the beginning of this article, I promised a component breakdown of the effects of each field variable on the trajectory. Table 4 shows the influence of each of the field variables on the original 300-yard target for shot #3.
Results Analysis
Contribution to total miss distance Shot #3 at 300 Yards Field variable Elev. Wind. Wind speed, Average 5 mph (+2mph error) -1.018” 2.51” Shooting direction, West (Coriolis acceleration) -0.23” 0” Muzzle Velocity, 2990 fps (-10 fps error) -0.16” 0” Air Density, Standard: 0.002378 Sl/ft3 (+5% = 0.002497 Sl/ft3) -0.29” 0” Other “6 degree of freedom” effects Gyroscopic drift 0” 0.40” Coriolis acceleration N/A 0.13” Total: -1.68” 3.04” Table 4. Miss distance component build up. The totals match those listed in Table 2 for shot #3.
The MER for our system is found to be 248.5 yards. So what? What can that information be used for? I mean, everything’s been based on assumptions, and the results are only valid for one particular combination of assumptions, so of what use is the answer “248.5 yards”, really? There are 2 basic ways that the preceding analysis can be applied.
8 The vertical component of the wind deflection is due to aerodynamic jump.

[Texas]

Tex:

Guess you never shot a lot of issued M-2 Ball from service grade Garands?

The reason why M-80 came into existence was because of the inefficiencies of the flat base M-2 Ball.

Can you link me to the source you may be using for these comparisons?

Thanks!

LR55

As a matter of fact, my first military issue weapon was a well worn M1. What I was referring to is Col Hatchers formula which takes into account form factor:
The Hatcher formula was originally developed in the 1930s when Major General Hatcher was working in the US Army's Ordnance department. It uses the bullet mass, velocity, frontal area of the bullet and also a 'form factor' which depends on the type of bullet. Unlike the Taylor KO factor and Thorniley Stopping Power formula which only consider the diameter of the bullet in their calculations, the Hatcher formula uses the bullet cross-sectional area in its calculation. It also uses the bullet momentum formula (we studied this three posts back) as part of its equation. Additionally, unlike all the other formulae we have studied until now, this one includes the bullet type (jacketed, non-jacketed, flat point, round nose etc.) as part of its calculation. The Hatcher Formula is:
RSP = M/(2*g) * A * F

where:
RSP = Relative Stopping Power
M = Momentum of the bullet in foot-pounds/sec (momentum = mass * velocity where mass is in lbs and velocity is in feet/sec)
g = Acceleration due to gravity in feet/sec2.
A = Frontal area of the bullet in square-inches
F = A bullet form factor that depends on the type of the bullet (see notes below)

In General Hatcher's original paper, he quotes the formula as RSP=M*A*F and prints a table of the calculated RSP values for a variety of common handgun bullet types. However, he calculates the momentum incorrectly as (kinetic energy/velocity), which ends up calculating a value of 1/2 of the actual momentum (since kinetic energy = 1/2 * mass * velocity2). He also incorrectly divides by g (acceleration due to gravity) when converting grains to lbs (no need to, because grains are a units of mass, not weight). Therefore I've updated the original formula to match the numbers on his original table and translated the equation to M/(2*g)*A*F.

The values for bullet form factor for some bullet types are defined as:
F Bullet Type
700 Fully Jacketed Pointed
900 Fully Jacketed Round Nose
1050 Fully Jacketed Flat Point
1100 Fully Jacketed Flat Point (Large flat)
1000 Lead Round Nose
1050 Lead Flat Point
1100 Lead Flat Point (Large Flat)
1000 Jacketed Softpoint (unexpanded)
1350 Jacketed Softpoint (expanded)
1250 Lead Semi-wadcutter
1100 Hollow Point (unexpanded)
1350 Hollow Point (expanded)

In an earlier version of this article, your editor had accidentally quoted the numbers as 0.7, 0.9, 1.05 etc. instead of 700, 900, 1050 etc. Apologies for that and thanks to reader Nathaniel Fitch for pointing it out in the comments below (boy, do I have egg on my face now :-))

