Army M24 Build Thread

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Not the best picture (been on the road a lot and haven't taken it outside, yet), but I finally got hands on the M24 I asked about a few pages back. It's in beautiful shape, RR prefix. I've got everything except a true Redfield rear sight base and correct L&S optic. I grabbed a rear sight base from Freelands in the meantime. Hopefully with this next work rotation I can grab one when they pop up on here.

I'm not 100% sure I'll end up keeping it. I need to finish getting my LO setup for USPSA as well as keeping money to get a business project off the ground.
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Anyone know where one can obtain the bigger lock ring for a M24 flash hider to use with barrels with the taller OK Weber front sight base? I managed to find a M24 flash hider, but it has the original lock ring for barrels with the shorter Remington/Redfield front sight bases. Thanks in advance.

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It took a while, but…

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Hello everyone,
I am trying to find out eye relief distance, real and apparent FOVs of Leupold M3A optics. Could anyone assist me with that?
Since there're so many specialists (it seems) on the early deployment SWS in this thread, it seems to be the best place to ask, but correct me if I'm wrong.
Many thanks,
J
 
 
You know the funny thing about those flash hiders is that when we got them no one knew what they were because they came through the supply channel long after the guns were issued. It took some time and then someone figured it out. I ran all of our sniper training and was running a course and doing a night fire when someone attached one and used it. I was very impressed at how well they worked and I still have one to this day.

Oh and I should add that they didn't work when we got newer rifles with the RPA sights because the front sight block is much taller than the Redfield. I told the Sniper PM from Picatinny about it years later after I had retired and was working for RAC and he was completely unaware.
 
Shooter 24 is done enough, grabbed a badger 1 piece mount. ASA receiver/bolt (bought from a friend), M24 trigger, sunnyhill bottom metal, correct follower, ect. Has a douglas barrel, and a modern scope, shoots well…I keep thinking of selling to fund an A1 build but just like the simplicity of it..

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Great! I snagged one from Euro resale and can't wait to have it delivered! I am a big fan of the slim shape and simplicity of the original M24! I can build a much more modern and better tactical bolt action or PRS tack driver if I want modularity, but THE M24 is irreplaceable.
 
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The history of M24 Sniper ammunition is documented in this article. Main focus is on the transition from M118 173gr. to the M852 168gr. The article is dated prior to 1980, and does not describe 175gr loadings.

NOTE:
In the study cited, evaluations of several commercial match grade bullets for their potential to improve the accuracy of the 7.62mm M118 Match Cartridge. It is inevitable that comparisons will be made between the performances of the various manufacturers as to the quality of their products. It should be stressed that the performance discussed in the cited study is directly applicable only to the M14 National Match rifle and therefore, these comparisons are
unwarranted. Individual shooters may find completely opposite results when hand loading their ammunition, and firing in other rifles. The relationship between ammunition and individual rifles is very sensitive, especially when striving to achieve the precision
required in competition.

The cited study did not attempt to prove which bullet design is superior to the others, but only the level of performance in one rifle system, the National Match M14. It is probably impossible to mass produce a Match cartridge that will satisfy all the competitors all the time.

EVOLUTION OF THE MATCH CARTRIDGE

A match cartridge, whose primary use is competitive Match type shooting and marksmanship training, is required to be the most accurate cartridge manufactured with production based equipment and processes. The accuracy of the M118 Match cartridge, introduced in 1964, had been criticized, almost from the outset, as being inferior when compared with the so-called "Mexican Match" cartridge. This "Mexican Match" cartridge is fabricated by simply removing the bullet from the M118 and replacing it with a commercial match grade bullet. The accuracy obtained with these "Mexican Match" cartridges has been reported to consistently outperform the M118 by a wide margin.

Several attempts were made in the early 1970's to improve the accuracy of the M118 by tightening component tolerances and process controls but these efforts met with little success. Rather than investing a relatively large amount of money in either bullet redesign, or the modernization of production equipment, improvement was accomplished without modification to other M118 cartridge components and with minimal production process changes.

Prior to World War II, ammunition for competitive Match shooting was primarily drawn from selected lots of caliber .30 service ammunition, or was made up on special order. When the National Matches were reinstated in 1953, it soon became apparent that service ammunition was not accurate enough for competitive shooting. Frankford Arsenal initiated a program in 1956 to develop a suitable Match cartridge. This program resulted in the M72, caliber .30 Match cartridge, capable of consistently delivering accuracy of 3.5-inch mean radius of 600 yards in the M1 National Match rifle. This ammunition/weapon combination performed admirably as the principal competitive system for several years.

