765459 limited analysis of a new ammunition concept

8/11/2019 765459 Limited Analysis of a New Ammunition Concept

1/38

V

AD-765

59

A

LIMITED

ANALYSIS

OF

NEW

AMMUNITION

CONCEPT FOR

OTENTIAL FUTURE

RI~LE

APPLICATION

Richard Kwatnoski

et

l

Frankford

Arsenal

Philadelphia Pennsylvania

June

1973

V

D I S T R I B U T E D

B Y :

Km

a t i o n a l

T e c h n i c a l

I n f o r m a t i o n

S e r v i c e

0 .

.

E P A R T M E N T

F

O M M E R C E

5285

Port

Roya l

Ro ad ,

Springfield

V a .2151


2/38

MEMORANDUM

REPORT

M73-I2-1

AD

05

o

A

LIMITEDANALYSISOF

A

NEW

AMMUNITION

CONCEPT

FOR

POTENTIALFUTURERIFLEAPPLICATION

by

RICHARD

KWATNOSKI

ROBERTMcHUGH

June1972

NATIONAL

TECHNICAL

INFORMATIONSERVICE

i

5

C-z:


3/38

DISIOSITION

INSTR

UCTIONS

Destroythis

eport

v/hennolongerneeded. Donotreturn

it

to

the

o.-iginator.

A

The

findingsnthis

eportare

notto

be

cons

-i-od

as

an

officialD;

partmenfc

ofthe

Army

position

unless

sodesignatedbyother

uthorize

documents.


4/38

UNCLASSIFIED

SecurityClsulflcstton

I

OCUMENT

CJh

KOL

DATA-R&D

(Sicuillr

clmt

lletl

in

olttllt.

odyo/Mlrclmnd

Initti

li irnelillonwu.

enitll

trpeil

It

)III)H04.11.232

.

OROJCCT

NO.

DA

Project-

1J562604

.010

it.

TOTAL

.C.

OF

PA.CCJ

lb.NO .OFRCF*

5

t .ORIGINATOR'*

REPORTNUM*RERIS)

?

A.

Memorandum

Report

M73-12-1

17

3TNCR

nEPORT

NOItif/injrKMiwaHN

autmr

Ml#lW

hUnpett)

10 .

OISTRIBUTIOHSTATEMENT

Approved

for

publ

;

.c

release;

distribution

>nlimited.

II. SUPPLEMENTARY

NOTES

i:

ONSC 'NO

MILITARYACTIVITY

SASA

IS. ASSTRACT

An

analytical

tudy

was

conducted

by

he

Ballistics

and

Analytics

Branch,

FrankfordArsenal,

or

hepurposeof

developing

a

new,lowengineering

risk,ow

impulseammunition

concept

as

a

potentialcaniidafceorheutureifleSystem

(FRS).

Tne

ammunition

or

thisnewystem,

Jesignated

as

uture

mmunition

forBurst-RifleLaunchFABRL),as

analyticallydevelopedasa

,7 .1

rain,

AR2

hapa,

i > .

> b

mm

projectile

with

the

amemuz-rievelocityandrajectory

aa

the

tandard

5.

56

mmM193projectile.

A

larg.-

numberofcandidate

FABRL

designs

weregenerated

and

analyzed,

nd

everalofthe

designs

appearvery

promisingormeeting

required

performancecriteria

cr

theriflerole.

In

ad-

dition,

onedesign

could

beconsideredorboth

th.j

rifleandmachineguroles.

"f\

*MM

JO RFLACSOOFORM l?S.

