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L1A1/C1A1 spec sheet

BriarJumper

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From the old MSN Group's L1A1Armourer's webpage,


Barrel Group
Application Notes

Standards

Reference

Torque



Unbreeching
(Safety Verification Test)

Min: 120 ft. lb.
Max: 140 ft. lb.

Min: 60 ft. lbs.

(Barrel must show no signs of movement


Bore

Australian and British
L1A1 rifles

0.297 in.
(Diameter plug gauge must pass freely)

Canadian C1
(below S/N 0L6000)

Canadian C1
(Above S/N 0L6000)

0.300 in.
(Diameter plug gauge must pass freely)

0.2980 in.

(Diameter plug gauge must pass freely)

Chamber Edge

Max: 0.041 in.
(Depth below barrel rear face)

Rear Face
Edge Radius

Min: 0.008 in.
Max: 0.014 in.

Radial Alignment / Timing

(Using factory breeching fixture)

Max: +/- 0.010 in.

Gas Piston Length

(FN mfg marked only)

Min: 11.595 in.
Min: 11.565 in.


Head Diameter

Min: 0.4295 in.
Max: 0.4305 in.


Pitting

Head of Piston

Max: 0.020 in. (depth)


Gas Block
Internal Width

Max: 0.775 in.
(lug entry to lug entry)

Gas Port

Standard

First Stage Repair

Second Stage Repair

Min: 0.095 in.
Max: 0.098 in.

0.102 in. - 0.106 in.

0.109 in. - 0.133 in.


Foresight

Height above foresight block

Max: 0.465 in.

Gas Plug

Cylindrical Diameter

Min: 0.4507 in.
Max: 0.4525 in.

Gas Slot Width

Min: 0.180 in. (Top)
Max: 0.160 in.
(Bottom)

Gas Slot length

Min: 0.240 in.
Max: 0.260 in.

Gas Regulator

End Float

Max: 0.007 in.
(regulator set on '0')

Breeching Washer

Sizes


Washer No.

Thickness (inch)

1
2
3
4
5
6
7
8

Flash Eliminator
Washer

Sizes: -

Sizes 1 - 12 available to
all countries

'A' sizes only in service with
British and Canadian Armies


Washer No.

Thickness (inch)

1

0.1500

1A

0.1517

2

0.1535

2A

0.1552

3

0.1570

3A

0.1587

4

0.1605

4A

0.1622

5

0.1640

5A

0.1657

6

0.1675

6A

0.1692

7

0.1710

7A

0.1727

8

0.1745

8A

0.1762

9

0.1750

9A

0.1797

10

0.1785

10A

0.1832

11

0.1820

11A

0.1867

12

0.1855







Lower Receiver
Group

Application Notes

Standards

Reference

Hinge Pin

Unit and Field

0 .905 in. (Length)
0.311 in.
(Diameter)

Base

0.910 in. (Length)
0.313 in. (Diameter)

Locking Catch

Lug Engagement

Min: 0.060 in.
(front to rear, full contact)
OR
(line contact within 0.035 in. of the front)


Lug and Catch overlap

0.090 in.

Vertical Lever /
Receiver clearance

Min: 0.003 in.(Unit)


Min: 0.010 in.(Field)


Min: 0.030 in.(Base)(Australian)


Min: 0.100 in. (Base)( British)


Return Spring Tube

Torque

Min: 20 ft. lb.
Max: 30 ft. lb.


Backsight
Assembly

Aperture size

Min: 0.099 in.







Upper Receiver
Group

Application Notes

Standards

Reference

Firing Pin
Protrusion

Canadian

Min: 0 .040 in.
Max: 0.050 in.

Australian

Min: 0.045 in.
Max: 0.058 in.

British

Min: 0.050 in.
Max: 0.058 in.

Firing Pin Hole
Diameter

Accept: 0.079 in.
Reject: 0.084 in.

Locking Shoulder

Protrusion above upper
receiver immediately aft
of shoulder

Max: 0.012 in.


Receiver Locking Shoulder Bore

0.2978 in. (Standard)
0.2982 in.
(Oversize /1 or Y)
0.2990 in. (Oversize /2)
0.2998 in. (Oversize /3)


British Locking Shoulder Sizes

<CHART>

Ejector

Height Above Carrier Guide Rail

Min: 0.019 in.

Hinge Pin Bore
Diameter

British

Min: 0.315 in.
Max: 0.317 in.

Australian

Min: 0.318 in.
Max: 0.320 in.

Cartridge
Headspace

(Unit and Field)

Min: 1.6325 in.
Max: 1.643 in.


(Base)

Min: 1.6325 in.
Max: 1.638 in.

Australian S/N to AD6100001

Max: 1.638 in. (Unit, Field, Base)

Locking Latch Lug

Lug Wear

Max: .0030 in. (measured at corners)











Fire Control
Parts Group

Application Notes

Standards

Reference

Trigger

Height of Bent

Min: 0 .058 in.

Axis Pin Hole Diameter

Max: 0.197 in. (Including Ovality)

Axis Pin Sleeve Diameter

Min: 0.194 in.

Axis Pin Diameters

Min: 0.154 in. (Shank)
Min: 0.246 in. (Shoulder)

Trigger Width Across Side Faces
(Where Subject to Wear)

Min: 0.449 in.