With the introduction of the 7.62-mm, M14 National Match rifle and the M118 7.62-mm Match cartridge in 1964, the caliber .30 rifle and its ammunition have been gradually phased out of competitive matches. Although the velocity of the 7.62-mm cartridge is somewhat lower than its predecessor (2550 versus 2650 fps), the accuracy of these two cartridges is nearly identical, in large part due to the fact that they share the same bullet design.

Development of 7.62-mm match ammunition actually started in 1956 when the Office, Chief of Ordnance, directed Frankford Arsenal to manufacture 7.62-mm Ball ammunition of match quality for use in international matches on 300 meter ranges. The resulting design was designated the T275 International Match cartridge. Several changes were made to this cartridge which ultimately evolved into the M118, 7.62-mm Match cartridge in 1964.

THE T275 MATCH CARTRIDGE
The T275 cartridge and four later variations, designated T275El through T275E4, were assembled extra-long in order to assure that the bullet would rest against the forcing cone in the so-called "free rifles" of that period. A summary of the variations in these cartridges are listed below:

T275
Bullet - FA28871 174.5 grain, 9 degree boattail (.245" long)
Overall Cartridge Length - 2.860 -0.030"
Velocity - 2250 +/- 30 fps
Primer - FA No. 26

T275E1
Bullet - FA28871
Overall Cartridge Length - 2.960 -0.030"
Velocity - 2400 +/- 30 fps
Primer - FA No. 26

T275E2
Bullet - FA28871
Overall Cartridge Length - 2.960 -0.030"
Velocity - 2600 +/- 30 fps
Primer - FA No. 34

T275E3
Bullet - 8595434 174.5 grain, 9 degree boattail (.225" long) The same bullet as the M72
Overall Cartridge Length - 2.860 -0.030"
Velocity - 2640 +/- 30 fps
Primer - Remington #72

T275E4
Bullet - 8595434
Overall Cartridge Length - 2.860 -0.030"
Velocity - 2275 +/- 25 fps
Primer - FA No. 36
 
During 1958, funds were provided to production engineer the T275E4 design and prepare a technical data package for mass production. It was during this effort that definitive weights and tolerances for the bullet and its components were determined, and a two-draw bullet jacket process evolved. This process improved jacket wall thickness variations and significantly improved bullet accuracy.

M118 MATCH CARTRIDGE
In 1961, Frankford Arsenal received an order for 50,000 Match cartridges from Springfield Armory, to be used for testing the M14 National Match rifle. The T275E4 cartridge was at that time redesignated the XM118. These cartridges were loaded with Hercules HPC 6 propellant at a nominal velocity of 2550 fps, and the overall length was reduced to 2.83-.03 inches to facilitate feeding in the M14 magazine.

Mouth Waterproofing
During this period, testing was conducted to determine if mouth waterproofing had any effect on the ballistic characteristics of the cartridge. Much to the chagrin of competitive shooters, these tests indicated that mouth waterproofing did not effect bullet accuracy, but would improve storage stability. Because the M118 cartridge was intended for use in combat by snipers, in addition to its primary competitive match function, storage for long periods was considered an essential requirement. The cartridge drawing was, therefore, changed to reflect the addition of mouth waterproofing in November 1961.

Determination of Velocity-Accuracy Relationship
Up to this time, no scientific study had ever been conducted to establish an optimum velocity-accuracy relationship for 7.62-mm Match ammunition, as was evidenced by the changing velocity specifications of the T275 cartridge series. The various velocities for each cartridge type were determined and prescribed by the Infantry Board at Fort Benning, Georgia. A comprehensive test to determine the relationship between velocity and accuracy at various ranges was initiated by Frankford Arsenal in 1961 and completed in early 1962. These tests were conducted at ranges of 200 to 1000 yards using velocities of 2300, 2400, 2500, 2600, 2640, and 2700 fps. At the conclusion of these tests, it was determined that for ranges up to 600 yards, the best accuracy was achieved with a velocity between 2500 and 2600 fps. On 23 August 1962, an Engineering Change Request was issued that changed the velocity specification from 2640 ± 30 fps to the present specification of 2550 ± 30 fps.