Because the type of bullet is part of the calculation, cartridges of a particular caliber meant for a single firearm can have different RSP values because they have different bullet types. For example, for a .45 ACP bullet which has a mass of 185 grains and moving at 1000 feet/sec, we compute a RSP value of 65.661 if the bullet is a Lead Round Nose bullet, but 88.642 for a Hollow Point (expanded) bullet. How do we get these numbers, you ask?
Weight of bullet = 185 grains.
We know that 1 lb = 7000 grains.
Therefore, mass of bullet in lbs = (185/7000) = 0.0264285 lbs approximately
Velocity of the bullet = 1000 feet/sec
Therefore, Momemtum of the bullet (M) = 0.0264285 * 1000 = 26.4285 foot-lbs/sec

Diameter of the bullet = 0.451 inches. Therefore, radius of the bullet = 0.451/2 = 0.2255 inches
Frontal area of bullet (A) = pi * r2 = 3.1415927 * 0.22552 = 0.160 inches2 approximately

Now, let's assume acceleration due to gravity (g) = 32.2 feet/sec2 approximately.

For a lead round nose bullet, the form factor bullet F = 1000 from the table above.
Therefore RSP for this bullet is calculated as:
RSP = M / (2*g) * A * F = 26.4285 / (2 * 32.2) * 0.160 * 1000 = 65.661

For a hollow point (expanded) bullet, the bullet form factor F = 1350 from the table above.
Therefore RSP for this bullet is calculated as:
RSP = M / (2*g) * A * F = 26.4285 / (2 * 32.2) * 0.160 * 1350 = 88.642

Special thanks go out to reader Nathaniel Fitch for pointing out the errors in an earlier version of the article. His comments are posted below. Give him a big round of applause folks!

For self-defense purposes, the Hatcher scale recommends that the RSP be between 50-55 for effective stopping power. Values of RSP beyond 55 lead to diminishing returns, as the increase in stopping power is offset by the extra recoil strength that must be managed by the user. Per the Hatcher scale, values below 30 give a user a 30% chance of stopping the target in one shot. For values between 30 and 49, the chance of a one-shot stop rises to 50%. For values above 50, the chance of a one-shot stop rise to 90% per the Hatcher scale. Most .45 ACP cartridge types have a RSP value over 50, while 9 mm. Luger cartridges are mostly between 30 and 40. This means Hatcher's formula tends to favor .44 Magnum and .45 ACP over 9 mm. Luger for stopping power.

While the Hatcher formula does not consider factors such as bullet penetration, it is considered a fairly decent formula to determine the effectiveness of pistol ammunition.

[grayfox]

Not an expert in any of those platforms so this may be a bit too elementary, but instead of looking at a 1930's work (which doubtless was a great one for its day, and still might be useful), for today's fmj's usually flat based or slightly boat-tail, why not use available ballistics and look for a point where ke falls below some minimum... for a 16" grendel like mine with 123 bullet (admitted a match-type eldm), 2410 ft/s, the above-mentioned threshhold of 538 comes at 730-735 yds; around 24-25 MOA drop however...
A 0.450 bc- fmj would be 650 yds, 20-21 MOA drop.

no opinions on whether that terminal load has enough "stopping power", probably wounding is more like it...

[stanc]

Using the retained Kinetic Energy of that round, at 300 meters (538 ft. lbs.), as a parameter, I compare the following cartridges (all, based on velocites from 16" barrels): MK262, 77-grain, BC- 0.362, MV - 2650 fps.; .300 AAC Blackout, 125-grain, BC - 0.330, MV - 2215 fps; 6.8 SPC, 140-grain Berger VLD, BC - 0.487, MV - 2401 (NOTE: This load is approx. 5,000 PSI above the SAAMI 6.5 Grendel, and has a Cartridge Overall Length of 2.315" vs 2.260" for the Grendel); 6.5 Grendel, 144-grain Lapua FMJBT, BC - 0.636, MV - 2275 fps:

M855 - 538 ft.lbs. @ approx. 328 yards (300 meters);
MK262 - 538 ft.lbs. @ approx. 394 yards;
.300 AAC Blackout - 538 ft.lbs. @ approx. 388 yards;
6.8 SPC - 538 ft.lbs. @ approx. 760 yards;
6.5 Grendel - 538 ft.lbs. @ approx. 925 yards.

Unfortunately, that comparison has significant flaws in regard to the thread topic.

First, retained energy is not the criteria that determines maximum effective range.

