Expedient Homemade firearms

Prototype Design Drawings

T

T

H

H

E

E

‘

‘

Z

Z

I

I

P

P

’

’

G

G

U

U

N

N

(Measurements in millimetres unless otherwise stated)

T

T

h

h

e

e

Z

Z

i

i

p

p

,

,

o

o

r

r

P

P

e

e

n

n

G

G

u

u

n

n

,

,

a

a

s

s

i

i

t

t

i

i

s

s

s

s

o

o

m

m

e

e

t

t

i

i

m

m

e

e

s

s

r

r

e

e

f

f

e

e

r

r

r

r

e

e

d

d

t

t

o

o

,

,

i

i

s

s

p

p

e

e

r

r

h

h

a

a

p

p

s

s

t

t

h

h

e

e

s

s

i

i

m

m

p

p

l

l

e

e

s

s

t

t

o

o

f

f

a

a

l

l

l

l

i

i

m

m

p

p

r

r

o

o

v

v

i

i

s

s

e

e

d

d

f

f

i

i

r

r

e

e

a

a

r

r

m

m

s

s

a

a

n

n

d

d

i

i

s

s

u

u

s

s

u

u

a

a

l

l

l

l

y

y

f

f

o

o

u

u

n

n

d

d

i

i

n

n

.

.

2

2

2

2

c

c

a

a

l

l

i

i

b

b

r

r

e

e

d

d

u

u

e

e

t

t

o

o

t

t

h

h

e

e

r

r

e

e

l

l

a

a

t

t

i

i

v

v

e

e

l

l

y

y

l

l

o

o

w

w

p

p

r

r

e

e

s

s

s

s

u

u

r

r

e

e

s

s

g

g

e

e

n

n

e

e

r

r

a

a

t

t

e

e

d

d

b

b

y

y

t

t

h

h

i

i

s

s

s

s

m

m

a

a

l

l

l

l

c

c

a

a

r

r

t

t

r

r

i

i

d

d

g

g

e

e

.

.

I

I

d

d

e

e

c

c

i

i

d

d

e

e

d

d

t

t

h

h

a

a

t

t

a

a

n

n

e

e

e

e

d

d

e

e

x

x

i

i

s

s

t

t

e

e

d

d

f

f

o

o

r

r

a

a

s

s

i

i

m

m

p

p

l

l

e

e

h

h

o

o

m

m

e

e

m

m

a

a

d

d

e

e

v

v

e

e

r

r

s

s

i

i

o

o

n

n

o

o

f

f

t

t

h

h

i

i

s

s

t

t

r

r

i

i

e

e

d

d

a

a

n

n

d

d

t

t

e

e

s

s

t

t

e

e

d

d

‘

‘

’

’

c

c

o

o

n

n

t

t

r

r

a

a

p

p

t

t

i

i

o

o

n

n

’

’

’

’

a

a

n

n

d

d

c

c

a

a

m

m

e

e

u

u

p

p

w

w

i

i

t

t

h

h

t

t

h

h

e

e

f

f

o

o

l

l

l

l

o

o

w

w

i

i

n

n

g

g

d

d

e

e

s

s

i

i

g

g

n

n

!

!

I

I

d

d

e

e

s

s

i

i

g

g

n

n

e

e

d

d

t

t

h

h

i

i

s

s

w

w

e

e

a

a

p

p

o

o

n

n

w

w

i

i

t

t

h

h

t

t

h

h

e

e

c

c

a

a

v

v

e

e

a

a

t

t

t

t

h

h

a

a

t

t

i

i

t

t

s

s

h

h

o

o

u

u

l

l

d

d

b

b

e

e

b

b

u

u

i

i

l

l

d

d

a

a

b

b

l

l

e

e

i

i

n

n

o

o

n

n

e

e

d

d

a

a

y

y

o

o

r

r

l

l

e

e

s

s

s

s

,

,

a

a

n

n

d

d

I

I

t

t

h

h

i

i

n

n

k

k

I

I

h

h

a

a

v

v

e

e

a

a

c

c

h

h

i

i

e

e

v

v

e

e

d

d

t

t

h

h

a

a

t

t

r

r

e

e

q

q

u

u

i

i

r

r

e

e

m

m

e

e

n

n

t

t

.

.

T

T

h

h

e

e

R

R

e

e

c

c

e

e

i

i

v

v

e

e

r

r

.

.

The receiver is basically a steel tube into which the other component parts are

fitted. It consists of a 9 ¼ “ (233mm) length of 15.88mm (5/8”) x 1.5mm steel tubing,

as illustrated below. Into this tube a slot is cut, either by drilling a series of

interconnecting holes first, and then trimming the slot to shape with a file, or (for

the lucky individual) cut using a milling machine, if available! The slot should be ¼”

in width and will accept the breech block handle in due course. The slot is 98mm in

length, starting 67mm from any end of the tube.