Primer and Propellant Evaluations
Although the T275 cartridge series used IMR 4895 propellant, the emphasis on increased velocities and the attendant increase in chamber pressures, necessitated the search for a propellant compatible with the No. 26 Primer and capable of achieving up to 2700 fps. Several propellants were tested, and a Hercules propellant, designated HPC #6, was selected for use in the first 50,000 rounds of XM118 to be shipped to Springfield Armory. However, high pressures, experienced with this propellant at cold temperatures, led to the reduction of the velocity specification to 2640 fps. This change allowed the use of additional propellants and eventually WC846 was selected as the prime propellant in lieu of the HPC #6.

Shortly thereafter, the velocity-accuracy tests mentioned previously were completed, which now established 2600 fps as the top velocity requirement and recommended use of the #34 Primer. A new series of propellant tests were then conducted which ultimately determined that both WC846 and IMR 4895 were compatible with the #34 Primer, and were subsequently recommended for use in the XM118 cartridge. A summary of M118 Match cartridge performance requirements as specified in MIL-C-46934 is listed below:

Velocity @ 78 feet - 2550 ± 30 fps
Accuracy @ 600 yds - 3.5 Mean radius max
Chamber Pressure @70 degrees - <50,000 psi (radial copper)
Port Pressure @ 70 degrees - 12,500 ± 2000 psi
 
User Dissatisfaction with the M118 Cartridge

For several years after its introduction, the M118 cartridge performed satisfactorily, and was well received, although complaints were registered regarding excessive barrel fouling associated with ammunition lots having WC846 ball propellant. A series of tests conducted at Frankford Arsenal concluded that, although the WC846 did foul the bore somewhat, the fouling was no worse than when IMR 4895 was used, and the effect of the fouling on accuracy was too small to be observed. However, they noted that WC846 residue was much harder to remove from the bore than IMR 4895 residue.

Another user complaint regarding propellant was the higher bulk density of WC846 (0.980 g/cm versus 0.900 g/cm for IMR 4895). WC846 generally meets the required velocity/pressure levels at a charge weight that allows a small air space inside the cartridge. Whereas, IMR 4895, having a lower bulk density, will normally be loaded to 100% case capacity. Residual air space within the case has always been regarded as undesirable, due to its contribution to variations in velocity and pressure, causing an accuracy variation. As a result of these problems associated with WC846 propellant, all M118 Match cartridge production since 1970 has been loaded with IMR 4895 propellant.

By the early 1970's, the accuracy performance of the M118 cartridge was being severely criticized as inferior, when compared to hand loaded cartridges using commercial Match grade bullets. In fact, several Marksmanship Training Units had initiated a procedure whereby they extracted the bullet from the M118 cartridge and replaced it with a 168 grain Sierra, cal. .30, International Match bullet, and referred to it as the "Mexican Match" cartridge. The ammunition loaded in this manner reportedly achieved an accuracy which was 25% to 50% better than standard M118 cartridges.

Several early attempts were made by Frankford Arsenal, circa 1972-1975, to initiate Product Improvements to the M118 by investigating the adequacy of commercial match bullets, by tightening the M118 Cartridge tolerances, and modernizing production equipment. However, these efforts never evolved into actual approved programs. Finally in 1976, ARRCOM instructed ARRADCOM to implement a "product-definition" to the Technical Data Package (TDP) of the M118 Match cartridge. This effort was to improve the M118 accuracy and made the following changes to the technical requirements:

Velocity
The average velocity, at 78 ft from the muzzle, of the sample cartridges conditioned at 70°F ± 2°F shall be 2550 ± 20 fps. The standard deviation of the velocities shall not exceed 18 fps.

Accuracy
The mean radius of any target of the sample cartridges shall not exceed 2.5 inches at a target distance of 600 yards.

Air Space
The cartridges shall be loaded such that the average and standard deviations of the velocities of various samples of cartridges, each sample handled when fired so as to vary the propellant position from sample to sample, shall not be statistically different.

Bullet Weight
The bullet weight within any lot shall be limited to a tolerance of 0.8 grains.

In addition to the above changes to the M118 specifications, several tolerance changes were incorporated into the drawings of the bullet and cartridge case to reduce concentricity and wall thickness variations. The Lake City Army Ammunition Plant (LCAAP) agreed to produce the M118 cartridge to the revised TDP on a "best effort" basis, since they could not guarantee that compliance with the above mentioned changes would produce a more accurate cartridge. The M118 Match cartridge was produced to those specifications starting in February 1977, the first lot being LC-60.

