ad-e403 047__development of a lightweight ammunition concept [2005]

8/12/2019 AD-E403 047__Development of a Lightweight Ammunition Concept [2005]

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ADAD-E403 047

Technical Report ARAEW-TR-05006

DEVELOPMENT OF A LIGHTWEIGHT AMMUNITION CONCEPT USINGAN ALTERNATIVE CASE MATERIAL AND ENHANCED PROPELLANT

Todd CloutierVeritay Technology, Inc.4835 Millersport HwyEast Amherst, NY 14051-0305

Lucian SadowskiProject EngineerARDEC

May 2005

ARMAMENT RESEARCH, DEVELOPMENT ANDENGINEERING CENTER

Armaments Engineering and Technology Center (Benet)Picatinny, New Jersey

Approved for public release; distribution is unlimited.


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The views, opinions, and/or findings contained in thisreport are those of the author(s) and should not beconstrued as an official Department of the Army posi-tion, policy, or decision, unless so designated by otherdocumentation.The citation in this report of the names of commercialfirms or commercially available products or services doesnot constitute official endorsement by or approval ofthe U.S. Government.Destroy this report when no longer needed by any methodthat will prevent disclosure of its contents or reconstructionof the document. Do not return to the originator.


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REPORT DOCUMENTATION PAGE Form pprovedOMB No 0704-01-0188The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sourcegathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of thcollection of information, including suggestions for reducing the burden to Department of Defense, Washington Headquarters Services Directorate for Information Operations and Repor(0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shallsubject to any penalty for failing to comply with a collection of information if it does not display a currentiy valid OMB control number.PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS.

1 REPORT DATE (DD-MM-YYYY) 2. REPORT TYPE 3. DATES COVERED From TO)May 2005 Final July 2003 to November 20044. TITLE AND SUBTITLE 5a. CONTRACT NUMBERDEVELOPMENT OF A LIGHTWEIGHT AMMUNITION CONCEPT DAAE30-03-C-1 132USING AN ALTERNTIVE CASE MATEIAL AND ENHANCED 5b. GRANT NUMBERPROPELLANT 5c. PROGRAM ELEMENT NUMBER6. AUTHORS 5d. PROJECT NUMBERTodd Cloutier, Veritay Technology, Inc. 5e. TASK NUMBERLucian Sadowski, Project Engineer, ARDEC 5f. WORK UNIT NUMBER7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATIONUSA ARDEC, AETC (Benet) REPORT NUMBERVeritay Technology, Inc. Weapons Systems and Technology4835 Millersport Hwy. (AMSRD-AAR-AEW-M)East Amherst, NY 14051 Picatinny, NJ 07806-50009. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR'S ACRONYM(S)USA ARDEC, EMTechnical Research Center (AMSRD-AAR-EMK) 11. SPONSOR/MONITOR'S REPORTPicatinny, NJ 07806-5000 NUMBER(S)Technical Report ARAEW-TR-0500612. DISTRIBUTION/AVAILABILITY STATEMENTApproved for public release; distribution is unlimited.13. SUPPLEMENTARY NOTES

14. ABSTRACTSoldiers are carrying additional high technology equipment to increase effectiveness at additional weight. Toachieve a significant weight reduction and to enhance soldier's effectiveness, the Joint Service Small ArmsProgram Office is developing a Lightweight Family of Weapons and Ammunition. The ammunition conceptdeveloped during this contract combines a lightweight cartridge case and a high-density consolidatedpropellant charge that substantially reduces the cartridge volume. This report describes the lightweightcartridge case development from conception , thermally consolidated propellant fabrication and testing.