U}

|IMVll4>3

OSMLSTI

FOR

AROYUSE

I JAN4.WHICHS

UNCLASSIFIED

entity

CUsslflcaUon

Ou,


5/38

UNCLASSIFIED

Security

Claatlticttlon

v * LIMN

tl C

ROIL

XT

note

T

HOLF

Hi

Future

Rifle

1

T

Low

Impulse

Fumer

i

Burst-fire

A

R-Shape

i ,

'

i

AR-Bullet

i

i

i

s

'

1

i

i

I

|

P

i i

>

i

i

{

1

'

j

i

i

j

: |

|

N

>

if

i

i

j

i

i

i

i

i

UNCLASSIFIED

K

SecurityClaaairicatlon


6/38

MEMORANDUM

REPORT

M73-12-1

A

LIMITED

ANALYSIS

OF

A

NEWAMMUNITIONCONCEPT

FOR

POTENTIAL.FUTURERIFLEAPPLICATION

by

RICHARD

KWATNOSKI

ROBERT

McHUGH

AMCMS

Code:

662604.11.

232

DAProject:1J562604

A010

\A

- |

I

m

n

f

Approved

forpublic

release;

distribution

unlimited.

Munitions

Development

ngineering

Directorate

FRANKFORD

ARSENAL

Philadelphia.

PA

9137

June

973


7/38

I

I

I

L

ABSTRACT

An

analytical

tudy

was

conducted

by

the

Ballistics

and

Analytics

Jranch,

Frankford

Arsenal,

or

the

purpose

of

developing

new,

low

engineeringrisk,owimpulseammunition

concept

asa

potential

can-

didate

or

theFuture

Rifle

System

FRS). TheammunitionorhiB

new

system,esignatedasFuture

Ammunition

for

Burst-Rifle

Launch

(FABRL),

as

analyticallydeveloped

asa

37.

1rain,R2

hape,

5.

56mmprojectilewith

the

ame

muzzle

velocity

andtrajectory

as

thetandard

5.

56mmM193

projectile.

A

largenumber

of

candidate

FABRlidesignswere

generated

andanalyzed,andeveralofthedesigns

appearvery

promisingformeeting

required

performancecriteria

or

theriflerole. Inaddition,

ne

design

couldbeconsideredorboth

the

rifle

and

machine

gun

roles.

(


8/38

FOREWORD

The

contributions

f

Mr.

ichard

Grant,

5100,

n

the

preparation

of

the

drawingsnd

curves

or

thisreportaregratefully

acknowledged.

iii


9/38

TABLE

OF

CONTENTS

I

w

f

INTRODUCTION

CONCEPTANALYSIS

PROJECTILEDESIGN

AND

MATERIAL

CONSIDERATIONS .

.

DISCUSSION

CONCLUSIONS

RECOMMENDATIONS

APPENDIXA-

Twist

RateEstimates

APPENDIXB-Drag-reducingFumerEffects

REFEREN ES

DISTRIBUTION

Listof

Illustrations

Figure

1.

rojectileShapes

Studiedby

Ballistic

ResearchLaboratories

2.

.

56mmAR2

Shape

Projectile

.

3.utureAmmunitionfor

Burst-Rifle

Launch

Design

)

4.

uture

AmmunitionforBurst-RifleLaunch(Design2)

5 .

uture

Ammunition

or

Burst-Rifle

Launch

Design

3)

6.

uture

Ammunition

for

Burst-Rifle

Laur-chDesign

4)

7.

uture

Ammunitionor

Burst-Rifle

LaunchDesign5)

18

M

L )

K

:

u

1/

iv


10/38

Lift

of

Illustrations

Cont'd

.

figure

aj

8 .utureAmmunitionforBurst-RifleLaunch

Design

6) .

9.

uture

Ammunition

for

Burst-Rifle

Launch

Design

7)

.

4

10 .

uture

Ammunitionfor

Burst-Rifle

Launch

Design

8 )

.

* 5

11 .utureAmmunitionfor

Burst-Rifle

LaunchDesign9) .6

B-l.

Velocity

vsRange 4

B-2.

EnergyvsRange 5

B-3.

Velocity

vs

Range

6

B-4. Energy

vs

Range 7

ListofTables

Table

I.allistic

nd

Physical

Parameters

II.

aterials

nd

Densities

Used

in

FABRL

Design

Study .

.

.

A-I.