On 17 August 1978, a briefing was conducted at ARRCOM for Undersecretary of the Army, Dr. Walter LaBerge, to review the status of the M118 Match cartridge. By comparing the past performance against the latest production efforts, it was apparent that the changes made to the TDP had not achieved the desired effect. The ten year production average prior to the change in the TDP was a 2.47-inch mean radius. After producing 12 lots to the revised TDP, this average remained essentially unchanged at 2.41 inches, see below:

LC-60-1 600 yd mean radius - 3.0
LC-60-2 600 yd mean radius - 2.6
LC-60-3 600 yd mean radius - 2.3
LC-60-4 600 yd mean radius - 2.4
LC-60-5 600 yd mean radius - 2.5
LC-60-6 600 yd mean radius - 2.6
LC-60-7 600 yd mean radius - 2.4
LC-60-8 600 yd mean radius - 2.2
LC-60-9 600 yd mean radius - 2.4
LC-60-10 600 yd mean radius - 2.3
LC-60-11 600 yd mean radius - 2.1
LC-60-12 600 yd mean radius - 2.1

12 lot average mean radius - 2.41

It appeared then that a 2.4 to 2.5 inch mean radius represented a practicable limit for the average lot of M118 Cartridge when manufactured by the process employed at LCAAP. Two apparent alternatives remained to improve the M118 cartridge accuracy; completely modernize the production equipment at an initial investment cost of approximately one million dollars or, investigate the practicality of purchasing commercial "Match Grade" bullets and providing them to the load plant as Government Furnished Materiel (GFM). The decision reached at the 17 August 1978 meeting was to pursue the latter alternative. The final action taken at this meeting was to draft a tentative requirements document, which Headquarters, U.S. Army Forces Command (FORSCOM) formalized in a letter to ARRCOM on 14 December 1978. On 22 January 1979, ARRCOM responded to this requirement by requesting that ARRADCOM prepare a Product Improvement Program (PIP), to be initiated in FY81. This was later changed to an Engineering Study Program (ESP) approved in September, and initiated in December, 1979. The activities detailed in the following sections are the result of that program.
 
EVALUATION OF COMMERCIAL CALIBER .30 MATCH GRADE BULLETS

This engineering study was undertaken to improve the accuracy of the M118 Match cartridge, as authorized by U.S. Army Forces Command (FORSCOM) letter requirement, dated 14 December 1978. Specifically, the requirement states that the accuracy of any five, 14 shot targets at 600 yards shall not exceed a 6-inch extreme spread. Other requirements of the M118 Match cartridge were to be retained. In addition, bullets having an open nose were authorized. Since earlier attempts to improve the accuracy of the M118 cartridge through process and tolerance controls had been largely unsuccessful, this program was directed towards the evaluation of commercial match-grade bullets as a potential replacement for the current bullet used in the M118 cartridge.

Technical Approach
A survey of commercial sources for off-the-shelf caliber .30 Match bullets in the 168 to 170 grain weight range indicated that three American and one foreign corporation market this type of bullet, and another was developing such a bullet that was not yet available, see below:

Commercial Match-grade bullets

Sierra Bullets #2200
Hornady Mfg Co. #3050
Nosler Bullet Co. #28473
Lapua (Finland) #D46 (170 gr)
Omark Industries (SPEER) #2040 (not available for testing)


All bullet designs except the Lapua are manufactured in the United States by a soft swaged, nose closing process, more commonly referred to as "hollow point". The Lapua bullet, manufactured in Finland, is the only bullet evaluated which has a conventional hard nose, like the M118 bullet. Other than manufacturing tolerances, the main difference in the Lapua bullet is it's rebated boattail, common to many European bullet designs.

All bullets evaluated in this study could be freely substituted for the standard M118 bullet with only a minor propellant charge adjustment to achieve the desired velocity. All of the other cartridge components used in this study were standard M118 components.

Because the prime consideration was to improve accuracy, the bulk of the testing was geared towards evaluation of the accuracy of the bullet candidates at various ranges. In addition, other testing was conducted to insure complete compatibility with the M14 rifle.

