CIP, London & Birmingham Proof Houses’ Barrel Proof Symbols Equivalency Table
For Use with Steel Shot Ammunition

CIP/UK STANDARD SUPERIOR STEEL
(HIGH PERFORMANCE)
London 2020
Birmingham 2020
London 2006
Birmingham 2006
London 1989 850 BAR 1200 BAR-
Birmingham 1989 850 BAR 1200 BAR-
London 1954 3 TONS PER □" 4 TONS PER □"-
Birmingham 1954 3 TONS PER □" 4 TONS PER □"-

*Please note the British Proof Authority will not give guidance on pre-1954 marks and recommends re-proof of such arms.

Use of Steel Shot Ammunition

There is much confusion over what steel ammunition can and can’t be used with shotguns bearing both CIP proof marks and historic national proof marks, or “proof symbols” as we prefer to refer to them. We will attempt to explain in the simplest terms possible what ammunition may be used with the relevant proof symbol.

It must be understood there are two types of steel ammunition, Standard Steel & High Performance Steel. 

Standard Steel ammunition can be used with any shotgun (other than Damascus/twist barrelled guns), in good order, bearing any of the above CIP, London or Birmingham symbols, provided the ammunition is of the correct length for the chamber and the barrel choking is less than half choke (some small cosmetic choke damage may still be incurred, even under these conditions). Ammunition packaging should denote that the ammunition is Standard Steel. However, if at all unsure whether your ammunition is Standard Steel, please consult the manufacturer. If you’re unsure whether your shotgun is suitable for use with Standard Steel ammunition please contact a competent gun dealer, gunsmith or the British Proof Authority for advice, this may involve the submission of your shotgun for inspection.

High Performance Steel ammunition can only be used with shotguns bearing a CIP fleur de Lys mark, as represented in the above table. The ammunition should be of the correct length for the chamber. The CIP recommends less or equal to half choke in relation to a given shot diameter for the Bore, please see the table below for clarification.

BoreMaximum Recommended Choke RestrictionShot Diameters 
10 & 12 BoreHalf choke or less (≤ 0.5mm) 
For shot larger than 4mm (> 4mm)
16 BoreHalf choke or less (≤ 0.5mm) For shot larger than 3.5mm (> 3.5mm)
20 BoreHalf choke or less (≤ 0.5mm) For shot larger than 3.25mm (> 3.25mm)
28 BoreHalf choke or less (≤ 0.5mm) For shot larger than 3mm (> 3mm)
.410 BoreHalf choke or less (≤ 0.5mm) For shot larger than 2.5mm (> 2.5mm)

Ammunition packaging should denote that the ammunition is High Performance Steel. However, if unsure whether your ammunition is High performance Steel, please consult the manufacturer. If unsure whether your shotgun is suitable for use with High Performance Steel ammunition please contact a competent gun dealer, gunsmith or the British Proof Authority for advice, this may involve the submission of your shotgun for inspection.


A.A.Brown & Sons is asking owners of older guns not proofed for the use of High Peformance Steel not to panic. We are suggesting that in the short term, customers continue to use lead as they have been and in the longer term, make a change to bismuth or standard steel depending on their type and amount of shooting. There are options for those that need to shoot with High Peformance Steel and if you would like to discuss them or anything relating to the use of non-toxic ammunition, please do contact us.

Address

A.A.Brown & Sons
1 Snake Lane
Alvechurch
Birmingham
B48 7NT
(Visit by appointment only)


Contacts

Email: enquiries@aabrownandsons.com
Phone: +44 (0) 121 445 5395 

Links

Proof Symbols Table
Matthew Brown Photography
ABAS Productions
Losgi.com

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