15. SUBJECT TERMSAmmunition Small Arms Cased telescope16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF 18. NUMBER 19a. NAME OF RESPONSIBE PERSONABSTRACT OF Lucian Sadowskia. REPORT b. ABSTRACT c. THIS PAGE PAGES 19b. TELEPHONE NUMBER (Include areaU U U SAR 14 code) (973) 724-2555Standard Form 298 (Rev. 8/98Prescribed by ANSI Std. Z39.1


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CONTENTSPage

Introduction 1Overview 1Objective 1

Lightweight Ammunition 2Thermally Consolidated Propellant 2Lightweight Ammunition Ballistic Evaluation 5Lightweight Cartridge Case 7Ammunition Weight Distribution 8

Conclusions 10Distribution List 11

FIGURES1 Propellant consolidation mold 42 Consolidated propellant charge 43 Single-shot ballistic test fixture 54 High speed photograph of bullet in flight 65 Chamber pressure-time cures for the lightweight ammunition 76 Weight distribution of the Veritay lightweight ammunition concept 97 Weight distribution of the conventional M80 ball ammunition for M240B 9medium machine gun


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INTRODUCTIONOverview

The Army's proposed concept for the Objective Force Warrior (OFW) will enhancewarfighter lethality and survivability. The OFW will have full spectrum capabilities , meaningthat troops can use it for any mission from peacekeeping to high-intensity conflicts. Plansinclude the addition of many new capabilities to provide that level of flexibility. These newadvances in weapon systems result in soldiers carrying additional high tech equipment toenhance effectiveness, but at the cost of increased weight. It is important that the warfighterbecome more effective and make use of the added capability provided by the OFW initiative,and not merely discard these tools when the fighting becomes more intense or mobile.Consequently, it is desirable for the OFW system to be implemented with an actual reduction inweight. This requires a significant weight reduction for weapons and ammunition withoutsacrificing warfighter effectiveness or safety.

To achieve a significant weight reduction and enhance soldier effectiveness, the JointService Small Arms Program Office (JSSAP), Armament Research, Development andEngineering Center (ARDEC), Picatinny, New Jersey is developing a Lightweight Family ofWeapons and Ammunition (LFWA). As part of this initiative, advanced gun and ammunitionsystem design technologies are being investigated to develop smaller and lighter componentsand end items without sacrificing performance and safety. The objective of the subject contractis to develop lightweight small caliber ammunition with concomitant weight and volume benefitsfor the entire weapon system.

The ammunition concept developed during this project combines a lightweight cartridgecase and a high-density consolidated propellant charge that substantially reduces the cartridgeweight and volume. Reducing the size and weight of the ammunition cartridge createsopportunities for synergistic weight reduction in weapon design and in ammunition packagingmaterials. Furthermore, reducing the volume and weight of the ammunition reduces the burdenon the logistics train and enables the warfighter to carry additional rounds of ammunition orother equipment that will enhance combat effectiveness.

Replacement of heavy ammunition cartridge cases made of brass or steel with casesmade of advanced lightweight materials will considerably reduce the weight burden associatedwith the ammunition. By incorporating other advanced ammunition design elements, ammuni-tion weight can be further reduced.Objective

The objective of this program was to develop and demonstrate a lightweight ammunitionconcept, in 7.62-mm caliber, which maximizes potential weight savings without compromisingfunctionality of the ammunition. Previous lightweight ammunition development programs haveinvestigated aluminum or polymer cartridge case replace-ments, or elimination of the cartridgecase altogether, with varying degrees of success.

Since the intent of this BAA was to take a clean sheet approach to lightweightammunition and weapon design, an ammunition concept was developed that provides most ofthe weight reduction benefits of caseless ammunition, but at reduced risk. Three areas of

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potential improvement over the existing conventionally cased ammunition (e.g., M80, M855)were identified: ammunition weight, ammunition size, and ballistic performance. Reduction ofthe ammunition weight was the primary goal, with a target of at least 30%, which was accomp-lished mainly through use of a lightweight cartridge case. Reducing the ammunition size orvolume as much as deemed feasible was also an important design goal, which was accomp-lished using thermally consolidated propellant. While increased performance could also beachieved, there was no requirement for this. As a result, the program objective was to meet theperformance and safety characteristics of current conventional ammunition, while achieving theweight reduction cited. These objectives allow the weight and volume reduction efforts of thesubject program to be evaluated with respect to currently fielded conventional ammuni-tion withthe same performance.