Second, the 6.8 SPC and 6.5 G bullets are a lot heavier than would likely be used.*

The US Army currently uses lead-free (EPR) projectiles, as shown at right, below.




The heaviest EPR bullet feasible for 6.5 G is ~123 gr, similar to this EPR for 6.5 CT:





I think it more likely an EPR for 6.5 G would be ~105 gr, as seen in this lead-free bullet:

https://www.lehighdefense.com/264-match-solid-flash-tip-105gr-bullet

*Note the 0.449 BC of the 105 gr Flash Tip. More realistic than the 0.636 BC of the 144 gr FMJ.

[LR1955]

As a matter of fact, my first military issue weapon was a well worn M1. What I was referring to is Col Hatchers formula which takes into account form factor:
The Hatcher formula was originally developed in the 1930s when Major General Hatcher was working in the US Army's Ordnance department. It uses the bullet mass, velocity, frontal area of the bullet and also a 'form factor' which depends on the type of bullet. Unlike the Taylor KO factor and Thorniley Stopping Power formula which only consider the diameter of the bullet in their calculations, the Hatcher formula uses the bullet cross-sectional area in its calculation. It also uses the bullet momentum formula (we studied this three posts back) as part of its equation. Additionally, unlike all the other formulae we have studied until now, this one includes the bullet type (jacketed, non-jacketed, flat point, round nose etc.) as part of its calculation. The Hatcher Formula is:
RSP = M/(2*g) * A * F

where:
RSP = Relative Stopping Power
M = Momentum of the bullet in foot-pounds/sec (momentum = mass * velocity where mass is in lbs and velocity is in feet/sec)
g = Acceleration due to gravity in feet/sec2.
A = Frontal area of the bullet in square-inches
F = A bullet form factor that depends on the type of the bullet (see notes below)

In General Hatcher's original paper, he quotes the formula as RSP=M*A*F and prints a table of the calculated RSP values for a variety of common handgun bullet types. However, he calculates the momentum incorrectly as (kinetic energy/velocity), which ends up calculating a value of 1/2 of the actual momentum (since kinetic energy = 1/2 * mass * velocity2). He also incorrectly divides by g (acceleration due to gravity) when converting grains to lbs (no need to, because grains are a units of mass, not weight). Therefore I've updated the original formula to match the numbers on his original table and translated the equation to M/(2*g)*A*F.

The values for bullet form factor for some bullet types are defined as:
F Bullet Type
700 Fully Jacketed Pointed
900 Fully Jacketed Round Nose
1050 Fully Jacketed Flat Point
1100 Fully Jacketed Flat Point (Large flat)
1000 Lead Round Nose
1050 Lead Flat Point
1100 Lead Flat Point (Large Flat)
1000 Jacketed Softpoint (unexpanded)
1350 Jacketed Softpoint (expanded)
1250 Lead Semi-wadcutter
1100 Hollow Point (unexpanded)
1350 Hollow Point (expanded)

In an earlier version of this article, your editor had accidentally quoted the numbers as 0.7, 0.9, 1.05 etc. instead of 700, 900, 1050 etc. Apologies for that and thanks to reader Nathaniel Fitch for pointing it out in the comments below (boy, do I have egg on my face now :-))

Because the type of bullet is part of the calculation, cartridges of a particular caliber meant for a single firearm can have different RSP values because they have different bullet types. For example, for a .45 ACP bullet which has a mass of 185 grains and moving at 1000 feet/sec, we compute a RSP value of 65.661 if the bullet is a Lead Round Nose bullet, but 88.642 for a Hollow Point (expanded) bullet. How do we get these numbers, you ask?
Weight of bullet = 185 grains.
We know that 1 lb = 7000 grains.
Therefore, mass of bullet in lbs = (185/7000) = 0.0264285 lbs approximately
Velocity of the bullet = 1000 feet/sec
Therefore, Momemtum of the bullet (M) = 0.0264285 * 1000 = 26.4285 foot-lbs/sec

Diameter of the bullet = 0.451 inches. Therefore, radius of the bullet = 0.451/2 = 0.2255 inches
Frontal area of bullet (A) = pi * r2 = 3.1415927 * 0.22552 = 0.160 inches2 approximately

Now, let's assume acceleration due to gravity (g) = 32.2 feet/sec2 approximately.

