GAU-19/A Barrel Life StudyJames St. Germain

40th Annual NDIA Armament Systems GDARM ConferenceNew Orleans, Louisiana April 2005

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GAU-19/A Barrel Life StudyAgenda

GAU-19/A DescriptionBarrel Design ParametersCustomer BackgroundBarrels Used in the StudyBarrel Inspection & ResultsBarrel Testing & ResultsConclusion

40th Annual NDIA Armament Systems GDARM ConferenceNew Orleans, Louisiana April 2005

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GAU-19/A Barrel Life StudyGAU-19/A Description

Three-barrel 12.7mm externally powered Gatling gunProvides lightweight, lethal firepower to a variety of platforms:

HelicoptersGround vehiclesNaval vesselsHigh speed patrol boatsFixed Wing Aircraft

40th Annual NDIA Armament Systems GDARM ConferenceNew Orleans, Louisiana April 2005

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GAU-19/A Barrel Life StudyGAU-19/A Description

40th Annual NDIA Armament Systems GDARM ConferenceNew Orleans, Louisiana April 2005

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GAU-19/A Barrel Life StudyGAU-19/A Description•Rate of Fire 1000/2000 spm (1,300 spm HMMWV)•Effective Range 1800 Meters•Maximum Range 6000 Meters•Max Dispersion 5 mrads (80 % circle) = 5m at 1000m•Weight 138 Lbs (gun & feeder assembly)•Reliability 40,000 MRBF•Average Recoil 600 Lbs at 2000 SPM•Maintenance 30,000 rds.•Barrel replacement 50,000 rds. per set•Sighting Holographic, NVG compatible, Laser Pointer•Uses entire range of .50 cal NATO / Mil Spec ammunition

40th Annual NDIA Armament Systems GDARM ConferenceNew Orleans, Louisiana April 2005

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GAU-19/A Barrel Life StudyInitial Barrel Design Parameters

Crack Propagation Program utilized for barrel analysisEach barrel set must be capable of firing out a complete ammunition container loadTarget life expectancy of 35000 rounds per set used in analysis program

40th Annual NDIA Armament Systems GDARM ConferenceNew Orleans, Louisiana April 2005

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GAU-19/A Barrel Life StudyBarrel Physical Description

Mat’l: CrMoV steel per A10505Bore: Chrome plated per A10374Exterior Finish: Solid Film Lubricant 119A211512.69 mm bore/12.98 mm groove diameter8 land rifling: right-hand constant twist 1 turn in 30 calibers

40th Annual NDIA Armament Systems GDARM ConferenceNew Orleans, Louisiana April 2005

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GAU-19/A Barrel Life StudyCustomer Background

40th Annual NDIA Armament Systems GDARM ConferenceNew Orleans, Louisiana April 2005

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GAU-19/A Barrel Life StudyBarrels Used in Study

Barrel sets from customers with 35,000 to 54,000 roundsTypical firing cycles of 50 to 100 roundsAPI ammunition

Barrel set from GDATP with 50,000 roundsTen 800 round bursts with all others at 200 to 400 roundsM33 Ball and M17 Tracer, 4:1

40th Annual NDIA Armament Systems GDARM ConferenceNew Orleans, Louisiana April 2005

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GAU-19/A Barrel Life StudyParameters Measured

InspectionErosion

Indicator of velocity reductionCrack Depth

Indicator of rounds to failureTest

VelocityIndicator of barrel performance and resultant targeting

40th Annual NDIA Armament Systems GDARM ConferenceNew Orleans, Louisiana April 2005

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GAU-19/A Barrel Life StudyParameters Measured – Barrel Erosion

Barrel Serial#1000003 50,000-rds. per set

Washout area from 800-rds. fireout bursts. More severe than other two barrel samples that were used by customer in combat and practice.

40th Annual NDIA Armament Systems GDARM ConferenceNew Orleans, Louisiana April 2005

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GAU-19/A Barrel Life StudyParameters Measured – Barrel Erosion

Bore Erosion .50 cal barrels

0.010

0.015

0.020

0.025

0.030

0.035

0.040

0.045

0.050

0.055

0.060

1.0

5.0

10.0

20.0

25.0

26.0

27.0

28.0

29.0

30.0

30.5

31.0

31.3

31.5

31.8

32.0

Distance from muzzle (in)

Gag

e re

adin

g

54 k Roundsper set

48 k Roundsper set

43 k Roundsper set

35 k Roundsper set

40th Annual NDIA Armament Systems GDARM ConferenceNew Orleans, Louisiana April 2005

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GAU-19/A Barrel Life StudyParameters Measured – Crack Propagation

1000273 53000-rds per cluster Cut plane @ 4.4 “ Crack depth .020 “

40th Annual NDIA Armament Systems GDARM ConferenceNew Orleans, Louisiana April 2005

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GAU-19/A Barrel Life StudyParameters Measured – Crack Propagation

.50 Cal. Barrel Life Analysis

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0 20000 40000 60000 80000 100000 120000 140000

Rounds fired per barrel set

Cra

ck d

epth

(inc

hes)

Barrel 3 .0118 init crackColumbian barrel .006 intial crackLil Bird barrel .004 initial crack

40th Annual NDIA Armament Systems GDARM ConferenceNew Orleans, Louisiana April 2005

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GAU-19/A Barrel Life StudyParameters Measured - Velocity

Yaw present, tracer only

215054000

Yaw present, tracer only

221053000

Two minor yaws, tracer only

256548405

No yaw265545200

No yaw268043250

No yaw28004000

YAW RESULTSVELOCITY(ft./sec.)

ROUNDS AS RECEIVED

(per barrel cluster)

40th Annual NDIA Armament Systems GDARM ConferenceNew Orleans, Louisiana April 2005

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GAU-19/A Barrel Life StudyConclusion

At approximately 50,000 roundsSignificant velocity changeYawing begins to occur in tracers affecting targetingNo danger of crack propagation causing failure

BARREL REPLACEMENT PER ROUNDS FIRED CAN BE INCREASED FROM 35000 TO 50000 ROUNDS PER SET