LIGHTWEIGHT AMMUNITIONSmall caliber ammunition must perform dependably and consistently in a wide range ofenvironmental conditions, survive handling during transport and loading, and maintain function-ality over a 20-yr storage life. The lightweight ammunition concept developed during this project

incorporates a thermally consolidated propellant that reduces the volume occupied by thepropellant, and thus reduces the size of the ammunition, and a lightweight cartridge case thatreduces the weight of the ammunition and provides protection from rough handling and theenvironment. The caliber selected for this development effort was 7.62 mm and the ballisticperformance target was the M80 ball ammunition.Thermally Consolidated Propellant

The normal loading density for a loose granular propellant charge is between 0.9 and 1.0gm/cm 3. To increase the chemical propulsive energy using the available chamber volume and agiven propellant formulation, the charge can be compressed or compacted to higher densities.Conversely, compaction can be used to decrease the volume occupied by the propellant, whilemaintaining the chemical propulsive energy. Simple compaction at room temperature can beused to achieve somewhat higher densities without propellant damage; however, as compactiondensity is further increased, the occurrence of propellant grain fracture becomes more likely,especially ifthe propellant has non-optimal mechanical properties.

Higher compaction densities and greater structural integrity can be obtained if hepropellant is consolidated or bonded during the compaction process. The thermal coatingmaterial that produces bonding of the propellant grains also tends to lubricate the propellant,giving it increased mobility during the consolidation process. Veritay has successfullyconsolidated propellant charges for large caliber ammunition that include a 105-mm tank round,155-mm howitzer charge increment, and a 120-mm tank round (TERM KE). There is also alarge base of experience at Veritay for consolidation of small caliber (5.56-mm caseless round)propellant, which has been consolidated to densities greater than 1.5 gm/cm

3 and mediumcaliber (20 mm, 25 mm, and 30-mm cannon) propellants to densities greater than 1.4 gm/cm 3.With proper grain design and care during the consolidation process, charge densities up to 1.5gm/cm 3 can be achieved with granular propellant for small caliber applications. Thus,consolidation is a method by which the propellant volume can be decreased approximately 30%for most propellant formulations, and in virtually any gun caliber.

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A thermal consolidation process that was developed in France by SNPE (nowEURENCO), licensed in the United States by Veritay Technology, Inc. and subsequentlysublicensed to the U.S. Government, is mature indevelopment and exhibits superiorcharacteristics. The process involves coating propellants with an energetic thermoplasticmaterial that softens when heated. The heated coating material tends to lubricate the propellantand mold during consolidation and forms a dimensionally stable, structurally strong bond whencooled. The bond strength is diminished by only 20% when the consolidated charge is re-heated to 700C, the maximum required ammunition storage temperature. Veritay hassuccessfully consolidated small caliber granular propellants using the SNPE process to adensity of 1.5 gm/cm 3 and conducted firing tests with the resulting charges to demonstrateballistic performance characteristics.Alliant TechSystems/Radford AAP has developed an inert thermal coating for use inpropellant consolidation. This process involves coating propellant with an inert material and

subsequently performing the consolidation operation at elevated temperatures as with theSNPE process. The use of an inert coating material tends to deter or inhibit ignition, dependingon the amount used to coat the grains. Veritay has developed processes to consolidate pro-pellant charges using the Alliant coating for the TERM KE advanced 120-mm tank ammunitionwhere this inhibition effect is desirable.