For a lead round nose bullet, the form factor bullet F = 1000 from the table above.
Therefore RSP for this bullet is calculated as:
RSP = M / (2*g) * A * F = 26.4285 / (2 * 32.2) * 0.160 * 1000 = 65.661

For a hollow point (expanded) bullet, the bullet form factor F = 1350 from the table above.
Therefore RSP for this bullet is calculated as:
RSP = M / (2*g) * A * F = 26.4285 / (2 * 32.2) * 0.160 * 1350 = 88.642

Special thanks go out to reader Nathaniel Fitch for pointing out the errors in an earlier version of the article. His comments are posted below. Give him a big round of applause folks!

For self-defense purposes, the Hatcher scale recommends that the RSP be between 50-55 for effective stopping power. Values of RSP beyond 55 lead to diminishing returns, as the increase in stopping power is offset by the extra recoil strength that must be managed by the user. Per the Hatcher scale, values below 30 give a user a 30% chance of stopping the target in one shot. For values between 30 and 49, the chance of a one-shot stop rises to 50%. For values above 50, the chance of a one-shot stop rise to 90% per the Hatcher scale. Most .45 ACP cartridge types have a RSP value over 50, while 9 mm. Luger cartridges are mostly between 30 and 40. This means Hatcher's formula tends to favor .44 Magnum and .45 ACP over 9 mm. Luger for stopping power.

While the Hatcher formula does not consider factors such as bullet penetration, it is considered a fairly decent formula to determine the effectiveness of pistol ammunition.

Tex:

Form factor?

You think that just maybe doppler radar may be a bit better in predicting ballistic coefficients?

Form factor does not consider boat tail bullets if I recall what I read from Hatchers Notebook. It is a really poor way of measuring bullet efficiency. Sure, it was cutting edge for the 1930's but it isn't cutting edge today.

I would put my bets on my Oehler Ballistic Explorer program when calculating downrange performance over any of the calculations that were used in the 20's and 30's for ballistic predictions.

And I am way too tired to get into an argument over just how lousy issued M-2 Ball really is.

LR55

[Texas]

M2 ball sux, but penetrates well at relative close ranges

[Lemonaid]

Found this (a portion only) on wikipedia about the M24 Sniper Weapon System.
My take on it is that Maximum Effective Range as a military standard is only about accuracy. So if you want a Grendel MEF, start with an accepted standard of accuracy and you will be able to calculate or test what it's MEF is.


They were rigorously tested before being approved by Remington and the military.
A U.S. Soldier training with a M24

Accuracy: According to MIL-R-71126(AR), 3.15.7 Targeting and Accuracy, The rifle shall achieve the dispersion set forth below when fired from a Government approved machine rest. The average mean radius shall be less than or equal to the values stated below. The minimum rate of fire for conducting this test shall be three rounds per minute.[3]

Range / Average Mean Radius (AMR) — Mean Radius (MR) expresses the average distance of all the shots from the center of the shot group. AMR averages the MR of several shot groups.

200 yards (183 m): 1.3 inches
273 yards (250 m): 1.4 inches
300 yards (274 m): 1.9 inches

The radial distance from the calculated center of impact of the first target compared to the calculated center of impacts of the subsequent targets shall be less or equal to 1.086 MOA (3.3 inches @ 300 yards, 2.2 inches @ 200 yards, 2.4 inches @ 200 meters) on an average basis.

The actual rifle requirements for accuracy were .35 MOA from a machine rest and according to Major John Mende (ret.) this accuracy had to be maintained to 10,000 rounds. He stated, "Interesting side note was there was a 10,000 round requirement for the barrel to maintain the original accuracy. In fact after some 10,000 round tests we discovered the accuracy improved. A few barrels were tested past 20,000 and accuracy never went below the original accuracy requirement."[8]

Maximum effective range is given as 800 meters (875 yd), but record shots have been made with the M24 at over 1,000 meters (1,094 yd). Meanwhile, the standard optical sight has a maximum elevation adjustment of 1,000 meters (1,094 yd).

[LR1955]

Found this (a portion only) on wikipedia about the M24 Sniper Weapon System.
My take on it is that Maximum Effective Range as a military standard is only about accuracy. So if you want a Grendel MEF, start with an accepted standard of accuracy and you will be able to calculate or test what it's MEF is.