Tests and evaluation factors
1. Accuracy at ranges up to 600 yards
2. Velocity and pressure uniformity
3. Radar evaluation of velocity decay
4. Trajectory mismatch
5. Cost comparison
6. Dimensional and weight uniformity

In order to evaluate the performance under normal production conditions, 11,040 rounds (12 wirebound crates) of each bullet type were loaded on regular production loading machines at the Lake City Army Ammunition Plant. The only process change made was the substitution of a contoured-bullet insertion tool to prevent damage to the bullet points, and a cartridge case identity knurl for identification. The balance of the assembly process was unchanged from normal production of Match ammunition. To insure compatibility of test data, an M118 cartridge lot, LC 79K-130-007 was earmarked as a control lot and shipped with the test cartridges to the testing facilities listed below:

U.S. Army Research & Development Command
U.S. Army Marksmanship Training Unit, Ft Benning
U.S. Marine Corps Marksmanship Training Unit, Quantico
U.S. National Guard Marksmanship Training Unit, Nashville

Test Program

Accuracy Testing
As originally structured, all of the Marksmanship Training Units were scheduled to shoot identical accuracy test programs at 200, 600, and 1000 yards. This was later modified slightly to accommodate the varying range facilities at each agency. The 1000-yard requirement was eliminated from the MTU tests due to difficulties encountered in the testing of the first Sierra bullet lot LC80C-300-S-090 prior to the 1980 National Matches, and because the MTU's felt that 1000-yard tests were unwarranted. However, testing at 1000 yards were conducted at ARRADCOM's Ft. Dix Test Site to gather information on dispersion at that range.

Although the diversified accuracy testing by the test agencies gives a broad evaluation of the potential of the candidate bullets under varying conditions, it does not indicate how well these bullets can perform when the selection of barrels is considered. The discrete test, which allows the best barrels to be used, is a much better indicator of the lowest dispersion potential for these bullets, and is a more realistic means of comparing performance in competitive matches, where the shooters will be using finely tuned weapons.

Testing at ARRADCOM and Lake City Army Ammunition Plant was conducted using 7.62-mm accuracy barrels from a fixed mount, while the MTU's conducted their testing in National Match M14 rifles. Analysis of the accuracy data from the test agencies was complicated somewhat by inconsistencies. The Marine Corp MTU data, for example, was based on Figure-of-Merit measurements rather than extreme spread, and the 300-yard accuracy tests were conducted using 5-round targets.

In general, the Sierra bullet displayed the greatest accuracy performance with a range averaged improvement 32% better than the M118 cartridge. The Lapua bullet also showed a significant improvement at 23% better than the M118. Of the other two bullets evaluated, the Nosler ranked third with a 15% improvement and the Hornady bullet fourth with performance slightly worse than the M118. The Marksmanship Training Units unanimously recommended the adoption of the Sierra bullet.

Velocity and Pressure Uniformity
Velocity and pressure measurements indicated that all of the bullet candidates are very consistent, with only slight variations between bullet types. The tight tolerances associated with these bullets is a major contributor to this uniformity. The small variations in velocity and pressure between bullet types are considered to be a function of propellant loading and/or other system variables.
 
DIMENSIONAL AND WEIGHT INSPECTION
One hundred bullets of each type were randomly selected and weighed on a Metzler PC 180 electronic scale. Additionally, twenty bullets of each type were measured on a comparator uniformity of outside diameter, overall length, and boattail length. The results of this survey are summarized below:

Bullet weight inspection (all weight in grains)
Bullet Type//Avg Wt//Ext Spread//High Wt//Low Wt
Sierra//168.0//0.60//168.3//167.7
Hornady//167.7//0. 60//168.1//167.5
Nosler//168.0//0.80//168.5//167.7
Lapua//169.8//0.78//170.3//169.5

Bullet dimensional check (all dimensions in inches)
Bullet Type//Overall Length//Diameter//Length of Boattail
Sierra//1.242 max-1.234 min//0.3084 max-0.3081 min//0.170 max-0.160 min
Hornady//1.239 -1.230//0.3086 -0.2080//0.200-0.190
Nosier//1.211-1.200//0.3084-0.3079//0.110-0.100
Lapua//1.255 -1.250//0.3092-0.3086//0.250-0.236

Downrange Velocity Decay
The four commercial bullets and the standard M118 cartridge were tested for velocity retention and coefficient of drag using a Hawk doppler radar to track the projectiles. As would be expected, the M118 bullet being slightly heavier, retains its velocity slightly longer than the others. The Sierra, Hornady, and Lapua bullets track very closely together. The Nosler bullet loses velocity rapidly, which accounts for the poor long range accuracy experienced with this bullet.

