shooting through glass

7/29/2019 Shooting Through Glass

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SUMMARY OF UK GOVERNMENT

REPORTJAMES A DOWLE

SHOOTING THROUGHGLASS


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Contributors to the work

British military sources (Various)

Police Scientific Development Branch

Weapons, Explosives ResearchCentre (NI)

FBI Ballistic Research Facility

GSG9 Numerous LE and Military sources

worldwide


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AIMTo introduce experienced snipers

to the factors to be consideredbefore attempting a shot throughan intermediate (glass) barrier


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FORMAT OF PRESENTATION

Types of Glass Things to watch out for!

What happens to bullets as they pass

through glass? Spalling

Shooting from behind glass

Synchronised shooting Checklist

How experiments were conducted

Questions?


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TYPES OF GLASS

Float/Annealed Glass

Toughened/Tempered Glass

Laminate Glass Wired Safety Glass

Lexan/Plastics

Applied Plastic Films


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Float/Annealedglass

DomesticGla

zing

Older buildings

Commercial

Schools

Public buildings


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Toughened/

TemperedGlass

Vehicle side

windows Insulated Glazing

Units (IGUs)

ModernCommercialbuildings

Mirrored or tintedfinishes


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Tempered glass

is about ten

times as strongas annealed

glass


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Laminated Glass

Large shop fronts

SafetyApplications

Vehiclewindshields

SecurityApplications


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Others

Wired Safety Glass

Lexan/Plastics

Applied Plastic Films


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Things to watch out for..


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Manifestation


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Glass Fins on Walls and

Ceilings


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Questions?


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What Happens to Bullets asthey pass through Glass?

Cores and jackets separate

Deflected from true path Bullet Mass is lost

Energy/Wounding potential is lost

Greater the angle of the glass the

greater the above effects


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Separation of jackets andcores

(a) (b) (c) (d) (e) (f)

Shot

No.Glass

AngleDepth of

Penetration(mm)

Recovered Bullet

Mass (grams)Percentage of

retained Weight 9.7gComments

59 90 460 6.4 66% 1 main cavity, 2 smaller and 7 smallholes

60 90 Bullet exited through side of soap and lost. Numerous small holes.

61 90 245 1.2 jacket4.7 core

12%49%

1 main cavity, 1 smaller and

numerous small holes.

62 45 220 jacket200 core

3.1 jacket3.8 core

32%39%

3 Channels and 2 smaller holes.


1.8 jacket2.1 core

19%22%

2 Channels and 2 smaller holes.


3.0 jacket2.0 (split core)

31%21%

2 Channels.


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Deflection

The bullets will tend to deflectthe shortest distance through

angled glass


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DisintegrationFall of Shot in relation to Expected Scoring Area

Lapua 170 grain FMJ 2x4mm Double Glazing

-50

0

50

-50 0 50

(mm)

(mm)

Lapua 170 gn FMJ 90 deg

Lapua 170 gn FMJ 45 deg

The circle represents the

expected scoring area

without glass for this

ammunition type


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Disintegration


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180gn PPSP at 75 metres Target distance 2 metres


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180gn PPSP at 75 metres. Target distance 2 metres.

Glass at 45 and 90 degrees.

4mm Float glass single pane.

010

20

30

40

50

60

70

80

90

100

0 100 200 300 400 500 600

Depth of Penetration (mm)

P

ecentageofRe

tainedBullet

Weight

90 deg 45 deg cores 45 deg jackets


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Disintegration


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Comparison of TBTL and SHPBT in 4mm Float Glass

at various angles and glass to target distances at

100yds.

0

10

20

30

40

50

60

70

80

90

100

0 100 200 300 400 500 600

Depth of Penetration (mm)

Pecentag

eofRetainedB

ulletWeight

TBTL

SHPBT


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Spalling

Always leaves glass surface at 90 degreesirrespective of angle bullet leaves


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Shooting from behind glass


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Comparison on Head Sized Target 25m

and 50m

-

0

250

250 -150 -50 50 150 250

Swiss P Styx

Lapua Mega

Federal Soft point


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Synchronised Shooting

Coordinated shot at same POA

Close together

As near 90 degree line of fire aspossible

Must be practised


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Checklist

Ammunition Type

Range to Glass

Distance of target

behind glass Angle of shot to

glass

Type of Glass

Ammunitionsuitable

Backstop

Degree of Accuracy Lighting/Identification

Test Fired?

Secondary missilehazard

Firing from behindglass?

Method of breaking? Secondary danger

area


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How the experiments were

conducted


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Questions?

shooting through glass

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