Twist

RatesRequired

for

StableLaunch

ofFABRLDeaigns

1


11/38

INTRODUCTION

In

February

1971,

heBallisticResearchLaboratory(BRL)

publishedtheresultsofacomprehensive3tudy

of

the

ballistic

properties

of

a

broad

spectrumof

projectile

shapes(Figure

)

which

included

various

calibers

elocity

levels,

nd

material

densities.

A

drag-reducing

tracer

(or

"fumer")

wasalso

studiedasa

promising

method

for

reducing

projectile

basedrag. The

projectilethat

generated

themost

interest

was

an

artillery

shape

designatedastheAR2hape.

This

projectile

n5.

56

mms

made

fromcopperplated

steel

and

weighs

thesame

as

thestandard

5.

56

mm,

55

grainMl

c

;3

ballbuliet

(Figure2).

TheAR2hapewas

of

interest

because

of

its

favorable

dragcharacteristics

which

are

significantly

superior

to

thestandard

Ml

93bullet.

Considerable

attention

hasbeengiven

o

examining

the

feasibility

of

utilizingthe

AR2

shape

projectile

for

the

Squad

Automatic

Weapon

System

(SAW),

here

ong

range

performance

requirements

havebeen

documented. However,

he

interest

that

prompted

the

design

study

presentedhereinwasbasedondeterminingthefeasibility

of

utilizing

theAR2shape

projectile

forshorterrangeapplications, suchashe

Future

Rifle

System(FRS).

CONCEPTANALYSIS

An

analytical

studywas

undertakenby

Frankford

Arsenalforhe

purposeof

developing

a

new

conceptasa

potential

candidate

for

the

future

rifle

system. This

new

concept

has

beendesignated

aa

uture

AmmunitionforBurst-Rifle

Launch(FABRL). This

tudypresents

the

meritsof

trading

off

aportion

of

thesbenefits

attainable

byutilis-

ingthelow-dragAR2shapeforareducedweight,ow-impulse,

urst-

fireriflesystem.

As

with

any

systemsdesignstudy,ertainconstraints

mustbeestablished. Thenitialconstraintsappliedtothistudyareas

follows:

L.

C.MacAllister,t

al,

A

Compendium

of

Ballistic

Propertiesof

Projectiles

of

Possible

Interest

inSmallArms,"Ballisticesearch

LaboratorieseportMo. 1532, February1971.


12/38

e *

FLI

CB2

CB3

CC2

c

AR1

AR2

Figure

. ProjectileShapes

Studied

by

BallisticResearch

Laboratories


13/38

;

i

u

A

u

S k

tt

s


14/38

1.

.56

mm

caliber,

2.8.6

nch

barrel

travel,

3.

rajectory

comparable

totheM193

ball

bullet,

an d

4.

uzzle

velocity

of

3270

fps

same

as

he

Ml93).

The

first

an d

econdconstraints

werebased

uponconsiderable

interest

inutilizing

he

M16AI

ifleorits

basic

mechanism

or

futurerifle. The

ast

twcconstraints

were

based

upon

theUser's

acceptanceof theperformance

characteristics

oftheM16A1

ifle.

The

exteriorballisticparameters

orthe

AR2

hape

.56

mm

projectile

were

calculated

rom

results

ofactual

firingsonducted

y

BRLi.

Usingtheseparameters,

he

analysisndicated

required

bullet

weightof

37.1rainro

melt

initial

constraintsandmen-

tioned

above.

Thisrepresentsa

3percent

weightreduction

from

the

t-*ndard

M193

ball

bulletor

copper

plated

teelAR2

hape

bullet.

Interior

ballistic

parameters

or

-tFABRL

systemwerecalculated

according

totandardtechniques.

Recalling

that

the

FABRL.

iso

be

ow

impulse

ystem,

interiorballisticparametersweregen-

erated

with

anadditional

constraint

that

the

muzzleimpulsenot

exceed0.80

pound-seconds.

The

resultsofexterior

ndinterior

ballistic

calculations

nd

otherparametersofinterest

arehown

in

Table

. Information

for

the

tandard

M16A1ystemisalsohown

in

Tablewhichalso

illus-

trates

everal

important

advantages

of

the

FABRL

conceptover

he

standard

VI16A1

ystem.