Accuracy Mismatch
A series of tests were conducted with each bullet to determine if there was any noticeable trajectory mismatch or other functional problems associated with the commercial bullets relating to the M14 rifle and sight system. No problems were encountered with any of the candidate bullets. As might be expected, when changing from the M118 to any of the other lighter bullets, a minimal sight correction is required.

Aerodynamic Analysis of Match Projectiles
A limited aerodynamic analysis was undertaken to predict why the commercial match bullets are more accurate than the conventional M118 bullet. This analysis consisted of determining the sensitivity of various bullet dimensions on accuracy. The conclusion of this analysis was that the effect of the studied external geometry variations on dispersion is much less than acceptable lot variations, and these variations act only in the vertical plan. Other sources of dispersion that act in both horizontal and vertical planes are: the offset of the center of mass of the projectile from the center of form, rifle barrel vibrations, non-symmetrical reverse flow over the projectile at muzzle exit, core imperfections and improper seating, and yawing during the first few feet after exit. Any difference in dispersion between the standard M118 bullet and the commercial Match bullets tested can only be attributed to the manufacturing processes that allow better control of both internal and external dimensional variations.

Comparison of Bullet Costs
Cost estimates for the two most accurate bullets, the Sierra and Lapua, were obtained from the bullet suppliers, and compared with the latest available M118 bullet manufacturing cost. Costs of the two commercial bullets are predicated on quantities of 5 million or more delivered freight pre-paid to the Lake City AAP. Unit costs for smaller quantities would obviously be higher. It should be pointed out that the cost of the Lapua bullet, because it is imported from Finland, will vary due to fluctuations in currency exchange rates.

M118 - (actual 1980 cost = 6.7c) Projected 1981 Cost (c) - 7.4
Sierra - Projected 1981 Cost (c) - 7.1
Lapua - Projected 1981 Cost (c) - 8.6

LEGALITY OF OPEN-NOSED MATCH BULLETS
The superior accuracy potential of commercial Match bullets had been recognized for several years. However, their exploitation in a quasi-military Match cartridge had been eschewed, owing to the fact that American manufactured Match bullets are fabricated by a soft swaged process resulting in an open nose. This type of bullet, if it was intended for use in combat, could be viewed as a violation of the Geneva Conventions, which proscribe so-called "dum-dum" bullets. This prohibition, contained in the 1899 Hague Declaration IV, "Concerning Expanding Bullets," bans those bullets "which expand or flatten easily in the human body." Although not a party to this declaration, the United States has acknowledged that it will abide by the terms of these agreements.

Regarding open-nosed ammunition, intended to be used only for marksmanship and competitive shooting, the Office of the Judge Advocate General has issued a preliminary opinion, stating that this type of ammunition does not need to be evaluated against the International Conventions. This opinion is based fundamentally on the stated use of the cartridges for non-combat purposes with special markings to avoid inadvertent introduction into a combat zone, and proper security in storage and transit. [NOTE- at the time of this articles publication in July 1981]

In the implementation of the special marking requirement, warnings have been applied to all exterior and interior packaging, and positive identification of individual rounds has been insured by the placement of a knurl on the cartridge case body. The identity knurl used on the 1980 National Match lot of ammunition was an interim design that proved difficult to apply and a few instances of case separation were experienced. The knurl on this design was only 0.025 in. wide and was located 0.500 in. from the head. An improved identity knurl was later developed that is located closer to the case head and widened to 0.060 in. This design is much easier to apply to the case, is much more visible than the initial design, and because it has been moved slightly rearward, where the case wall is stronger, no further functional problems are expected. Figure 15 depicts both the initial and final design of the identity knurl.

The Lapua bullet is the only design tested that has a hard nose similar to the standard M118 bullet, and it is one of the two bullets that gives a significant increase in accuracy. Because it has a hard nose rather than hollow point, it could be directly substituted in the M118 cartridge and used in sniper applications.