Hammer

Axis Pin Hole

Max: 0.204 in. (Including Ovality)

Axis Pin Diameters

Min: 0.201 in. (Shank)
Min: 0.293 in. (Shoulder)

Selector

Distance Between Back of
Lever and Stud on Shank

Max: 0.125 in.

Distance Between Receiver
and Underside of the Lever
with Selector Halfway
Between S and R

Max: 0.030 in.










Springs Group

Application Notes

Standards

Reference
Extractor Spring
C1 S/N up to 0L6000

Number of Coils: 25.5
Max. Free Length: 1-5/8 in.
Min. Free Length: 1-3/8 in.

C1 S/N 0L6000 and up

Number of Coils: 24
Max. Free Length: 1-9/16 in.
Min. Free Length: 1-3/8 in.

Firing Pin Spring

Number of Coils: 17.5
Max. Free Length 1-9/32 in.
Min. Free Length 1-1/16 in.

Load Test

7.5 lbf Initial Movement (Installed)

Piston Spring

Number of Coils: 72
Max. Free Length: 11-1/8 in.
Min. Free Length: 9-1/4 in.

Return Spring
(Outer)

Number of Coils: 12
Max. Free Length: 21-13/16 in.
Min. Free Length: 19 in.


Load Test

8.6 lbf +/- 0.5 lbf
@7.700 in. +/-0.800 in.

Return Spring (Inner)

Number of Coils: 142 *info
Max. Free Length: 19-3/4 in.
Min. Free Length: 17 in.


Load Test

5.75 lbf +/- 0.35 lbf
@ 7.000 in. +/- 0.750 in.

Hammer Spring
Assembly

Free length of assembly 3.22 in.
Min. first movement of
Compression 14.51 lbf min.

Load Test

24.51 lbf @ a min compressed length of 2.62 in.










Performance
Standards

Application Notes

Standards

Reference

Trigger Assembly
Performance

Pull Off

7 - 9 lbs. (Standard)
6 lbs.
(Canadian Match min.)

Bolt Hold-Open
Assembly
Performance

Release Force
(with captured bolt/carrier)

Min: 13.5 lbf. (Unit and Field)
Min: 14.5 lbf
(Base)

Return / Recoil
Assembly

Initial Rearward Movement
of Captured Carrier from Bolt
Hold open.

Min: 13.5 lbf (Unit and Field)
Min: 14.5 lbf (Base)


System Cycling
and Ejection

9 ft. min @ a Min. regulator
setting of 5 (Base)


9 ft. min. @ a Min. regulator
setting of 4 (Unit and Field)

Feed Performance

Release bolt hold open with
rifle at 80 degrees and full 20
round magazine, repeat 3 times
 

gunplumber

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As one who collects data, there are some points that raise an eyebrow. Particularly the second level gas port increase. .133" Are you fucking kidding me? the rifle should be dead-lined long before. And that is not in any UK or Aussie or Canadian ANY level armorer's manual, because I have memorized them all. And melded them all into my own publication. Second level .110 is the max in any armorer publication. Personal experience I'll go to .120 on some extreme circumstances, such as Turkish G1s. And .125 on shit DSA shorties.

But overall, the data seems pretty good. Inasmuch as it matches what my 30 years of research and personal experience says is appropriate.
 

OLDMANPBK

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As one who collects data, there are some points that raise an eyebrow. Particularly the second level gas port increase. .133" Are you fucking kidding me? the rifle should be dead-lined long before. And that is not in any UK or Aussie or Canadian ANY level armorer's manual, because I have memorized them all. And melded them all into my own publication. Second level .110 is the max in any armorer publication. Personal experience I'll go to .120 on some extreme circumstances, such as Turkish G1s. And .125 on shit DSA shorties.

But overall, the data seems pretty good. Inasmuch as it matches what my 30 years of research and personal experience says is appropriate.
I noticed that you have the gas regulator end float spec in your book.
 

gunplumber

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I noticed that you have the gas regulator end float spec in your book.

I do not. Which makes it curious that you noticed it.

I do not because it does not appear in any published manual.

Although I do recognize it as an issue.

Side note - Indian Gas regulators are not the same ID as British Gas regulators, although the Indian will duplicate the Fazakerley Proof. They are hard to tell apart as both exhibit sloppy production.

Although not as important as the gas cylinder GO/NOGO which is adversely affected by sustained blank firing. Which I do note, and why I do not recommend using suppressors with the FAL/L1A1 platform

If blanks will make the gas cylinder out of round, what does one think the backpressure of a silencer will do?
 

OLDMANPBK

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I do not. Which makes it curious that you noticed it.

I do not because it does not appear in any published manual.

Although I do recognize it as an issue.

Side note - Indian Gas regulators are not the same ID as British Gas regulators, although the Indian will duplicate the Fazakerley Proof. They are hard to tell apart as both exhibit sloppy production.

Although not as important as the gas cylinder GO/NOGO which is adversely affected by sustained blank firing. Which I do note, and why I do not recommend using suppressors with the FAL/L1A1 platform

If blanks will make the gas cylinder out of round, what does one think the backpressure of a silencer will do?
Oh yes you do. 🙂 11.6.4 under 2. Gas Regulator, 8 dots down.
 
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