Because the propellant is hot during the thermal consolidation process, the grains arerelatively soft and easily deformed, which helps to achieve high compaction densities whileexperiencing only minimal (if any) propellant grain fracture. During combustion, the con-solidated propellant charges effectively deconsolidate into the granules from which they wereformed, thereby maintaining essentially the same combustion form function as the loosepropellant prior to consolidation. To date, the thermoplastic coating materials have been appliedto a variety of propellant formulations that include single base, double base, triple base, and lowvulnerability [high ignition temperature (HITP)] nitramine-based propellants. In principle, thecoatings may be applied to almost any propellant formulation.Three single-base propellants coated with the SNPE energetic thermoplastic binder wereselected from Veritay's inventory for use in developing the lightweight ammunition. A fastburning propellant is necessary for small caliber applications where the projectile mass is lowand the action time short. This is especially important because the consolidation process tendsto depress the initial rate of the combustion gas generation due to reduction of the propellantsurface area. Thus, consolidation produces a degree of combustion progressivity independentof the propellant granulation. This is advantageous for consolidated propellant applicationsbecause the initial free chamber volume is low compared to conventional ammunition.An example of the consolidated propellant charge production mold is shown in figure 1.The example of a thermally consolidated propellant charge (fig. 2) illustrates how a granularpropellant is compressed to a high density without significant grain deformation or fracture. The

propellant used during this project was provided by Veritay at no cost to the government.

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Figure 1Propellant consolidation mold

Figure 2Consolidated propellant charge

Lightweight Ammunition Ballistic EvaluationBallistic evaluation of the lightweight ammunition concept was performed using twosingle-shot ballistic test fixtures designed and fabricated at Veritay. Initial interior ballisticdevelopment was performed in a fixture designed to fire the candidate ammunition without acartridge case, using a chamber that replicated the interior dimensions of the cartridge case.

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Excluding the cartridge case from initial testing had two benefits: chamber pressure could bedirectly measured at several locations with piezoelectric pressure transducers, and the cost andtime involved in making cartridge cases could be avoided during the initial development phase.Once the propelling charge was developed, subsequent evaluation of lightweight cartridge casedesigns was performed using a chamber designed for the cased ammunition. Both fixtures useda M240B machine gun barrel, provided by Veritay, which was modified to accept interchange-able chambers.

The single-shot ballistic test fixture for cased ammunition is shown in figure 3. Instru-mentation included a PCB 117 piezoelectric pressure transducer for measuring the chamberpressure through the cartridge case wall, two PCB 119 pressure transducers at down-borelocations, and four Veritay Type-K in-wall thermocouples for measuring barrel heating. Addi-tional instrumentation included optical velocity sensors for measuring muzzle velocity, high-speed photography (fig. 4), and witness cards for determining bullet flight attitude.1A

Figure 3Single-shot ballistic test fixture

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Figure 4High-speed photograph of bullet in flightAn evolutionary approach was taken to the lightweight ammunition development process,with key design parameters defined and varied to gauge their effect on ammunition function andperformance. The ammunition was developed through a process of experimental ballisticevaluation supported by computer simulation using the IBHVG2 (Interior Ballistics of HighVelocity Guns version 2) code. The propellant used for this project was produced for a differentprogram and was not optimized for the current ammunition application. As a result, a propellantmass equivalent to the M80 (46 gr) could not be used without expelling unburned propellantfrom the gun. Therefore, a smaller charge mass than desired (38.8 gr, 15.6% less than the M80)was used during the current program, which resulted in lightweight ammunition performancethat was slightly lower than for the M80. The final lightweight ammunition configuration yielded amuzzle velocity that was somewhat (9%) less than that of the M80.Optimization of a propellant for this application (propellant geometry and formulation)would ensure that all of the propellant is consumed during the ballistic event, thereby increasingmuzzle velocity to levels commensurate with the M80. Alternatively, advanced higher energypropellant formulations would enable the performance goals to be met with a reduced propellantmass, further reducing the weight of the ammunition. Ballistic repeatability measured by peakchamber pressure and muzzle velocity was very good, considering the developmental nature of

the ammunition. A series of pressure time curves for repeat firings of the final ammunitionconfiguration are shown in figure 5.