The

FABP.L

conceptcould

result

in

a

con-

siderably

lighterystem

whiletill

maintaining

theamemuzzlee lru

ity

ndtrajectory

as

heM193

ballbullet.

The

requiredchamberpros-

surc

of

39,

500

psi

could

enhanceheeasibilityofutilizinglightwciKb'

casematerials

oruture

ystem.

F.vpn

fa

hra'i?

ra *

was

equire

forhe

FABRL

cartridge,overall

cartridgeweighthould

bereduced

by

approximately30

percent

from

thatof

the

.56

mmM193

cartridu'-.

2

M.

J .

Piddington,

T.

H.

Oertel,

E.

L.

Herr,

and

W.J.

Bruchey,

''Experimental

Ballistic

Propertiesof

Selected

ProjectilesofPossible

Interestin

Small

Arms"U), Ballistic

Research

LaboratoriesMemoran-

dumReportNo.194,June1972.CONFIDENTIAL

^"Interior

BallisticsofGuns,

"Army

MaterielCommand

Pamphlet

AMCP

706-150,

February

1965.


15/38

r

TABLEI.

Ballistic

nd

PhysicalParameters

P.iramers.*

1.

aliber

2.uzzlevelocity

3.

rojectile

weight

4.

/D

ratio

5.

allistic

oefficientC

7

)

6.

orm

actor

7.arreltravel

8.

harge

weight

9.

verage

peak

chamber

pressure

10.Muzzle

impulse

FABRL

System

Ml6

Sy3tcm

AR2

Projectile

M193Projectile

5.

56

mm

5.56mm

3270.

0fps

3270.0

fps

37.1gr

55.0gr

S.5

3.3

0.126

0.126

0.845

1.241

18.6n.

18.6

n.

15.0gr

28.

5gr

39.5kpsi

52.0

kpsi

0.80

lb-bee

1.23

b-sec

Themost

ignificant

advantage

of

the

FABRL

ishe

relatively

low

muzzle

mpulseof

80

pound-seconds. This

mpulseevel

alc^

compares

favorablywiththe

currentSerial

Flechette

RifleSFR)

and

Serial

Bullet

RifleSBR)candidates

or

heuturerifle

program.

Reduced

mpulse

systems

have

experimentally

demonstrated

ignificant

increasesnhit

probabilities.

Thereduced

impulse

evels

of

the

FABRL

ystemarc

attainable

without

reliance

upon

mall

bore

ystems

and/or

projectile-

tjabot

assemblies.

Theseare

he

primary

actors

or

considering

the

FABRL

conceptas

a

low

engineeringriskforthefuturerifleprogram.

The

major

potential

drawbackof

the

FABRL

is

hat

t

would

have

almost

one-third

ess

trikingenergy

at

any

givenrange,hen

compared

totheM193.However,ncapacitationprobabilitiesareafunctionoftin:

energy

ransferred

to

he

target

nd

the

hit

probabilities.

The

ncreased

hit

probabilities

of

the

FABRLsystemhould

offset

the

reduction

in

striking

energy.

Striking

energy

reductionscould

be

offsetfurther

by

increasing

thepercentageofenergy

transferred

efficiency)to

a

oft

target.


16/38

}

PROJECTILE

DESIGN

AND

MATERIAL

CONSIDERATIONS

u

The

exploratorydevelopmentof the

FABPJL

concept

was

nitiate* .

ia

a

comprehensive

designstudy,

o

generate

a

number

of

37.

gr

5 .

56

mm

AR 2projectiledesigns. Theprimaryobjective

v/as

dirtctfl

toward

establishing

aprojectile

designcapableof

transferring

ea . - - . f i

ble

percentageofitsenergy

insofttargets,

hile

maintaining

hard

targetpenetrationcapability.

Theprojectiledensityrequiredby thefixedweighta n dexterior

configurationis

relatively

low,

hus

ruling

out

the

utilization

of

con -

ventional

lead

core

(jacketed)

and

solidsteel

core

(copperplated)p>

jectiles.

