Re: Lead-free shot
As far as I know the British Army only uses shotguns in jungle warfare, usually for the guys on point. That would mean using something like SSG a few quite large (9mm) lead balls to penetrate brush at close quarters.
British hunters can buy Eley bismuth shot but bismuth being about 15% less dense than lead means shorter range and effectiveness, however bismuth shot is always used for hunting wetland birds. The only other real alternative to lead for density would be tungsten, not only very expensive but would destroy a shotgun barrel quickly, although it is used in military anti-materiel rounds like the British AS 50 .
I think the Dutch have banned lead shot completely.