Dear shooter. The following is an extract from the NRA website:

A recent incident has brought to light the fact that solid copper or bronze bullets (i.e. with no lead core) have been trialled and shot on at least two ranges. A significant number of these bullets have been found not to have behaved in the same way as bullets made with a conventional lead and gilding metal combination, causing spent bullets to exit the stop butt in unpredictable directions despite none having actually exited a danger area as far as we know. There is therefore the distinct possibility that their ricochet characteristics may differ markedly from conventional bullets. The retained velocity and the maximum range achievable is also significantly increased.

Range Danger Areas are defined on the basis of conventional bullets with a lead core (using both ballistic and ricochet data) and the Range Danger Areas of Bisley ranges (both Century and Stickledown) lie very close to public roads and housing at their extremities. Since we do not yet have enough information on which to base a risk-assessed judgement, it will be necessary to prohibit the use of 'solid' bullets on any of the Bisley Ranges with immediate effect until an informed judgement can be made.

Advice is being sought from the Technical Advisory Section (TAS) at Warminster and from other technically qualified sources, and a decision [which may be based on parameters other than maximum muzzle velocity (MV) and muzzle energy (ME)] will be made as quickly as possible. While it is regretted that this unavoidably late notification may cause problems for some shooters or competitors in the Imperial Meeting your understanding and compliance in maintaining safe range procedures is requested and required.
Until this matter is resolved at NRA level, we have to impose the same ban at Jubilee with immediate effect.

Please inform anyone who is not on this distribution list, and who may come to shoot at Jubilee (eg in the Tullibardine, for which entry forms are already out) of this ban.

Keith Baxby, Chairman WARC