Available

Medium Caliber

Barrel life improvementsNDIA Guns & Ammo

Panama City FL

15-18 April 2002

Presented by: Bob Waterfield

• M242 barrel life history• Barrel life comparison test data

• MK44 • M242 • 27mm

• Test result summary• Comments• Availability status

Outline

M242 25mm Automatic Gun

05000

1000015000200002500030000

M79

2

3HE

to

1AP

3AP

to

1HE

M91

9

M79

1

M91

0

Old

M91

9(H

ES

9053

)

Ammo Types

Ro

un

ds

of

Bar

rel L

ife

NitridedChrome Plated Future High

Performance Ammo

2600KFlame Temp

3000KFlame Temp

3600 + KFlame Temp

^ REQUIREMENT ^

MK44 test schedule

A mixture of SS, 3 round & 5 rounds bursttotaling 198 rounds in 27.5 minutes

and cool to ambient

• 66 rounds in 2.5 minutes• 10 minute cool

• 66 rounds in 2.5 minutes• 10 minutes cool

• 66 rounds in 2.5 minutes

30mm MK44 barrel BG-10 results

Nitride bore at 5,000 rounds

Wearout Curve

Chrome bore at 21,000 rounds

30.0

30.1

30.2

30.3

30.4

30.5

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

BG-10 Position

Bo

re D

iam

eter

(mm

)

Forcing Cone Erosion vs. Rounds Fired

204.0 mm wearout limit

5,500 round lifeMK44 Nitride

21,000 rounds firedMK44 chrome

25,000 + round lifeMK44 chrome

projected

190

195

200

205

046

113

1321

6630

7839

3047

1155

358,0

218,9

039,7

5510

,607

11,45

912

,311

13,16

314

,015

14,86

715

,949

16,80

117

,65318

,505

19,35

720

,209

21,04

222

,000

23,00

024

000

2500

0

Rounds Fired

Dis

ttan

ce t

o 3

0.37

5mm

dia

met

er

M242 test schedule

A mixture of SS, & 10 rounds bursttotaling 300 rounds in 34 minutes

and cool to ambient

• 150 rounds in 2 minutes• 30 minute cool

• 150 rounds in 2 minutes

24.8

24.9

25

25.1

25.2

25.3

25.4

25.5

25.6

25.7

25.8

25.9

26

26.1

26.2

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

BG-10 Position

Bo

re D

ia. (

mm

)25mm M242 barrel BG-10 results

4,500 round life Nitride bore

6,500 round life US Army Chrome

Wearout Curve

Boeing Chrome at 6,500 rounds

Boeing Chrome at 14,000 rounds

25

25.2

25.4

25.6

25.8

26

26.20

774

2173

3416

4659

6045

7328

8591

9834

1111

7

1238

0

1334

3

1391

6

1480

0

1620

0

1760

0

1880

0

2000

0

Rounds Fired

Bo

re D

iam

eter

(m

m)

Position 1 Ø (@158mm) vs. Rounds Fired

Wearout limit for position one4,500 round lifeNitride bore

6,500 round lifeUS Army chrome

14,000 rounds firedBoeing chrome

20,000 + round lifeBoeing chrome

projected

140

145

150

155

1600

774

2173

3416

4659

6045

7328

8591

9834

1111

7

1238

0

1334

3

1391

6

1480

0

1620

0

1760

0

1880

0

2000

0

Rounds Fired

Dis

tan

ce to

25.

99m

m d

iam

eter

Forcing Cone Erosion vs. Rounds Fired

156.5 mm wearout limit 4,500 round lifeNitride bore

6,500 round lifeUS Army chrome

14,000 rounds firedBoeing chrome

20,000 + round lifeBoeing chrome

projected

BK27 test scheduleFour (4) one second bursts of 30 rounds each

totaling 120 rounds in 7.5 minutesand cool to ambient

• 30 round burst in one second• 2.5 minute cool

• 30 round burst in one second• 2.5 minute cool

• 30 round burst in one second• 2.5 minute cool

• 30 round burst in one second

Wearout Curve

Existing Production Barrel at 461 rounds

Boeing Chrome at 941 rounds

Boeing Chrome at 461 rounds

27mm Preliminary test results

M242 25mm Automatic Gun

05000

1000015000200002500030000

M79

2

3HE

to

1AP

3AP

to

1HE

M91

9

M79

1

M91

0

Old

M91

9(H

ES

9053

)

Ammo Types

Ro

un

ds

of

Bar

rel L

ife

NitrideUS Army ChromeBoeing Chrome

Future HighPerformance Ammo

2600KFlame Temp

3000KFlame Temp

3600 + KFlame Temp

^ REQUIREMENT ^

Boeing’s chrome process increases life• Greater than 4x compared to our baseline

nitride.– 30mm MK44 barrels– 25mm M242 barrels

• Greater than 3x compared to existing M242fielded barrels

• Greater than 4x Compared to existingBK27 fielded barrels

Test result summary

• Current fielded M242 barrel does notmeet Bradley MN barrel liferequirement with present ammo mix.

• Boeing manufactured chrome barrels– Exceed MN requirement– Will reduce life cycle cost & logistical burden–Allows for increased performance

(higher flame temp.) propellants.

M242 Comments

MK44 Chrome barrelsAvailability status

MK 44 barrels in production withdeliveries on going for

US NavyUS Marines

Norwegian ArmySwiss Army

Finnish Army

M242 & 27mm AircraftChrome barrels Availability status

MK 242 barrelsProcess established

Awaiting kick off customer

Advanced 27mm Aircraft barrelsProcess established

Ready & waiting for JSFor

Any other Kick off customer