Indeed - antique guns, muzzle loaders and small bores have seemingly all been overlooked. Whether it’s assumed we can just use bismuth or similar I don’t know, or whether (cynically) our ‘needs’ are forgotten in the hope these categories will be reluctantly ‘sacrificed for the good cause’ I don’t know. .410 factory lead loads are expensive enough as is. As those who shoot them know, steel is a no-go for all these guns, so really that leaves home-loading carts with bismuth for small bores, expensive factory bismuth or home loads for older pre-1954 proofed guns and bismuth for the front-stuffers. For those not in the know, the UK Proof houses say don’t use standard steel loads in guns nitro proofed before 1954.
Steel shot needs very thick shot cups/wads or else the barrel is scoured and written off, so it fundamentally can’t be used in muzzle loading guns. The physics of things prevent the necessary thick-wall wad being used in a small bore - there’d be little room for shot. Anyway, previous experiments on the fantastic fourten shotgun resources website (now archived) shows that steel doesn’t pattern well in small gauge anyway.
There doesn’t seem to be any comment re lead shot on the MLAGB website.
Bah humbug!