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CLN

TimeFigure 5

Chamber pressure-time curves for the lightweight ammunitionLightweight Cartridge Case

Much of the weight reduction in the lightweight ammunition developed during this projectwas derived from the use of materials other than brass for the cartridge case. Elimination of thecartridge case altogether (i.e., caseless ammunition) is the ultimate goal; however, a cartridgecase plays an important role in the reliability of the ammunition. Environmental protection is animportant function of the cartridge case, particularly the exclusion of moisture. Mechanicalprotection is also an important function of the cartridge case during shipping, handling, andloading. Cased ammunition has a particular advantage over caseless ammunition when heatmanagement is considered. Much of the heat generated by the burning propellant will becontained within the cartridge case when it is ejected from the weapon, which will reduce theheating rate of the chamber region. In caseless ammunition, the heat will be convected into thechamber, possibly requiring a means of cooling the chamber during sustained firing. Finally, thecartridge case performs the function of sealing the gun chamber and firing pin during a firing. Incaseless ammunition, this function must be transferred to the weapon design, potentiallycomplicating the design and increasing the weight of the weapon itself.

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Research and development of lightweight cartridge case materials has been ongoing formany years and has included study of alternate materials such as aluminum and plastics. Theammunition developed during this project can make use of a variety of alternative cartridge casematerials, including aluminum and polymers. Both aluminum and polymer cases have uniquefailure modes; however, the weapon design can mitigate many of the failure conditions.Regardless of the material type, metallic or plastic, the case material must meet severalrequirements. The case material needs to balance ductility, strength, and toughness to survivethe ballistic event. The material must be able to withstand the thermal input from burningpropellant, as well as from exposure to heated weapon components during burst fire. Chemicalcompatibility with the propellant is very important for the long-term storage of the ammunition.Ammunition Weight Distribution

The combination of a thermally consolidated propellant and a lightweight cartridge caseproduce ammunition with significant weight reduction compared to conventional ammunition.The performance target of this project was to design a 7.62-mm cartridge that weighed at least30% less than the existing M80 cartridge. Considering just the cartridge (i.e., no packaging orlinks), the 7.62-mm lightweight ammunition is 36.5% lighter than the M80 cartridge. If helightweight ammunition is used in a linkless feed system, the weight benefit is even greater,yielding a 45.7% weight reduction compared to the M80 ammunition with M13 links.

Figure 6 shows the weight distribution for the lightweight ammunition developed duringthis project. The total combat load for 600 rounds of ammunition is 21.22 Ibs, not includingpackaging materials. In comparison, the total combat load for 600 rounds of M80 ball ammuni-tion is 33.43 Ibs, not including packaging, and the weight distribution is shown in figure 7.Reducing the ammunition weight by over 12 lbs can significantly reduce the burden on thewarfighter, or conversely, allow the individual to carry additional gear or ammunition. For anequivalent weight, an individual could carry 600 rounds of conventional M80 ammunition or 945rounds of lightweight ammunition, greatly increasing the number of stowed kills.

The charts shown in figure 6 and figure 7 illustrate the weight efficiency of the lightweightammunition compared to conventional brass cased ammunition. The two most importantcomponents of any ammunition in terms of lethality are the bullet and the propellant. An yremaining components present are essentially dead weight that facilitates handling, loading, orignition. Comparing the weight distributions for the lightweight ammunition and the M80, itwasfound that the non-lethality producing components of the M80 consume 50% of the ammunitionweight, while the weight of those components in the lightweight ammunition was reduced to25% of the ammunition weight.