This

restriction

required

the

investigation

of

anumber

;

materials

for

which

little

information

is

known

abouttheir

lethal

properties.

Also,

since

analyticalcapabilities

forpredicting

ethalityhaven o t

advanced

sufficiently

toprovideadequatedesign

criteria,

he

nature

o f

thisdesignapproachishighly

exploratory. Lightand

soft

materials

could

behave

favorably

in

softtargets, but

the

requirementforpene-

trationof

helmetswithlinersmust

also

be

considered.

This

dualrequirement

led

to

consideration

of

a

number

o f

design . - .

ofhybrid

construction,ith

steel

considered

as

the

primary

materi.-l

for

maintaining

helmet

penetrationcapability.

Depicted

uranium

/n r

also

considered,

ince

its

high

density

increasesthe

amount

o f

light

material

that

can

be

used

in

a

hybrid

FABRL

design.

However,

he

potential

problems

associated

withthe

use

ofdepleteduranium,may

yieldresultswhich

are

purely

academic.

Other

dense

materials,uch

as

ungsten,antalum,tc.,

ere

eliminatedbecause

of

theirhigh

co3t.

everal

of

the

hybrid

designs

generated

todateemploy

plastic

materials.ertainplastic

materials

have

proven

satisfactoryforbullet

engraving

n

rifled

barrels.

he

average

density

forthe

plastic

consideredwas278

grains/inch^

t h < _ '

approximate

density

ofpolycarbonate).

Composite

materials,

such

a 3

plastic/metal

powders,erealso

considered.

The

economy

a n dproductionfeasibility

of

these

materfoK

were

demonstrated

withthe

adoption

of

the

Cartridge,

aliber30 ,


17/38

Frangible,

all,

M22. The

rangible

material

usedfor

theM22

bullet

was

alead/bakelite

composite50

percent

each

material,y

volume).

Thedensityof

the

rangiblematerial

was

ixed

at1189grains/Inch

5

.

Lead

oriron

powder

couldbe

usedwiththe

bakelite

or

any

other

suitable

plastic).

Aummaryofthe

materials

consideredand

theirrespective

ensities

s

giveninTable

I

TABLEII.

MaterialsandDensities

Used

inFABRL

Design

Stvdy

Density

Material

(gr/in.

3

)

Steel

I960

Lead

2846

Uranium

4402

Gilding

metal

2226

Plastic

278

Composite

frangible)

1189

Withinthisbroad,generalized,

analytical

designtudy,ine

FABRL

designs

were

generated.

These

are

hownin

Figures

through

11.

Thegyroscopictabilitycalculationsare

hown

inAppendixA

for

each

of

the

designs.

DISCUSSION

TheFABRLdesigntudy

presented

herein

isnot

meant

to

e

completenalystsof

all

thepossibleapproaches,nor

hould

these

designs

be

consideredinal. However,ananalysisof

a

broadpec-trim

of

possibilities

s

presented.

In

addition,

any

number

of

new

designs

couldbegeneratedbyusing

the

nformation

presentedhereinas

basis. The

primary

intent

n

early

disseminationof

this

nformation

is

to

express

a

receptivenessocommentsor

alternate

designideas

fromotheragencies.


18/38

[

a

u .

0

P

.c

u

c

J

6 )

G

n

03

o

3

o

a

a

3

o

t-

3

St


19/38

8 .

C l

Q

J2

O

4 )

h

e

o

s

h

3

of


20/38

c

o

0

P

,4

o

I

I

4 ->

en

^ <

o

c

o

S

s

a )

u

ex

10


21/38

i

Q

X

I

i

-J O

a

c

1

I

1)

4)

n


22/38

1 0

to

4)

Q

o

0 1

u

0

I

5

e n

12


23/38

V|

s -.

a

50

r


24/38

c

to

09

4)

C

u

q

3

a

n

CQ

t-

O

C

0

I

i

4)

h

i

14


25/38

CO

a

03

a

Q

V

2

i

(0

0 )

15


26/38

16

O

Q

o

i

i

i

a

s


27/38

t

s

ecognized

that

certain

engineering

problemareas

are

ssociatedwith

number

oftheFABRLdesigns. Theseproblem

reas

will

be

addressed

as

developmentprogrecaes. Forexample,

the

potential

problem

of

ecuring

a

gilding

metal

cup

on

the

base

nd

bourrelet

of

esign

4

Figure6)

must

be

addressed.