They were rigorously tested before being approved by Remington and the military.
A U.S. Soldier training with a M24

Accuracy: According to MIL-R-71126(AR), 3.15.7 Targeting and Accuracy, The rifle shall achieve the dispersion set forth below when fired from a Government approved machine rest. The average mean radius shall be less than or equal to the values stated below. The minimum rate of fire for conducting this test shall be three rounds per minute.[3]

Range / Average Mean Radius (AMR) — Mean Radius (MR) expresses the average distance of all the shots from the center of the shot group. AMR averages the MR of several shot groups.

200 yards (183 m): 1.3 inches
273 yards (250 m): 1.4 inches
300 yards (274 m): 1.9 inches

The radial distance from the calculated center of impact of the first target compared to the calculated center of impacts of the subsequent targets shall be less or equal to 1.086 MOA (3.3 inches @ 300 yards, 2.2 inches @ 200 yards, 2.4 inches @ 200 meters) on an average basis.

The actual rifle requirements for accuracy were .35 MOA from a machine rest and according to Major John Mende (ret.) this accuracy had to be maintained to 10,000 rounds. He stated, "Interesting side note was there was a 10,000 round requirement for the barrel to maintain the original accuracy. In fact after some 10,000 round tests we discovered the accuracy improved. A few barrels were tested past 20,000 and accuracy never went below the original accuracy requirement."[8]

Maximum effective range is given as 800 meters (875 yd), but record shots have been made with the M24 at over 1,000 meters (1,094 yd). Meanwhile, the standard optical sight has a maximum elevation adjustment of 1,000 meters (1,094 yd).

Lemonaid:

Take if from a guy who has fired thousands of rounds of M-118 Special Ball out of M-24's. M-14 service and super match, the M-14 EBR, and a couple of Model 70 Match rifles.

I have never seen any of them hold one minute at 300 yards when firing issued M-118 Special Ball. I have seen them hold that when firing M-852 Match. The lots of M-118 LR that I used and witnessed being used were hit or miss in quality at the time they came out so can not comment on them.

As for 800 meters being the max effective range for the M-24 and an average trained Sniper team of the 1980's and 1990's using the 24, a 10X fixed mil dot reticle, M-118 Special Ball, at unknown distances to 1000 meters, I think a 50% chance of a first round hit on a E-Sil at around 800 meters is pretty damn good. The problem is, guys who do not shoot true unknown distance ranges, while laying in the prone, with a spotter in the prone using a M-49 scope, firing M-118, have no clue what so ever of the pure luck that goes into some of the longer shots with that particular equipment that is now obsolete.

I am sure what you cited is a requirement written sometime in the late 70's or early 80's when the 24 was being developed. Sounds right but never quite got there.

Not sure why you even cited this requirement. It reflects the technology of US Army sniping in the late 70's and into the 80's. It is obsolete today.

LR55

[Lemonaid]

Lemonaid:

Take if from a guy who has fired thousands of rounds of M-118 Special Ball out of M-24's. M-14 service and super match, the M-14 EBR, and a couple of Model 70 Match rifles.

I have never seen any of them hold one minute at 300 yards when firing issued M-118 Special Ball. I have seen them hold that when firing M-852 Match. The lots of M-118 LR that I used and witnessed being used were hit or miss in quality at the time they came out so can not comment on them.

As for 800 meters being the max effective range for the M-24 and an average trained Sniper team of the 1980's and 1990's using the 24, a 10X fixed mil dot reticle, M-118 Special Ball, at unknown distances to 1000 meters, I think a 50% chance of a first round hit on a E-Sil at around 800 meters is pretty damn good. The problem is, guys who do not shoot true unknown distance ranges, while laying in the prone, with a spotter in the prone using a M-49 scope, firing M-118, have no clue what so ever of the pure luck that goes into some of the longer shots with that particular equipment that is now obsolete.

I am sure what you cited is a requirement written sometime in the late 70's or early 80's when the 24 was being developed. Sounds right but never quite got there.

Not sure why you even cited this requirement. It reflects the technology of US Army sniping in the late 70's and into the 80's. It is obsolete today.

LR55

Only point from cited info was that MER was a results from an accuracy standard.
Your previous posts of a 50 percent hit rate being an example, MER has nothing to do (my reasoning) with the terminal effects when bullet meets target.
Allways appreciate your posts. Thanks!