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- Cartridge Case, 4.79,23

oBulets . 12,77, 59 iPropellant, 332 16

QPrimers, 0.34, 2%

Total Combat Load - 21.22 lbs (600 rounds)Figure 6Weight distribution of the Veritay lightweight ammunition concept(packaging materials not included)

0130ets 12 77 ,38

0 Cartrife Case, 10l 2g 49

OPrimenr. 0 43 1

1Propellant 39.4, 12%

Total Combat Load - 33.43 lbs (600 rounds)

Figure 7Weight distribution for the conventional M80 ball ammunition for M240B medium machine gun(packaging material not included)

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Synergistic system-wide weight reduction can potentially be found in several areas. Thereduced size of the ammunition due to propellant consolidation can reduce weapon weight andimprove packaging efficiency. Non-circular cartridge cross-sections can allow even greaterpackaging efficiency. Reduced ammunition weight and increased packaging efficiency willproduce significant improvements in the logistics train. A linkless feed system that is driven bythe weapon can reduce the weight and complexity and improve the reliability of the ammunitionclip or magazine.

CONCLUSIONSThe goal of this project was to design, develop, and test a lightweight ammunition

concept that offered at least a 30% reduction in weight compared to conventional brass-casedammunition, and a substantial reduction in size. It has been demonstrated that the combinationof a lightweight cartridge case and thermally consolidated propellant can produce a weightreduction of nearly 37%, while maintaining ballistic performance. While the work performedduring this project addressed the 7.62-mm caliber, the design con-cepts and lessons learnedcan be applied to other calibers. The ammunition concept discussed in this report can be easilyscaled up or down to the caliber required by the end-user without an extensive re-developmenteffort.

The anticipated benefits of this ammunition concept are: 36.5% weight reduction compared to M80 ball ammunition0 45.7% weight reduction ifa linkless feed system is used0 Ballistic performance equal to M80 ball Scalable to other calibers (smaller or larger) * Reduced cartridge size can lead to reduced weapon weight Reduced cartridge size improves packaging efficiency/reduces

logistics burden * Can enable warfighter to carry additional ammunition or other gear * Cost competitive with conventional ammunition

The benefits of the lightweight ammunition developed by Veritay Technology, Inc.during this project will increase the effectiveness of the warfighter by allowing him to carryadditional rounds of ammunition, or to carry additional gear that will increase combat effective-ness. The technologies employed in the lightweight ammunition are mature, and the ammunitiondesign will scale to other calibers to support a family of lightweight weapons.

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DISTRIBUTION LISTUSA ARDECATTN: AMSRD-AAR-EMK (2)AMSRD-AAR-GCAMSRD-AAR-AEW-M(D), L. Sadowski (5)

AMSRD-AAR-AIJ, J. GoldmanK. SpiegelPicatinny, NJ 07806-5000Defense Technical Information Center (DTIC)ATTN: Accessions Division8725 John J. Kingman Road, Ste 0944Fort Belvoir, VA 22060-6218CommanderSoldier and Biological/Chemical CommandATTN: AMSSB-CII, LibraryAberdeen Proving Ground, MD 21010-5423DirectorU.S. Army Research LaboratoryATTN: AMSRL-CI-LP, Technical LibraryBldg. 4600Aberdeen Proving Ground, MD 21005-5066ChiefBenet Weapons Laboratory, AETCU.S. Army Research, Development and Engineering CommandArmament Research, Development and Engineering CenterATTN: AMSRD-AAR-AEWWatervliet, NY 12189-5000DirectorU.S. Army TRADOC Analysis Center-WSMRATTN: ATRC-WSS-RWhite Sands Missile Range, NM 88002Chemical Propulsion Information AgencyATTN: Accessions10630 Little Patuxent Parkway, Suite 202Columbia, MD 21044-3204GIDEP Operations CenterP.O. Box 8000Corona, CA 91718-8000Veritay Technology, Inc.4845 Millersport Hw yP.O. Box 305East Amherst, NY 14051-0305 11

ad-e403 047__development of a lightweight ammunition concept [2005]

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