C

C

o

o

m

m

p

p

o

o

n

n

e

e

n

n

t

t

P

P

a

a

r

r

t

t

s

s

(

(

T

T

h

h

e

e

r

r

e

e

a

a

r

r

e

e

o

o

n

n

l

l

y

y

t

t

h

h

r

r

e

e

e

e

c

c

o

o

m

m

p

p

o

o

n

n

e

e

n

n

t

t

p

p

a

a

r

r

t

t

s

s

t

t

o

o

t

t

h

h

e

e

w

w

e

e

a

a

p

p

o

o

n

n

)

)

1. Barrel

2. Breech Block

3. Breech Plug

4. Mainspring

67

98

Small Cut out in rear of slot to allow the weapon to be cocked.

Expedient Homemade firearms

Prototype Design Drawings

B

B

a

a

r

r

r

r

e

e

l

l

C

C

o

o

n

n

s

s

t

t

r

r

u

u

c

c

t

t

i

i

o

o

n

n

.

.

The Barrel can be nothing more than a short length of steel Airgun

barrel, turned to a diameter of 12.70mm (½”). The length of the barrel is

75mm. One end of the barrel is chambered using a 5.8mm diameter drill

bit to accept the .22 rimfire cartridge.

B

B

r

r

e

e

e

e

c

c

h

h

B

B

l

l

o

o

c

c

k

k

The breech block is just a 58mm long section of ½” diameter mild steel

bar. Into one end of the block a firing pin is fitted, made from a short

length of 2mm diameter drill shank. The pin must be carefully fitted so

as to be in the correct position to detonate the .22 rimfire cartridge.

75mm

58mm

Near to one end of the breech block a ¼” Dia’ hole is drilled

to accept the breech block cocking handle. The handle

consists of a simple steel pin about 1” in length.

FIRING PIN

BARREL

Breech Block

Expedient Homemade firearms

Prototype Design Drawings

M

M

a

a

i

i

n

n

s

s

p

p

r

r

i

i

n

n

g

g

The mainspring powers the breech block and should be reasonably

strong. I designed this gun to use a spring about 8- 9mm in diameter

and made from 20 gauge wire.

T

T

h

h

e

e

B

B

r

r

e

e

a

a

c

c

h

h

P

P

l

l

u

u

g

g

The breech plug is responsible for holding the spring and breech block

in place. It consists of nothing more than a 1” x ½” spring pin.

The pin is held in place by a 6mm diameter steel bolt and nut which

passes through the receiver from side to side, as illustrated below.

F

F

u

u

l

l

l

l

y

y

A

A

s

s

s

s

e

e

m

m

b

b

l

l

e

e

d

d

Pull back cocking handle and turn to right to cock weapon.

Load cartridge. When ready to fire disengage handle using thumb or

finger……

Bang!

Pull Back Handle

Bolt

This design may be very simple, but I think it would be easy and quick

to build !

Breech Plug

(Spring pin retained with

nut and bolt)

Breech Block

Barrel

Expedient Homemade firearms

Prototype Design Drawings

A

A

f

f

e

e

w

w

e

e

x

x

a

a

m

m

p

p

l

l

e

e

s

s

o

o

f

f

Z

Z

i

i

p

p

/

/

P

P

e

e

n

n

g

g

u

u

n

n

s

s

b

b

u

u

i

i

l

l

t

t

b

b

y

y

o

o

t

t

h

h

e

e

r

r

p

p

r

r

i

i

v

v

a

a

t

t

e

e

i

i

n

n

d

d

i

i

v

v

i

i

d

d

u

u

a

a

l

l

s

s

a

a

n

n

d

d

a

a

r

r

m

m

s

s

m

m

a

a

n

n

u

u

f

f

a

a

c

c

t

t

u

u

r

r

e

e

r

r

s

s

.

.

Armitage Pen Gun.

www.lawdogs.8m.com/ catalog.html

‘’Stinger’’ Pen Gun.

www.gurpsmaster.de/ undercover.htm

‘‘Mini Mag Light’’ .22 Torch Guns.

www.lawdogs.8m.com/ catalog.html

Expedient Homemade firearms

Prototype Design Drawings

American factory made ‘’Pen’’ pistol.

www.gurpsmaster.de/ undercover.htm

Unknown origin. Very nice homemade Pen Gun.

http://membres.lycos.fr/abpw/22-misc/pages/Pen_Gun1_by_Nobody.htm

Expedient Homemade firearms

Prototype Design Drawings

A .44 calibre Pen Gun. This is an old collectors piece made by the ‘Lake Erie

Chemical Co’.

www.adrax.com/ watsons/pengun.htm