To determine what advantage, if any, the Lapua would have in the sniper role, a series of hit probabilities were calculated which compared it to the M118 standard bullet. The hit probabilities were based on zero error and 0.5 mil aiming error, and considered against standing, prone and kneeling man-sized targets. With zero aiming error the hit probability is 1.0 for all targets out to 600 yards and then the Lapua bullet, because of increased dispersion at longer ranges, drops off much faster than the M118 bullet. For instances with 0.5 mil aiming error, which is probably the largest expected of snipers, the aiming error partially masks the better dispersion of the Lapua bullet with the net result that the Lapua bullet does not offer any real advantage in the sniper role. When the added cost of the Lapua bullet is considered, there is no longer any reason for advocating its use in the sniper role. For competitive shooting up to 600 yards, however, use of the Lapua bullet is second only to the Sierra bullet.
 
1980 NATIONAL MATCH CARTRIDGE

Work on the basic engineering study to evaluate commercial match-grade bullets had just been initiated when, in January 1980, the U.S. Army Armament Materiel Readiness Command (ARRCOM) notified ARRADCOM that they had received a request from the Director of Civilian Marksmanship (DCM) for an improved accuracy 7.62-mm Match cartridge for the 1980 National Matches. Specifically, the requirement was for a quantity of 200,000 rounds to be delivered to Camp Perry, Ohio, by 17 July 1980. ARRADCOM responded by redirecting the Engineering Study into a priority effort to meet the July 1980 deadline. A coordination meeting was held at Lake City Army Ammunition Plant (LCAAP) between representatives of ARRCOM, ARRADCOM and LCAAP contractor personnel to discuss this effort on 7 February 1980, determine priorities and work up a schedule to meet the July delivery. This effort was undertaken on a best effort basis with no guarantee that an improved accuracy cartridge could be tested and approved within the available time given the five month schedule.

It was determined at the 7 February meeting that an initial evaluation quantity of 13,800 rounds would be fabricated and tested by ARRADCOM and three Marksmanship Training Units (MTU) prior to a final decision on production of the 200,000 quantity. Arrangements were made with the U.S. Army, Marine and National Guard MTU's to test a portion of the initial test lot, in order to get a broad based evaluation in a short period. As for the choice of which bullet to use, the Sierra 168 grain International Match bullet was considered to entail the lowest risk since the MTU's had been using this bullet for some time.

If the initial test lot performed as expected, the Sierra bulleted cartridge would then be type classified as Limited Procurement (LP) to allow the production of the larger 200,000 round lot for the 1980 National Matches. Meanwhile, ARRADCOM would hand load and test a small quantity to provide data for the release of an Interim Safety Statement, prepare the necessary drawings, and obtain the nomenclature assignment.

Sierra bullets, more commonly referred to as hollow points, are made by a soft swaged nose process as are all American made commercial Match bullets. Because these hollow pointed bullets, loaded at a United States loading facility, might be construed as a violation of the Geneva conventions, special markings on all exterior packaging and on identity knurl on the cartridge case were considered essential. Special care was taken with the handling and marking to prevent inadvertent use of these cartridges in a potential combat situation. Subsequently, a legal opinion was received from the Office of the Judge Advocate General, which stated that the use of Sierra bullets, these bullets as intended could not be construed as violation of any International Convention.

By the middle of February, drawings had been prepared and an interim 7.62-mm cartridge, designated Special Match, PXR-6308 had been assigned. The load plant completed the first lot of 13,800 rounds, LC80C-300-S-090 on schedule, and testing by ARRADCOM and the MTU's proceeded without delay. A standard M118 cartridge Lot LC79K130-007 was earmarked as a control lot and used by all test agencies to compare the accuracy of the test lot. Results of these tests are summarized below:

Ballistic acceptance data for Lot# LC80C 300-S-090

Propellant Charge - 43.0 grains IMR 4895
Velocity @ 78 feet - 2535 fps
Chamber Pressure - 44,100 psi
Port Pressure - 12,300 psi
Accuracy @ 600 yds - Mean Radius: 2.2 inches/extreme spread: 8.8 inches

Results from comparison testing (extreme spread):

LCAAP (Mann Barrel/Machine rest)
- M118: 9.6 (@ 600 yds)
- PXR-6308: 8.8

ARDEC (Mann Barrel/Machine rest)
- M118: 2.3 @200yds/3.9 @300/9.9 @600
- PXR-6308: 1.8 @200yds/3.3 @300/7.3 @600

FT Benning AMU (M14/Machine rest)
- M118: 7.3 @300/13.9 @600/27.3 @1000
- PXR-6308: 4.7 @300/9.5 @600/25.0 @1000