FABRL

designs

2

{Figure

4)

and

Figure

)

are

presented

tollustrate

extreme

con-

ditionsofplasticthicknesson

the

bourreletof

the

teel

bullet.

A

modification

ofthese

wo

designs

may

provemere

desirable

than

either

of

the

two

extreme

conditions.

Designs

Figure

3)and

Figure

7)appeartobeatisfactoryor

experimental

fabrication

and

testing.

Designs

Figure

)

andFigure

9)

appear

to

present

nomajor

engineeringproblem

areas,

assuming

the

objections

totheuseof

depleted

uranium

can

be

overcome.

DesignsFigure

10)

nd

Figure11)

would

not

present

ignificant

problemsn

the

manufactureofexperimentalquantities. However,

in

mass

production,he

orming

of

cavities

n

solid

teeland

the

necessity

forcopperplating

could

prove

detrimental.

Design

8,

incorporating

traceror"fumer"),

ould

be

especially

interesting

becauseof

the

potential

base

drag

reduction. Also

coupled

withthe

technologybeing

developed

under

he

Drag

ReducingFumer

StudyDRFS),

designcould

result

inanextremelylow

dragpro-

jectile,

especiallyince

hebase

drag

oftheAR2hape

sapprox-

imately

60

percent

of

the

overall

drag.

At

the

risk

of

being

pre-

mature,t

isconvcivablethatdesign8,

employingdrag-reducing

fumer,ouldbeutilizedas

botha

FRScandidate

and

higher

riskSAW

candidate.

Additional

nformationonthis

conceptis

presentedin

Appendix3 .

AI30

worthy

of

note

areome

of

the

extremely

high

twist

rates

requiredornumberof

thedesigns

AppendixA). Someof

these

twist

ratescouldbe

tretchingthe

tate-of-the-artnbarrelmanu-

facture.

This

problem

areav/illbe

addressed

with

Rock

IslandArs-n;i l

as

he

program

progresses.

In

addition,

he

high

twistrates

required

for

table

launch

of

several

FABRL

designs

may

cause

problem

are.is

in

bullet

tructural

integrity,especiallythosewithplasticengraving

surfaces. However,plasticbourrelethouldofferreducedbarrel

erosion.

17


28/38

CONCLUSIONS

Ananalytical

design

tudywas

undertaken,

and

results

of

this

study

illustrate

thepotentialfor

anew,ow-risk

contender

or

he

Future

Rifle

System

FRS).

This

new

ystem,

esignated

as

Future

Ammunition

for

Burst-Rifle

LaunchFABRL),

erives

ts

maximum

benefit

rom

ts

verylow

impulseevel

of

80

pound-seconds.

The

impulse

evel

of

the

FABRL

wouldbeignificantly

lower

than

the

standard

M16A1

ystem

and

comparable

to

the

SerialFlechette

Rifle

(SFR)

andSerial

Bullet

Rifle

SBR).

Inaddition,

he

FABRL,employ-

ing

a

37.1rain

AR2

hape

projectile,

ould

offer

alightweight

ystem

an d

the

urther

possibilityof

employing

lightweight

cartridgecase

materials.

However,

xtensivemodifications

o

he

M16A1ystem

would

probably

be

required

tomaket

compatable

with

the

FABRL.

A

number

of

basicprojectiledesignswere

generated

during

the

study,threeofwhichappear

to

bemostpromisingor

experimental

developmentandevaluation.

These

three

designsare

the

teelcore/

frangible

jacketdesign

5),

steel

core/plastic

acketdesign

1),

nd

the

olid

teel

projectiledesign)

employing

drag-reducing

tracer

or

umer.

