Some Comments Regarding Performance Potential for a New Machine Gun and Ammunition Concepts Abe Flatau Consultant

General Outline Summary Introduction Brief Technical Overview Ammunition Emphasis on lightweight, high V0, very low drag projectiles = high kinetic energy to deposit on target Brief Comparison of Trajectory Profiles Proposed vs. current

Conclusion It is strongly recommended that the key technologies be brought together to result in a modern, high performance, effective machine gun system that is a superior weapon in the field.

Summary Conceiving, developing and fielding a weapon system is not an easy task. Perhaps that is why we shy away from replacing tried and tested systems that have been used for almost the past century. This brief presentation points out some of the advances in technology that can be applied to a new high performance machine gun system.

Comments on .50 Cal Heavy Machine Gun Technology from the end of WWI (1918). Cartridge volume is limited. No significant increase in performance. Saboted Light Anti-Material Penetrator (SLAP) performance limited. Overall gun-ammo system limited for performance upgrade.

Aerodynamicist’s Golden Rule “Assume Everything, But the Responsibility.”

Current and Proposed Heavy Machine Gun Systems Wt (lb) V0(ft/sec) US 12.7mm(.50cal) 0.1014 2,800 US 15.24mm(.60cal) US 16.51mm(.65cal) 0.0794 5,000 Soviet 14.5mm(.57cal) 0.1391 3,511 US 29mm M246 0.2267 3,380

Characteristics of Well Designed Tubular Projectiles High muzzle velocity +Low drag shape = High kinetic energy + short time of flight = relatively flat trajectory = high hit probability Performance bonus = high gyroscopic stability = anti-ricochet

Relatively New Technologies (Since Browning .50 Cal was Accepted) Aeroballistic Interior Ballistics Materials (high strength & light weight) Computer Aided Design

Projectiles Tubular w/ Incendiary Pusher/obturator Multipurpose Consumable Conventional w/ HE Charge SLAP

Interior Ballistics Compacted propellant (Proprietary designs and concepts) Ignition Techniques Lightweight projectile Mass (M) + High muzzle velocity (V) = High kinetic energy (1/2MV2) Equates to: Shorter time of flight to a given distance + some aerodynamic lift combined with low-aerodynamic drag = a relatively flat trajectory

Packing Density WWII Propeller Aircraft Jet Fighter

Conclusion It is strongly recommended that the key technologies be brought together to result in a modern, high performance, effective machine gun and ammunition system that is superior to other gun-launched weapons in its general class.

Full-bore Tubular Projectile Configuration Air flow Lip angle Rotating band Crimp groove Boattail Convergent area Throat Divergent area 0173-04

Basic Characteristics of Tubular Projectiles Flight direction Low supersonic drag Light weight allows increased muzzle velocity High gyroscope stability 0171-04

External Flow Characteristics of Tubular Projectiles High Mach Number Low Mach Number M  1.9 Direction of flight Swallowed flow No bow shock on or in front of nose Low drag Choked flow Bow shock High drag 0174-04

Bow shock associated with “choking” and high drag Note: Above shape is known as a Busemann Biplane and also as an “internal” design 0172-04

Before high drag condition Schlieren Photographs of TCD-3 WSCO Supersonic Wind Tunnel Variable Mach Number Operation M  3.0 M  2.5 M  1.6 M  2.0 Before high drag condition High drag condition 0176-04

Aeroballistic Range Photographs/TCD-3 M ~ 40 Near muzzle 20 feet down range 15 feet down range 300 feet down range 0175-04

Tubular projectile M103 case Obturator/ pusher M103 case WSC MAR 76 0183-04

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Potential Advantages of Tubular Projectiles Higher launch velocity (lighter weight) Shorter time of flight Near straight-line trajectory profile Simplified fire control 0170-04

Kinetic Energy vs. Range 500 1000 1500 2000 Range, meters 40 30 25 20 15 10 5 Kinetic energy, ft-lb  103 0.5 sec 1.0 1.5 2.0 2.5 3.0 3.5 4.0 Size Weight, lb Vo, ft/sec 0.65 cal. 0.07940 5000 14.5 mm api 0.1391 3511 0.50 cal. apm2 0.1015 2800 20 mm M246 0.2267 3380 0182-04

T-0.65 Caliber vs. 0.50 Caliber Caliber Weight, lb T-0.65 0.0794 0.50 0.1014 5000 4000 3000 2000 1000 Velocity, ~ft/sec Range, ~meters 0.5 sec 1.0 1.5 2.0 2.5 3.0 4.0 0.7 sec 2.8 0180-04

Representative Trajectory Profiles .50 cal. AP:  = 2, V0 = 2800 FPS .60 cal. TCD-7:  = 0.6, V0 = 5000 FPS 500 1000 1500 2000 40 30 20 10 Horizontal range, ~meters Height, meters Vi.65 cal = 1028 FPS t = 2.60 sec and Vi.50 cal = 815 FPS t = 4.50 sec 0181-04

Summary of .65 Caliber Tubular Projectile Characteristics Significant increase in kinetic energy over .50 caliber Terminal ballistics far superior to .50 caliber AP Flatter trajectory than .50 caliber Shorter time of flight than .50 caliber Greater range than .50 caliber Low weight system/low cost ammunition DRDAR-ACW 0169-04

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“That’s how Research and Development put the pressure on “That’s how Research and Development put the pressure on. First they hustle you to promise them results. Then they hustle you some more to promise them results in our lifetime!” 0177-04