US National Guard AMU (M14/Machine rest)
- M118: 4.5 @200/15.7 @600
- PXR-6308: 3.3 @200/11.9 @600

USMC MTU (M14/Shoulder)
- M118: 6.9 @300/12.8 @600
- PXR-6308: 5.0 @300/10.3 @600


Comments of the MTU's on the performance of the Sierra bulleted cartridges were very favorable due to the obvious improvement in accuracy over the standard M118 Match cartridge. The actual improvement in accuracy averaged at least 25% better than the M118 cartridge for all ranges out to 600 yards.

On 7 May 1980, the Special Match cartridge, PXR-6308 was type classified as limited procurement, and fabrication of the 200,000 round 1980 National Match lot was initiated. This lot, designated Lot LC-80F-300-S111 was delivered to Camp Perry on 10 July 1980, one week ahead of schedule.

The above article is mostly derived from ARSCD-TR-81018 "7.62mm Match Cartridge Accuracy Improvement Program" by J. W. Hettel
 
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Started reloading using the new Sierra 169gr SMK with a .527 BC that provides super sonic performance out past 1,000 yards. Using a compressed load of Varget in M852 Lake City 1989 MATCH cases (2635 fps), my EuroOptic M24 Limited Edition Army Sniper School achieves 0.85964" Average Mean Radius for 25 shots at 300 yards. Army spec for acceptance of the M24 was 1.90" AMR at 300 Yards fired from an Aberdeen Arsenal Mann machine shooting rest with the M118 173gr round.
 
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Franklin Ware Mann at Aberdeen Proving Grounds using his Mann Accuracy shooting machine rest. He was best friends with Harry Melville Pope, of Pope Barrels & Gunsmithing. He used Pope barrels exclusively in his shooting rests. These barrels are sold occasionaly on the CMP Auction website, and are prized collector items.
 
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Very interesting but seems to contain some revisionist history. I still have cans and boxes in the garage marked "M852 7.62mm Match. NOT FOR COMBAT USE," as shown in the last two photos (bottom right) above.

COL Hayes Parks' determination (as the DOD Staff Judge Advocate) that M852 (and Match King-type open-tip munitions) do NOT violate the Hague Conventions wasn't written until the late 1990s.
 
It wasn't the USAMU's failure to request approval for combat use (remember, the USAMU established the sniper mobile training teams that instructed in Vietnam, then post-war through 1987 when Fort Benning established the infantry's sniper school).

The Army's Tank Automotive and Armament Command solely (slowly) determines whether or not a weapon or ammunition item is designated and adopted as Army standard and safety approved -- one of the reasons USSOCOM uses the Navy's Surface Warfare Center at Crane for small arms and ammunition development, testing, and safety certification.

USSOCOM didn't exist in 1980-87 so all ammo development would have had to have gone (slowly) through Army.

Note Random Guy's slide above -- Mark 248, MK 262, MK316, and MK248 MOD 1 are Naval ammunition designations for ammo developed for SOCOM. I don't know if Barrett MK22 sniper ammo is "M" or "MK" designated.
 
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The shorty SR-25K is a good possibility. I just never saw any documentation or drop charts for it prior to Radom Guys post. Still got half a box of them sitting from like 30+ years ago. Used to reload for my SIG PE-57 (semi StGw57) in 7.5 Swiss because it duplicated the Schweizer Armee standard round.
 
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On 7 May 1980, the Special Match cartridge, PXR-6308 was type classified as limited procurement, and fabrication of the 200,000 round 1980 National Match lot was initiated. This lot, designated Lot LC-80F-300-S111 was delivered to Camp Perry on 10 July 1980, one week ahead of schedule.
…I was able to acquire one of the original boxes from that first batch of M852 back in 1980:
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I wasn't competing back when dinosaurs roamed 😉

But by the time I did start, every range officer of whichever club I was shooting at usually offered to trade for my issued .30-06 Match allotted (64 rounds?) ammo, for some variation of 7.62 surplus scrounged cartridges they had dragged along for trade bait. It was a DCM requirement back then to include 30-06 ammo if that club owned gov't supplied M1 Garands to be used for service rifle competitors, irregardless of the rifle we actually used. Never was offered anything close to your M852 experimental. Usually it was corrosive berdan South African 7.62.