Designwould

greatly

mprove

he

owertriking

energiesas-

"^ciated

with

the

FABRL. Design8

might

also

offer

the

potential

or

a

common

cartridgeapproach

to

both

the

FRSand

the

higherrisk

portionof

the

SAW

program.

This

s

discussed

in

greater

detail

in

AppendixB.

REC

OMMENDATIONS

1.

xtensivehardware

exploration

of

the

FABRL

concept

hould

be

pursuedcurrently

programmed

under

Task

1

of

Project

A010

or

FY

73

and

FY

74).

This

exploration

hould

include:

a.

xpansion

of

theprojectile

design

tudyinan

attempt

to

generate

additional

projectileapproaches.

b.onducting

a

materials

earch

and

manufacturing

experi-

mentalquantities

of

FABRLdesigns.

18


29/38

c.

Conduc t ingteatstoevaluate

FABRLaccuracy,

ullet

integrity,

rajectory,

ethality,nd

penetration.

2.

iventhedatafrom

rbove,

ndcoupled

with

the

data

con-

tainedherein,

n

extensive

ystems

analysist udyhouldbeonduc t ed

to

assess

he

merits

of

the

FABRLconcept

ascontenderfor

the

Fu tu r e

Rifle

Program.

3.

ABRLdesign8 ,

ith

a

drag-reducing

tracer

or

fumer),should

beevaluatedforacommoncartridgeapproachtoboththeFRS

an d

higher

risk

portion

of

theSAWprogram.

19


30/38

APPENDIX

Twist

Rate

Estimates

Barrel

twist

rates

required

for

agyroscopic

tability

factor

of.

50

were

calculated

forall

of

the

FABRL

designs.

Standard

techniques

wereusedforthe

twist

rate

calculations.

The

JSMOMNT

computer

program

was

used

tocalculateprojectile

weight,

enter

of

gravity,

and

moments

ofinertia.

The

normal

forcecoefficient

and

center

ofpressurefor

the

5.

56

mm

AR2

hape

projectilewere

estimated

from

the

values

calculated

by

BRJL.

*

The

tandard

formula

forgyroscopic

tability

factorwasmodifier

(ashownbelow)tofacilitatetwist

rate

calculations.

where:

T

3

=

8fflx

2

pd

3

Cj Sgly

T

wist

rate

inches/turn)

Sg

yroscopic

tability

factor

assumedequal

to

1.50)

p

ir

densityassumedequal

to

the

tandard

density

of

0.

3gr/cu

in.)

d

rojectile

diameter

assumed

equal

to

0.

2235

n.

)

I

x

xial

moment

of

inertia

gr-in.

a

)

Iyransverse

moment

of

inertia

gr-in.

)

f o tatic

moment

coefficientperradian)

A

L.

C.MacAllister,tai,ACompendiumofBallistic

Properties

of

Projectiles

of

PossibleInterest

in

Small

Arms,

BallisticRe-

search

Laboratories

Report

No.

1532,ebruary1971.

4

"Designfor

Control

of

Projectile

Flight

Characteristics,"

Army

Materiel

Command

Pamphlet

AMCP706-242,

eptember

1966.

^A.J.emeister,"Important

MomentsofGeneralAxisymetric

Cartridge

nd

Projectile

Configurations,

"rankfordArsenal

Report

-2031,

December

971.

20


31/38


32/38

APPENDIX

B

Drag-reducing

Fumcr

Effects

This

Appendix

is

presented

to

examine

the

effecto fincorporating

adrag-reducing

umer

intohe

FABRliconcept

(design8 ).

Afvmer

s

amethodofreducing

the

base

drag

ofaprojectile

byinjectingthe

proper

amount

ofheat

and

mass

nto

the

projectile

base

region

duringflight.

Fumer

ammunition

may

be

thoughtof

as

being

somewhat

analogous

o

tracerammunitionbecause

heatand

massare

ejected

by

the

burninc

ofsome

material

in

thebaseregiontoreducethe

pressure

gradient.