[LRRPF52]

I've evolved with my thinking on Max Effective Range to be more of a factor of:

* Shooter experience shooting at distances where elevation and windage adjustments/holds are necessary
* Type of optic used relative to the user-friendliness for doing above
* Higher BC projectiles
* Lower recoil/ease of sight picture tracking during follow-through

The cartridge can be fudged around with the above parameters having more importance, as long as you still have penetration at distance.

I find that from alternate positions on any given day, including combat kneeling, hasty seated with quick adjust 2-point sling, I can hit 18" sils at 400yds repeatedly with a 14.5"-18" .224 Wylde SPR or Recce set-up with a good optic.

With 6.5 Grendel in the same carbine or rifle configurations with the exact same optics, that effective range pushes out a little more due to the superior wind drift, and you can actually see the effects on-target without having to guess whether you got a hit or not in the wind.

Transitioning into a more supported position for a DM or Sniper blocking/overwatch position, my effective range and hit probability go up significantly over the 77gr Mk.262 Match, but the 5.56 is easier to track the sight picture, although not significantly so.

Based on what I've seen over the years running many different open and closed courses with the DM or Sniper marksmanship training set, multiple active duty US Army and USMC Sniper Instructors who have spent a lot of time with the 6.5 Grendel all independently concluded that if we had 6.5 Grendel AR15s as the staple rifle for those types of courses, the results would be:

* Ease of learning to shoot long range would be superior to 7.62 NATO and the M118LR from SR25s/M110s (with 7.62 NATO, a new shooters is very reliant on spotter feedback)
* Positional shooting is a lot easier and results in higher hit counts,
* 1st-round hits are higher probability at distance,
* Shooter feedback is immediate since the sights don't come off TGT like with 175gr SMK M118LR
* The wind drift is better with the tighter twist rates of 6.5 bores and higher average BCs
* The lower working pressure provides longer barrel life and in-house armorers and instructors even can do rebuild work much easier
* You can gain more performance in the stress shoot stages since you're no longer lugging around a huge SR25 platform

The thing that is interesting to me is that these guys have approached me organically in chance meetings at different competitions and events, not knowing my background with 6.5 Grendel and then proceed to make my arguments to me without any prompt. It validates a lot of what I've been thinking over the years about the cartridge from the Sniper and DM perspective thinking that it would make an excellent addition to the arms room approach for units that have that flexibility and freedom.

For a standard rifleman cartridge, it would make sense in theaters like OEF and OIR where you have a lot of open spaces and distance, with a good intuitive combat optic to match the basic ballistic profile, but there are other weapons in a Platoon that also cover those distances well, and we're getting more and more ISR/Combat Drone support organic to dismounted units.

Back to the point of the thread though. Max effective range is highly dependent on shooter skill/experience matched with a good optic.

After that, we need to determine what we want the projectile to do once it connects.

[Lemonaid]

LRRPF52, that post is pure gold! Thanks!

[Lemonaid]

The accuracy standards you cite are for a bolt-action sniper rifle with 24" barrel, firing match grade ammo. It would seem reasonable to use those standards as a basis for a 6.5 Grendel sniper rifle, but they are totally inapplicable to determining the maximum effective range of a service grade 6.5 Grendel carbine with 16" barrel, firing service grade ball ammo.

You need to use the standards for 5.56 M855A1 Ball. The weight range of hypothetical EPR bullets has practical limits of around 95 gr at the low end, to about 125 gr at the high end. Considering the probable BC and MV of such loads, the max effective range seems likely to not differ greatly from that of 5.56 ball ammo.

[Sinclair]

Do you mean Max effective range or relative stopping power calculation?
M1 carbine max effective range 300 yards
M1 Garand max effective range 400 yards
M14 max effective range 500 yards
M16 max effective range 600 yards
At 600 yards the M1 has the highest relative stopping power.

This was about 55 years ago, with my MI Garand, I was told not to shoot at anything over 600 yards. The bullets went trans sonic just beyond that range causing them to yaw and hit probability was a little better than zero. I don't think that relative stopping power was a factor only hit probability.

P.S. I do not remember if it was a "C" or a "D" model, nor do I remember the ammunition designation, too many birthdays. I do remember my Father telling about the Officers would have them crank the rear sight up to max and fire enmass at some distant land mark to make the Germans take cover.