However,hereneed

be

n o

illuminosity

requirement,

s

with

con-

ventional

tracer

bullets,

encethename

fumer.

Todate,

onsistentbasedrag

reductions

on

the

order

of

50

percent

,

ver

extended

ranges)have

been

attainedwith

certain

fumermaterials

a n d

projectile

baseconfigurations.

A

75

percent

reduction

in

basedrag

isestimated

as

a

reasonable

development

goal. Higherlevels

o f

re-

duction

areconsidered

unrealistic(except,ossibly

forbrief

portions

of

the

trajectory),

nd

are

therefore

not

presented.

Figures

B-l

andB-2

illustratevelocity

andstriking

energy

as

function

of

range

(from to

00

meters)

for

he

Ml93,

he

FABRL,

a n d

theFABRL,

itha

0

and

75percent

base

drag-reducing

fumer

effect.

The

500-meter

range

s

he

expectedrange

of

interest

for

rifle

engagements.

ThecurvesforheFABRLwithhe

fumereffect

were

not

adjusted

tocompensate

for

thenegligible

weight

loss

(approx-

imately grainswhenburnoutoccurs)

ue

to

the

burningofthefumer

material-

The37 .

1-grain

FABRLwith

a

75percent

reduction

of

base

ra j ,

(Figure

B-2)

achieves strikingenergycomparable

to

thatofthe

M193

ball

bulletatapproximately250meters. Beyond

this

range,

the

lighter

FABRL

with

75

percent

base

drag

reductionhasbetter

energy

retentionthan

theM193 .

FiguresB-3n dB-4illustratevelocity

n d

striking

energy

as

funct ion,

ofrange

(from

to

1 00meters)for

the

M193 ,

55

grain

AR 2

shape

bullet(solid

steel),

he

FABRL,

a n d

heFABRLwith 0

a n d

22

L


33/38

~

5

percentbase

drag

reduction,

The

1100-meterrange

if

he

usual

range

ofInterest

for

machine

un

engagements.

Figure

B-3

llustrates

hat

the

FABRL

with

0

percent

effective

umer

has

a

ballistic

co-

efficient

virtually

equal

to

that

of

themuch

heavierand

identically

haped

5

grain

AR2

projectile.

Figure

B-4hows

hat

the

with75percenteffectiveumerhas

more

trikingenergy

beyond

70

meters

hanthe5grainAR2

projectile.

Based

uponexperimental

data,allistic

ResearchLaboratories

determined

the

trikingenergy

the

55-grain

copper

plated

teel

AR2

shape

projectile

requires

o

penetrate

a

helmet

with

liner.

igure

B-4

illustrateshat

theFABRL

with

75

percent,

r

even

50

percent,

base,dragreductionwill

penetrate

helmet

with

linerbeyond1100

meters.

Fiom

informationon

the

FABRL

containedin

this

reportan d

certain

other

assumptions,aystemsanalysis

tudy

could

beper-

formedto

assess

he

effectivenessof

the

FABRLwith

fumer

n

both

the

rifle

nd

machinegun

roleu.

However,

amajortradeoff

with

the

use

of

theFABRL

as

common

rifle-machine

un

cartridge

wouldbethentroduction

of

ahigh

engineering

risk

totheSAW

project.

*

'Depending

upon

the

extent

of

interest

n

a

common

cartridge,

he

AR2,

.8 0

pound-second

mpulse

ystem

52-grain

bullet

launched

at

2509

ps),

resented

n

Reference

mightalso

be

considered.

2

M.J.iddington,

T.

H.

Oertel,

E.L.

Herr,

andV/.J.

Bruchey,

"Experimental

Ballistic

Properties

of

Selected

Projectiles

of

Possible

Interest

nSmallArms"U),BallisticResearchLab-

oratories

MemorandumReport

No.

2194,

June

972.

(CONFIDENTIAL)

23


34/38

K

1-

O

O

X

2

3

a it

V

*

J

*

o

o

_I

m

f-

K

CD

765459 limited analysis of a new ammunition concept

Documents